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 GUIDE TO THE STUDY OF 
 
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Ciadonia ciM^toletla 
 
A GUIDE TO THE STUDY 
 
 OF 
 
 LICHENS 
 
 ALBERT SCHNEIDER, M. D., Ph.D. 
 
 Professor of Botany, Materia Medica and Pharmacognosy, 
 California College of Pharmacy, San Francisco 
 
 With frontispiece in color 
 
 and 
 
 Twenty plates 
 
 SECOND EDITION 
 
 BOSTON 
 
 KNIGHT AND MILLET 
 
 1904 
 
Copyright, 1898 
 By Albert Schneider 
 
 All rights reserved 
 
CONTENTS. 
 
 Preface 
 Introduction 
 
 PART I. 
 The General Consideration of Lichens. 
 
 SECTION I. 
 
 The History of Lichenology 1 
 
 I. From the Earliest Time to Wallroth and 
 
 Meyer (1825) 2 
 
 II. From Wallroth and Meyer (1825) to the Close 
 
 of 1896 8 
 
 SECTION II. 
 
 The Uses of Lichens 16 
 
 I. The Function of Lichens in Nature ... 17 
 
 II. The Economic Value of Lichens .... 18 
 
 SECTION III. 
 
 What are Lichens? 25 
 
 I. The Origin of a Lichen 29 
 
 II. The Relation of the Lichens to Algjs and 
 
 Fungi 33 
 
 in. Lichens as Morphological Units .... 36 
 
 57G1.' 
 
 •^ 
 
VI CONTENTS. 
 
 SECTION IV. 
 
 The Morphology and Physiology of Lichens ... 39 
 
 I. The Thallus 39 
 
 1. The Cbdstose Type 41 
 
 2. The Foliose Type . -. 42 
 
 3. The Fbuticose Type 44 
 
 II. The Apothecia 45 
 
 1. The Fungal Type 46 
 
 2. The Thalline Type 47 
 
 III. Accessory Structures 48 
 
 1. The Soredia 48 
 
 2. The Cyphell-e 49 
 
 3. The Cephalodia 50 
 
 4. The Spermagonia 50 
 
 SECTION V. 
 
 The Occurrence and Distribution of Lichens ... 52 
 
 I. The Latitudinal and Altitudinal Distribution 
 
 OF Lichens 52 
 
 SECTION VI. 
 
 Lichens and the Naturalist 56 
 
 I. The Collection of Lichens 56 
 
 II. The Study of Lichens 63 
 
 III. The Pbesebyation of Lichens 65 
 
 PART II. 
 The Systematic Study of Lichens. 
 
 SECTION I. 
 Systems of Classification 73 
 
 SECTION II. 
 
 Keys to the Study of Lichens 76 
 
 I. Artificial Kky to the More Important Genera 
 
 OCCUBBINQ IN THE UNITED STATES ... 77 
 
 II. Natural Key to the Families 80 
 
CONTENTS. VH 
 
 Description of Families, Genera and Species ... 81 
 
 I. Caliciace^ SI 
 
 II, Cladoniace^ 87 
 
 III. Lecideace^ 102 
 
 IV. Gbaphidace^ . . ; 124 
 
 V. Physciace^ 132 
 
 VI. Parmeliace^ 144 
 
 VII. Verrucariageje 169 
 
 VIII. COLLEMACE^ . . 179 
 
 IX. Pannariace^ 184 
 
 Lichens Imperfecti, or False Lichens 201 
 
 The Continental Range of the Lichens Occurring in 
 
 THE United States 202 
 
 Alphabetical List of the Genera and Species Repre- 
 sented in the United States 204 
 
 General Index 225 
 
 Plates 235 
 
PREFACE. 
 
 This little work is especially written and arranged for the 
 use of amateurs in the study of lichens. By this it is not in- 
 tended to convey the idea that the presentation of the subject- 
 matter is unscientific, incorrect or even out of date. The 
 treatment of the subject is in harmony with the most recent 
 results obtained by tlie leaders in the study of lichenology ; I 
 have simply endeavored to present these results in such a way 
 that they may be comprehended by all ; in other words, an at- 
 tempt has been made to popularize our present knowledge of 
 lichens. It should, however, be kept clearly in mind that 
 only the known facts or the completed work of science can be 
 popularized. The advance-work of science, that is, the work 
 whose aim it is to make 7}ew discoveries or to correct errors, can 
 never he popularized ; as soon as this is attempted it ceases to 
 be advance-work. This statement is intended for those of the 
 laity who are inclined to speak of scientific work as " non- 
 sense " or as " a morbid taste for using big words." It is also 
 intended for the serious consideration of those would-be scien- 
 tists who are too anxious to "popularize science." It is 
 further hoped that this statement will avoid possible erro- 
 neous conclusions as to the intended purpose of this book. 
 
 The existing nomenclature-difiiculty does not concern or 
 interest the average student of nature. In fact, the leading 
 scientific specialists are themselves as yet wholly at sea as to 
 when and where the controversy will end. For this reason 
 the citation of authorities is omitted. Tlie names given are 
 well authenticated, so that those who have the desire and the 
 
X PREFACE. 
 
 opportunity may enter into the consideration of the synonymy 
 and tlie nomenclature-controversy. 
 
 The lichens described are. the more common forms occur- 
 ring in the United States, those with which tlie collector is 
 likely to come in contact. At the close is given a fairly 
 complete list of the lichens found in the United States ; this 
 will prove helpful to those who wish to make exchanges. 
 The artificial key is especially intended for the use of those 
 who are not in possession of a compound microscope. 
 
 I take this opportunity to express my grateful obligations 
 to Dr. N. L. Britton and Prof. Lucian M. Underwood, of 
 Columbia University, who placed at my disposal the Univer- 
 sity collection of lichens. I am also greatly indebted to my 
 wife, who has kindly given aid in correcting the manuscript 
 and in reading the proof. 
 
 Albert Schneider. 
 
 Chicago, January, 1898. 
 
PREFACE TO SECOND EDITION. 
 
 The changes to the second edition are the addition of six 
 full-page half-tone illustrations of typical representatives of 
 the three gi'eat subdivisions of the lichens ; namely, the 
 crustose, foliose, and fruticose. These veill be of great 
 value to beginners in the study of this remai'kable group of 
 plants. 
 
 Since the issue of the first edition no important discov- 
 eries have been made in lichenology, hence no changes have 
 become necessary in the text. 
 
 I take this opportunity to express my obligations to Miss 
 Alice Eastwood, of the California Academy of Science, and 
 K. S. Gray, Attorney, San Francisco, for the loan of mate- 
 rial, as well as for assistance in collecting specimens. 
 
 Albert Schneider. 
 
 San rRANCisco, August, 1903. 
 
INTRODUCTION. 
 
 Lichens form a group of plants which has been 
 not so much overlooked and neglected as misunder- 
 stood and abused. The term lichen is rather un- 
 familiar, but not so the term " moss," by which the 
 plants here referred to are quite generally known 
 to layman as well as to poet. And, indeed, the term 
 moss is justifiable if we trace it to its Scandinavian 
 origin. All comparatively small thalloid cryptogams 
 — that is, flattened, stemless and flowerless plants — 
 were known as moss (most, mossa, moos, mus). The 
 term, therefore, included lichens, liverworts and mosses 
 proper. But from the present standpoint of science 
 lichens are not mosses, as will be made clear later ; 
 lichens are an independent group of plants having no 
 genetic relationship to mosses. 
 
 Nor must it be supposed for a moment that lichens 
 are uninteresting and insignificant. With the one ex- 
 ception of marine algae, no plants present such truly 
 beautiful and artistic features to the amateur in nature- 
 study. No group of plants is so easily obtainable or 
 
Xll INTRODUCTION. 
 
 lends itself so readily to the critical examination of the 
 student and to the decorative fancies of the artisan. 
 Neither is it necessary to enter a plea for the kindly 
 consideration of these plants because they have been 
 neglected and abused. Lichens do not require pity : 
 they are more than competent to hold their own in 
 the great struggle for existence. Indeed, many of the 
 much petted and much praised higher plants owe their 
 very existence to the lichens. It is true, lichens can- 
 not boast of an exalted origin or noble ancestry, but 
 they have gradually advanced in a beneficent life-work, 
 so that at present their lowly origin is wholly lost 
 sight of. 
 
 Let us, therefore, obtain a better insight into these 
 plants, so that we may judge them more fairly and as- 
 sign them to their proper position in the world of life, 
 and duly credit them with the grand work they are 
 performing. Let us hope that no one, on seeing a 
 lichen, will say, " Oh ! that is a moss," or, " It's noth- 
 ing ; it just grows on trees." A lichen is as deserving 
 of recognition as the oak upon which it grows or the 
 reindeer whose life it sustains. 
 
PART I 
 
 GENERAL CONSIDERATION OF LICHENS 
 
THE HISTORY OF LICHENOLOGY. 
 
 SECTION I. 
 
 THE HISTORY OF LICHENOLOGY. 
 
 The history of lichenology is a remarkable one. It 
 indicates that this special science has progressed in a 
 devious and interrupted course. It is only within a 
 few years that scientists have arrived at any compara- 
 tive certainty as to the true nature of these plants. 
 Wonderfully absurd opinions were entertained as to 
 their origin and economic uses. For these reasons a 
 brief historical review is not only interesting but 
 highly important. 
 
 Historically, time is usually divided into periods or 
 epochs ; such divisions are, however, more or less 
 arbitrary and depend somewhat upon the judgment of 
 the author. The establishment of periods very greatly 
 simplifies the presentation of an historical review. It 
 must, however, not be supposed that the greater the 
 number of epochs or periods the simpler the history; 
 generally the contrary is true. 
 
 The most exhaustive history of lichenology is that 
 by Krempelhuber, published in the year 1867. This 
 author divides the history of our science ii^to six 
 periods, as follows : 1, from the earliest times (Theo- 
 phrastus) to Tournefort (1694) ; 2, from Tournefort 
 to Micheli (1729) ; 3, from Micheli to Weber (1779) ; 
 4, from Weber to Acharius (1810) ; 5, from Acha- 
 
 Library 
 N. C, State Collect 
 
2 GUIDE TO THE STUDY OP LICHENS. 
 
 rius to De Notaris (1845) ; 6, from De Notaris to 
 1867. In my *' Text-book of General Lichenology" 
 I have retained Krempelhuber's limitations of the 
 first three periods ; the others have been changed, 
 and the review has been completed to the beginning 
 of 1897. As thus modified, the fourth period is from 
 Weber to Wallroth and Meyer (1825), the fifth from 
 Wallroth and Meyer to Schwendener (1868), the 
 sixth from Schwendener to Reinke (1894), and the 
 seventh beginning with Reinke. The reasons for 
 the changes will become evident upon the considera- 
 tion of the historical review as here given. 
 
 For the purposes of a very brief review it was 
 thought best to recognize two grand periods. Only a 
 few of the more important workers in lichen ology will 
 be mentioned. At the present time the publications on 
 lichens number many thousands ; to collect and digest 
 these is the work of years. The beginner will, how- 
 ever, feel somewhat relieved to learn that of the 
 thousands of publications on lichens only a compara- 
 tively few are of any intrinsic value or add to our 
 knowledge of the subject. 
 
 I. FROM THE EARLIEST TIME TO WALLROTH AND 
 MEYER (1825). 
 
 This may be characterized as the period in which 
 no real scientific study was made of lichens. The 
 botanical systematists of the time devoted their at- 
 tention to the higher plants, especially those of real 
 or imaginary economic value. The lower plants 
 were quite generally neglected, lichens in particular. 
 
THE HISTORY OF LICHENOLOGT. 6 
 
 In a work ascribed to Solomon a large number of 
 higher plants are mentioned but not a single crypto- 
 gam. The reason why lichens should be especially 
 neglected becomes apparent when we consider that 
 with few exceptions they are not striking in size, 
 color or form, nor do they seem to possess any marked 
 useful or harmful properties. 
 
 No historian has been able to give any reliable in- 
 formation regarding the earliest knowledge and uses 
 of lichens. Evernia furfuracea is said to have been 
 found with Egyptian mummies, where it was doubtless 
 used as packing material. There is no reason why 
 this lichen as well as others (species of JJsnea in par- 
 ticular) should not have been used for similar pur- 
 poses by the ancient peoples of northern Africa, Arabia, 
 Italy and other countries in which these plants occur 
 very plentifully. Theophrastus (371-286 B. C), a 
 pupil of Aristotle, was perhaps the first writer who 
 left any record of lichens. From his rather imperfect 
 descriptions we are led to believe that he was more 
 or less familiar with JJsnea barhata and Rocella tincU 
 oria. The former no doubt attracted attention be- 
 cause of its beard-like growth upon trees, oaks in par- 
 ticular. The latter has been long known on account 
 of its coloring properties. These two lichens were 
 also mentioned in the works of Dioscorides and 
 Pliniiis. With these exceptions, lichens received no 
 attention until the sixteenth century, when science, 
 art and literature awoke from the paralytic state into 
 which it had sunk since the first century. About the 
 middle of the sixteenth century, Ruellius, Gessner, 
 
4 GUIDE TO THE STUDY OF LICHENS. 
 
 CaBsalpiuus and Camerarius, who were among the 
 earliest commentators on the writings of Theophrastus, 
 Dioscorides and Plinius, did little more than to reiter- 
 ate what was already known of lichens. At the close 
 of this century about twenty-eight species or forms of 
 lichens were described. The Scotch botanist Morison 
 (1683) described fifty-six lichens, some of which were 
 quite well figured. 
 
 The Italian botanists were the beginners in the 
 study of the structure and growth of lichens. Mal- 
 phigi (1686) was the first to call attention to the 
 soredia, which he considered to be the true seeds of 
 lichens, since he had observed that new plants were 
 developed from them. Porta (1591) gave some very 
 crude explanations of the origin and growth of lichens, 
 which indicated that he had some fairly correct ideas 
 of the nature of these plants, while Morison, who 
 seemed to have been an accurate observer otherwise, 
 expressed it as his opinion that lichens were excremen- 
 titious matter produced by the soil, rocks and trees. 
 
 At the close of the seventeenth century about 125 
 lichens were known and described. Especially im- 
 portant was the work of Tournefort (1694-1719). 
 This author called special attention to the apothecia 
 and some of the spores. His descriptions of the his- 
 tological characters were of necessity crude, owing to 
 the imperfections of the simple microscopes, the com- 
 pound microscope being as yet unknown. 
 
 The systematic study of lichens really began with 
 the Florentine botanist Micheli (1729). Heretofore 
 all lichens had been placed in the one group " lichen," 
 
THE HISTORY OF LICHENOLOGY. 5 
 
 though some considered them as " mosses " or " fun- 
 goid " mosses. Micheli proceeded to arrange all the 
 known species or forms into thirty-eight orders based 
 upon the general macroscopical characters and the con- 
 sistency of the thallus. He illustrated the orders and 
 also studied the apothecia and the spores. Twelve years 
 later John Dillen issued his noteworthy " Historia Mus- 
 corum," in which the lichens are classified as mosses. 
 His work is well illustrated, and in many respects the 
 system of classification is superior to that of Micheli. 
 
 After the above botanists others exercised their 
 ingenuity in establishing systems of lichens. Some 
 authors classified them with mosses, while others 
 placed them with fungi. The various groups were 
 quite universally based upon the external appearance 
 and nature of the thallus. Linne, " the immortal 
 Swede" (1753), combined all lichens in one group in 
 agreement with Tournefort. He, however, established 
 sub-groups based upon the characters of the thallus 
 as well as upon those of the apothecia. 
 
 It will be remembered that at first there was a ten- 
 dency to classify lichens as a distinct group of plants ; 
 later to consider them as mosses or even as funafi. 
 
 o 
 
 This doubt and uncertainty continued to grow until 
 the close of the seventeenth century, when the confu- 
 sion reached its highest point. They were not only 
 classed as mosses and fungi, but also as algae, sponges, 
 liverworts, etc. This difference of opinions was due 
 to the fact that the knowledge of the lower plants, of 
 lichens in particular, was very imperfect. Linne, who 
 never pretended to be a friend of the cryptogams, des- 
 
6 GUIDE TO THE STUDY OP LICHENS. 
 
 ignated lichens as ^^ rustici pauperrimi,'' which might 
 well be translated as " the poor trash " of vegetation. 
 This lack of interest in the lower organisms was quite 
 universal and explains why lichens were neglected, 
 particularly the really insignificant crustose forms. 
 As the result of the combined efforts of the various 
 lichenographers some 500 species or forms of lichens 
 were known at the close of the eighteenth century. 
 
 The first investigator who made an attempt to study 
 the morphology and physiology of lichens was J. 
 Hedwig (1784). Though his conclusions were in the 
 main wrong, yet his investigations served as a stimulus 
 and an inducement to further study. This author, 
 was the first to make a special study of the sperma- 
 gonia. He also studied the spores and soredia. 
 He believed that the spermagonia were the first to 
 develop and that the apothecia and soredia developed 
 upon these subsequently. Furthermore, the sper- 
 magonia were looked upon as the male reproductive 
 organs, the soredia as the fertilizing elements and 
 the apothecia with the spores as the female organs. 
 A. P. De Candolle (1798) made some interest- 
 ing experiments as to the manner in which the 
 different lichens take up their food-supply. During 
 the same year Acharius, who is often spoken of 
 as the " father of lichenology," issued his " Prod. 
 Lich. Suec," in which he expressed great uncertainty 
 in regard to the manner of fertilization and the nature 
 of the reproductive organs. He even questioned 
 whether lichens were plants and expressed a desire to 
 classify them as polyps. Georgi (1779) made the 
 
THE HISTORY OF LICHENOLOGY. 7 
 
 first chemical studies of lichens. He found that they 
 contain such organic substances as oil, resin and 
 mucus and various inorganic salts. In the year 1810 
 Acharius issued his " Lichenographia Universalis," 
 which was the most voluminous and complete work 
 on lichens yet issued. It is simply a manual of lichens 
 with rather imperfect descriptions of species. His 
 illustrations, particularly those of the spores, are poor. 
 One would expect better work from so eminent a bot- 
 anist. He did not make use of the spore-characters 
 in his system. Other eminent botanists, as Lamarck, 
 De Candolle, Fries, F^e and Eschweiler, established 
 systems of classification ; all of which were artificial 
 and inadequate. 
 
 Some of the leading botanists of the time believed 
 that lichens were related to fungi as well as to the 
 algae. Accordingly Agardh, Voigt, Endlicher, Lind- 
 ley, Reichenbach and others considered lichens as a 
 distinct class to be placed between the algae and fungi. 
 Sprengel and Oken also considered them as a distinct 
 class but placed them between liverworts and algae ; 
 De Candolle placed them between liverworts and 
 fungi. Many other botanists still considered lichens 
 as a subordinate group belonging to various natural 
 classes, as algaj, fungi, mosses, etc. 
 
 At the beginning of the nineteenth century the 
 belief in spontaneous generation was quite general. 
 Sprengel and others were convinced that, under favor- 
 able circumstances, lichens were evolved from decaying 
 substances, or the decomposition of water. Agardh 
 (1820), the eminent algologist, stated that he had 
 
8 GUIDE TO THE STUDY OF LICHENS. 
 
 observed the development of the lichen Collema limO' 
 sum from the alga Nostoc muscorum var. lichenoides. 
 A general belief of that time was that the so-called 
 " primal substance," or " green substance of Priestley " 
 (perhaps Protococcus vulgaris or other unicellular 
 alga) could develop into algae, lichens, mosses and 
 other lower plants. Nees von Esenback was wont to 
 guide his pupils to the old castle at Pottenstein in 
 order to demonstrate ad oculos how the green sub- 
 stance of Priestley occurring on the stone walls could 
 develop into a lichen, while if placed in water it would 
 develop into an alga. 
 
 Thus we see that during this entire period, which 
 extended over two thousand years, scarcely anything 
 more was done than to name and roughly describe 
 between 500 and 600 species of lichens. The heated 
 discussion, the wrangling and the uncertainty in regard 
 to the origin and position of lichens was simply evi- 
 dence of ignorance and not a sign of profound knowl- 
 edge of the subject. Scarcely a ray of scientific light 
 had as yet penetrated the Stygean darkness in which 
 these highly interesting plants were enwrapped. It 
 simply shows that scientific progress, like all progress, 
 is slow and its devious path is strewn with thorns and 
 s tu mblin g-blocks . 
 
 II. FROM WALLROTH AND MEYER (1825) TO THE 
 CLOSE OF 1896. 
 
 This might be designated as the period of scientific 
 lichenology. Leading botanists now began to study 
 the life-history, the morphology, histology and physi- 
 
THE HISTORY OF LICHENOLOGY. 9 
 
 ology of lichens. It must, of course, be cmpliasized 
 that this was heretofore practically impossible owing 
 to the imperfections of the microscope. The com- 
 pound microscope was introduced at the beginning of 
 the nineteenth century, but, like all innovations, was 
 comparatively imperfect and was looked upon with 
 disfavor by many scientists who should have known 
 better ; some even going so far as to openly assert 
 that the compound microscoj)e would never excel the 
 most perfect simple lenses. 
 
 The impetus to the scientific study of lichens was 
 given by two German scientists, Wallroth and Meyer, 
 who, peculiarly enough, began their work independently 
 but covered much the same ground and published their 
 results in the same year (1825). Both made a special 
 study of the morphology, growth and metamorphosis 
 of the lichen-thallus. Wallroth's style is very in- 
 volved. Each sentence contains a long series of 
 parenthetical clauses often occupying nearly an octavo 
 page. His terminology is also peculiar and requires a 
 special study. On one question the two eminent 
 writers were diametrically opposed ; while Meyer 
 believed in the spontaneous generation of lichens, 
 Wallroth did not, it being his opinion that they de- 
 veloped from gonidia and spores as well as by vegeta- 
 tive propagation. Wallroth gave a very detailed de- 
 scription of the structure and function of the gonidia, 
 soredia and apothecia as well as of the tliallus. Al- 
 though this author did most excellent work there is no 
 evidence to show that he made use of the compound 
 microscope ; in some instances he did not even use the 
 
10 GUIDE TO THE STUDY OF LICHENS. 
 
 simple lens. Meyer's studies were perhaps even more 
 comprehensive than those of Wallroth. He entered 
 into a careful investigation of the structure and meta- 
 morphosis of the thallus and apothecia, the gonidia 
 and spores, the growth and nutrition of lichens and 
 their relation to the substratum. 
 
 Stitzenberger (1862) was perhaps the first to em- 
 phasize the importance of the spore-characters in the 
 classification of lichens. According to this author it 
 is principally the generic distinctions which are to be 
 based upon the spore-characters. Lichens with 
 colored and colorless spores are not to be included in 
 the same genus, nor those whose spores differ in the 
 number or direction of the septa, etc. According to 
 the systematist Kbrber (1865) 1,051 species of lichens 
 had been collected in Germany and Switzerland. Of 
 this number Korber described 272 species as new. 
 Massalonga (1853) made a careful study of the struct- 
 ure of crustose lichens and concluded that the spore- 
 characters as well as the form and structure of the 
 apothecia and thallus should be considered in the es- 
 tablishment of genera. Fries (1861) recognized the 
 importance of the spore-characters but considered the 
 form of the spermatia as of nearly equal significance ; 
 in this he was seconded by other authors. The Eng- 
 lish lichenologist Mudd (1861) rightly objected to this 
 procedure because nothing was known of the function 
 of spermagonia and also because the spermatia were 
 not sufficiently varied in form to be of marked impor- 
 tance in classification. Nylander (1858) more than 
 any other investigator has emphasized the importance 
 
THE HISTORY OF LICHENOLOGY. 11 
 
 of the spermatial characters in classification. This 
 author, however, did excellent work in the morphol- 
 ogy of lichens. He was also the first to point out the 
 double affinity of lichens ; on the one hand they 
 showed a close resemblance to fungi, on the other to 
 algae. He published a list of all the known lichens, 
 which included 1,348 species, 298 of which were de- 
 scribed as new. Nasgeli (1847) classified lichens as 
 algae under the group Lichenaceae and placed them be- 
 tween the Confervaceae and Exococcaceae. Itzigsohn's 
 (1854) opinions underwent great change as regards 
 the spermagonia. At first he was inclined to look 
 upon them as parasitic fungi, abnormal spore-organs, 
 apothecia or even parasitic lichens. Subsequently he 
 stated that they were the antheridia analogous to 
 those of mosses, of which the spermatia were the 
 spermatozoa. Somewhat later he was inclined to be- 
 lieve that the gonidia were the female organs and the 
 spermatia the male organs. Species of the algae 
 Pleurococcus^ Ulothrix, and others, were supposed to 
 be free unfertilized gonidia. Tulasne (1852) gave us 
 a very complete and scientific memoir on the histol- 
 ogy of lichens. Lindsay (1856) wrote a most excel- 
 lent popular treatise on British lichens. A little 
 later Schwendener (1858-1868) began his morpho- 
 logical studies of lichens which were even more com- 
 plete than those of Tulasne. In 1868 Schwendener 
 came to the conclusion that the so-called gonidia of 
 lichens were nothing more nor less than simple-celled 
 algae and that the spore-bearing portion of the lichen 
 was a fungus living parasitically upon the algae. 
 
12 GUIDE TO THE STUDY OF LICHENS. 
 
 This in a nutshell is the great discovery of Schwen- 
 dener and which has revolutionized the study of 
 lichens. Reinke (1873) pointed out that the relation 
 of fungus and alga as it occurs in the lichen was not 
 ordinary parasitism ; that it indicated a relationship in 
 which both organisms were benefited. This relation- 
 ship he designated consortism. De Bary (1879) de- 
 scribed this phenomenon more fully and designated it 
 symbiosis, that is a "living together" for mutual 
 benefit. 
 
 As a result of Schwendener's investigations lichens 
 were considered as fungi and were classified as such. 
 There was, however, great opposition to this method 
 of classification, especially on the part of the pure 
 systematists. In 1874 Stahl made a special study of 
 the spermagonia which led him to conclude that the 
 spermatia were the male fertilizing elements. Sturgis 
 (1890), an American scientist, seconded the conclu- 
 sions of Stahl. To Tuckerman we owe most of our 
 systematic knowledge of the American lichens. His 
 descriptions of species, carefully given, makes his 
 work the first that could be utilized by those of ordi- 
 nary capabilities. The style of Leighton's manual of 
 British lichens is peculiar ; the descriptions of species 
 are given in a peculiar mixture of English and Latin 
 which made it necessary for him to append an exten- 
 sive glossary of terms. Crombie (1895), also a Brit- 
 ish lichenologist, retains the same style. Hue (1892) 
 has published a list of lichens from which it may be 
 concluded that about four thousand species are known 
 at the present time. 
 
THE HISTORY OF LICHENOLOGY. 13 
 
 Within comparatively recent years there have been 
 numerous investigators who have made a special study 
 of the relationship of fungus and alga as they occur in 
 a lichen. We cannot cite authors nor enter into any 
 discussion of the results obtained. 
 
 The general conclusions may be summarized as fol- 
 lows : 
 
 1. Certain algae, mostly of the simpler Chlorophy- 
 ceae and Cyanophyceae have entered into an intimate 
 biological relationship with certain fungi mostly de- 
 rived from the Ascomycetes (sac-fungi). 
 
 2. A lichen is represented by a fungal portion and 
 an algal portion. The two parts enter into a sym- 
 biotic relationship which is of such a nature that both 
 are very materially benefited. The two organisms 
 are complementary to each other, one supplies what 
 the other lacks. 
 
 3. The fungal portion cannot exist independently, 
 while the algal portion can. 
 
 4. The algal types are fairly well known. They 
 are (1) Cystococcus humicola which occurs in the 
 majority of lichens ; (2) Pleurococcus vulgaris ; (3) 
 Exococcus ; (4) Glceocapsa ; (5) Chroococcus ; (6) 
 Nostoc ; (7) Stigonema; (8) Chroolepus ; (9) Con- 
 fervacece. 
 
 Bornet, Baranetzky, Famintzin and Woronin are 
 among those whose efforts have aided in giving us a 
 more exact knowledge of lichens. Jumelle (1892) is 
 perhaps the first who has entered into a careful study 
 of the carbon-assimilating function of lichens. Reinke 
 (1894-1896) after considerable study came to the 
 
14 GUIDE TO THE STUDY OF LICHENS. 
 
 conclusion that lichens shotild be considered as a dis- 
 tinct class. According to this author a lichen is as 
 much a morphological unit as a fern or an oak. A 
 lichen is not a fungus parasitic upon algae. He has 
 shown that the existence of the lichen is dependent 
 upon the relationship of the fungal portion and the 
 algal portion. Separating the two destroys the lichen. 
 Lindau (1895) objects to Reinke's views and agrees 
 with Schwendener. Darbishire (1897) is a strong 
 supporter of Reinke. He has also made a careful 
 study of the soredia (soralia) as they occur in the 
 Pertusarias. As for myself I favor Reinke's view as 
 will be explained more fully later. 
 
 Thus concluding the historical review with the be- 
 ginning of the year 1897, we find the status of our 
 knowledge of lichens somewhat as follows : 
 
 1. Schwendener's theory of the dual nature of 
 lichens is quite universally accepted as correct. That 
 is, a lichen consists of a fungal and an algal por- 
 tion. 
 
 2. Reinke's theory of the autonomy of lichens is 
 beginning to receive general recognition. According 
 to this view a lichen is not a fungus parasitic upon 
 algae. The mutual interdependence of the fungus and 
 alga is so great that in many instances neither can 
 exist alone. 
 
 3. Lichens doubtless form a distinct class equal in 
 systematic importance to mosses, fungi, liverworts, 
 etc. 
 
 From this historical review we learn that lichenol- 
 ogy has had a very checkered career and that the ad- 
 
THE HISTORY OF LICHENOLOGY. 15 
 
 vance has been very slow. Most of the real scientific 
 progress has been made within the past thirty or forty 
 years. Considerable work is yet to be done before 
 our knowledge of lichens arrives at any considerable 
 degree of accuracy. 
 
16 GUIDE TO THE STUDY OP LICHENS. 
 
 SECTION II. 
 THE USES OF LICHENS. 
 
 Whatever exists, exists for a purpose. If it exists 
 for a purpose, it serves some use in the economy of 
 nature. In many instances this purpose or use is not 
 apparent because not understood. If a thing is decried 
 as useless it simply indicates that it is not sufficiently 
 understood. Nature produces no useless things. From 
 the standpoint of the optimist, all things, inclusive of 
 those designated as bad or harmful, work ultimate 
 good. 
 
 As indicated in the historical review, lichens have 
 been unfairly judged. They have been looked upon 
 as vegetable monstrosities. One comparatively recent 
 author considered them as mosses which had been 
 checked in their development. Linne looked upon 
 them as the " beggarly among plants." Others con- 
 sidered them as waste products of earth, rocks and 
 trees. They were quite generally considered as alto- 
 gether insignificant and useless, if not harmful. Even 
 poets were inclined to speak of them disparagingly. 
 The great part that lichens play in the economy of 
 nature was wholly overlooked. There were, however, 
 a few who ascribed to these plants medicinal properties 
 which they do not possess. As an article of diet and 
 
THE USES OP LICHENS. 17 
 
 in the dyeing industry, lichens found a useful place 
 early in the history of civilization. 
 
 I. THE P^UNCTION OF LICHENS IN NATURE. 
 
 The task that lichens perform in the economy of 
 nature is indeed Herculean and out of all proportion 
 to their size. They are the hardy pioneers preparing 
 the way for the advance of the less hardy vegetation. 
 Their hardiness is shown by their ability to resist 
 greater extremes of temperature than any other plants, 
 or even animals. They have gained the reputation of 
 being able to live on nothing but air and sunlight. 
 This is, perhaps, scarcely true, but it is a fact that they 
 require less organic food than other plants. In gen- 
 eral, lichens are to be compared to green chlorophyll- 
 bearing plants, since they take up carbon dioxide from 
 the air and give off oxygen. They thus add their mite 
 toward keeping the air in a suitable condition for the 
 respiration of higher animals. 
 
 The most important function that lichens perform 
 in nature is the preparation of soil. Many of the 
 crustose lichens occur upon the hardest rock, to which 
 they are closely attached, forming dirty grayish or 
 greenish patches. Erroneous opinions as to the man- 
 ner in which lichens disintegrate the rock are very 
 prevalent. A recent author puts it as follows : " One 
 peculiarity of some lichens is the power they have to 
 burrow into the hardest rocks, even flint and granite, 
 thus making for themselves homes (faveoli)." Other 
 authors make similar statements. Such statements 
 are wholly unscientific, hence untrue. No lichen, has 
 
18 GUIDE TO THE STUDY OF LICHENS. 
 
 the power to burrow into rock of any kind, not even 
 into vegetable tissue ; such a thing is physically im- 
 possible. Nevertheless lichens disintegrate the hardest 
 rock, and it is done approximately in the following 
 manner : Rock-lichens, as well as others, secrete vari- 
 ous acids which have a solvent action upon the less 
 resisting rock-particles. As a result the rock crumbles 
 and the hyphse of the lichen extend between the loos- 
 ened particles. The lichen may thus be almost entirely 
 imbedded in the disintegrated rock-material ; the whole 
 mass being held together and to the unaffected rock 
 the gelatinous hyphse. In time the lichen dies, decays 
 and becomes mingled with the rock-particles, forming 
 a suitable substratum for the higher lichens, such as 
 the large foliose and fruticose forms. In turn these 
 also decay and aid in forming a suitable soil for mosses, 
 ferns and even higher plants ; that is, death and decay 
 gives rise to new life. Throughout nature we find 
 that those living give up their lives that others may 
 live. Lichens are the most altruistic of all living or- 
 ganisms, since they live wholly for the good of others. 
 Nearly all other plants require at least a substratum 
 resulting from the death and decay of others. Many 
 lichens live upon wholly inorganic substrata and exert 
 their entire life-energy for the benefit of other living 
 creatures. 
 
 II. THE ECONOMIC VALUE OF LICHENS. 
 
 We shall here refer to some of the more important 
 uses to which lichens have been put. Other special 
 uses will be referred to in the discussion of the species. 
 
THE USES OF LICHENS. 19 
 
 All lichens contain a larger or smaller percentage 
 of a starch-like substance known as lichenin, or lichen- 
 starch. It has the same chemical composition as 
 starch (Cg H^o O5) but differs in that it usually does 
 not give the blue reaction with iodine. It is to this 
 substance that lichens owe their nutritive properties. 
 From time immemorial the poor of various countries 
 have made use of lichens as an article of diet, just 
 when it was first so used is impossible to determine ac- 
 curately. Excavations of prehistoric cave-dwellings 
 ''^ermany) have revealed the presence of lichens 
 (Cladonia rangiferind) among the bones of various 
 animals, which would indicate that man of that early 
 period had already made some economic use of lichens. 
 The " miraculously " supplied manna of the Israelites 
 (Exodus xvi, 14, 15) in the wilderness is supposed to 
 have been a species of Lecanora (Z. esculentd). This 
 lichen occurs very plentifully in the mountainous dis- 
 tricts of Tartary, Algeria and other parts of northern 
 Africa. The plant occurs in small nodular masses, 
 grows and spreads quite rapidly under favorable con- 
 ditions. These lichens are only loosely attached to 
 the substratum, so that they are readily torn loose and 
 carried by the wind into the valleys below, where the 
 ignorant and oftentimes hungry peasants suppose them 
 to be bread rained from heaven. Travellers in the above 
 countries have reported several noteworthy and exten- 
 sive "rains of manna." The Kirghiz Tartars eat this 
 lichen under the name of '-earth-bread." 
 
 Iceland moss {Cetraria islandicn) h;is been most 
 extensively used as an article of diet because it con- 
 
20 GUIDE TO THE STUDY OF LICHENS. 
 
 tains a high percentage of lichenin. The peasantry of 
 Iceland, Norway and Sweden powder it and mix it 
 with the flour of various cereals and mashed potatoes, 
 from which an " uncommonly palatable and healthful 
 bread is prepared." A diet of this lichen was also 
 said to prevent a peculiar form of scurvy, or elephan- 
 tiasis, known as " Iceland scurvy," quite prevalent in 
 Iceland and the Scandinavian peninsula. 
 
 Rock-tripe, a species of Umbilicaria, has often been 
 the means of saving the lives of arctic explorers, not- 
 ably the members of the Franklin expedition, also of 
 trappers and hunters in Canada and Alaska. Some 
 of the companions of Franklin found, to their sorrow, 
 that a diet of this lichen produced a severe intestinal 
 inflammation, no doubt due to the bitter principle it 
 contains. This bitter principle is more or less present 
 in all lichens, and is said to be removed by repeated 
 washings or soaking in a solution of potash or some 
 other alkali. In the northern countries of Europe a 
 common method of preparing lichens for the table was 
 to make a decoction in milk after they had been re- 
 peatedly washed in water. It is, however, very difl[i- 
 cult to remove the objectionable bitter principle entirely, 
 and for this reason lichens were never extensively used 
 as an article of diet, excepting in cases of famine. The 
 peasants of Norway and Sweden collect large quantities 
 of various lichens as fodder for their cattle. Every 
 one is familiar with reindeer-moss (^Gladonia rangi- 
 ferind) as a food-supply for the reindeer of Lapland. 
 
 Perhaps the most important and oldest use to which 
 lichens had been put was in the dyeing industry. 
 
THE USES OF LICHENS. 21 
 
 Theophrastus and Dioscorides described Rocella tincU 
 oria as a " marine fungus growing upon rock, possess- 
 ing coloring properties," from which it is concluded 
 that dye made from the lichen was known before that 
 time. It was in use before the time of Pliny. The 
 "blue and purple" of the Old Testament (Ezekiel, 
 xxvii, 7) no doubt refers to the coloring substance 
 obtained from this lichen. 
 
 After the fall of the Roman empire the knowledge 
 of the use of the dye obtained from Rocella seems to 
 have been lost. About the year 1300, Federigo, a 
 Florentine of German parentage, accidentally redis- 
 covered the method of preparing and using this dye. 
 He is said to have achieved such great success in his 
 commercial transactions therewith that in time he be- 
 came the head of a distinguished family, the Oricellarii, 
 who were later known as the Rucellarii and Rucellai. 
 From these names are derived orseille, the name 
 given to the coloring substance, and Rocella, the group 
 of lichens from which orseille was prepared. For 
 more than a century Italy supplied the market with 
 orseille derived mainly from lichens collected on the 
 islands of the Mediterranean. After the discovery of 
 the Canary Islands, in 1402, much of the dye was ob- 
 tained from those islands; still later from the Cape 
 Verde Islands, as well as from other islands and coun- 
 tries. Later it was found that species of Lecanora, 
 Pertusan'a, Umbilicaria, Gyrophora, etc., yielded ex- 
 cellent dyes. 
 
 The method of preparing the dye is quite compli- 
 cated and many complex chemical reactions are in- 
 
22 GUIDE TO THE STUDY OF LICHENS. 
 
 volved. In general, it may be stated that the lichen is 
 pulverized and macerated for some time in some alka- 
 line solution, as lye, or ammonia, whereby a beautiful 
 purple color is obtained. Orchill, cudbear and lit- 
 mus are different names for the same coloring sub- 
 stance. The first is the English preparation which 
 occurs as a rich purple paste ; the second is the Scotch 
 preparation which is found in the market as a carmine 
 or crimson powder ; the third is the Dutch prepara- 
 tion and occurs in small oblong cakes of an indigo- 
 blue color. Litmus, as well as the other dyes, 
 has the peculiarity of turning red in the presence of 
 an acid and blue in the presence of an alkali. The 
 litmus-paper so extensively used in chemical labora- 
 tories is ordinary filter paper dipped into a neutral 
 solution of litmus. 
 
 Later orseille was used principally in dyeing silken 
 goods. France more than any other country improved 
 upon the methods of extracting the dye, as well as in 
 applying it. As to the value of the dye it may be 
 stated that about the middle of this century the 
 " orchella-weed " sold at prices ranging from $100 to 
 more than $1,000 per ton. The chief objection to the 
 use of orseille is its instability, being subject to fading ; 
 furthermore, the process of dyeing is very apt to injure 
 the cloth. Orseille is also used by artists as a pigment. 
 
 In Sweden Evernia vulpina is known as " Ulf- 
 mossa" (Wolf's moss), because it was said to have 
 been used in poisoning wolves. According to Virey, 
 the lichen is powdered and mixed with powdered 
 glass, which is sprinkled upon meat exposed for wolves 
 
THE USES OF LICHENS. 23 
 
 to feed upon. The wolves eat of tliis and die. Accord- 
 ing to Fabricius, nux vomica^ and not powdered glass, 
 "was mixed with (he lichen, which seems more probable. 
 Tlie dog-lichen {Peltigera canina) formed the basis 
 of the noted " anti-hydrophobia powder " (pulvis anti- 
 lyssns or pulvis contra rabiem) of the London Phar- 
 macopoea (1721 to 1788). In the history of the 
 Royal Society (London) it is recorded that several 
 mad dogs belonging to the Duke of York were cured 
 by this powder. Dr. Mead recommends the following 
 treatment in a case of hydrophobia : " The patient is 
 bled and ordered to take a dose of the powder (equal 
 parts of the lichen and red pepper powdered) in warm 
 milk for four consecutive mornings ; thereafter he 
 must take a cold bath every morning for a month and 
 for two weeks subsequently three times a week." 
 Dioscorides recommended Usnea harhata, known as 
 the " beard moss," in certain diseases peculiar to 
 women. Later it was very highly prized as a remedy 
 for whooping-cough, epilepsy and as an anodyne. It also 
 formed the main ingredient in powders recommended 
 to promote the growth of hair. The yellow Physcia 
 parietina was considered a specific in jaundice and 
 ■was also used as a substitute for quinine. During the 
 Napoleonic wars (1809-1815) fevers of all kinds 
 raged in the military hospitals. Quinine, which was 
 then the popular remedy for fever, became very scarce, 
 on account of its rapid consumption and because of the 
 commercial blockade which prevented its importation. 
 Tlie Austrian government therefore offered a prize 
 of five hundred ducats for the discovery of a cheap 
 
24 GUIDE TO THE STUDY OF LICHENS. 
 
 and readily accessible substitute for quinine. Sanders, 
 who secured the prize in part, proposed Physcia 
 parietina as such a substitute. It proved, however, 
 very unsatisfactory and its use was soon entirely dis- 
 continued by physicians. 
 
 From their alleged aptitude for imbibing and 
 retaining odors and scents the powder of several fruti- 
 cose lichens formed the basis of certain perfumes 
 which were celebrated in the seventeenth century. 
 The astringency of some species rendered them ser- 
 viceable in tanning and even in brewing ; the beer of 
 a certain Siberian monastery, celebrated for its peculiar 
 bitterness, owed this to Sticta pulmonaria. French 
 and Scandinavian chemists employed Cetraria island- 
 tea and Cladonia rangiferina in the manufacture of 
 alcohol. The method of procedure is essentially as 
 follows: The lichens are treated with sulphuric or 
 hydrochloric acid, which transforms the lichenin into 
 glucose ; this, being allowed to ferment, produces 
 alcohol. Two pounds of the lichen furnishes about 
 one pint of alcohol. 
 
 Attempts were also made to use lichens in the 
 manufacture of paper but the results were very unsat- 
 isfactory, as these plants contain no tenacious fibres. 
 They are still very extensively used in the decorative 
 work of the taxidermist. Some species furnish a gum 
 used in the manufacture of pasteboard. 
 
 In conclusion, it may be stated that the medicinal 
 virtues of lichens are largely imaginary. The only offi- 
 cinal lichen to-day is Cetraria islandica, a decoction of 
 which is recommended as a tonic for convalescents. 
 
 
WHAT ARE LICHENS ? 25 
 
 SECTION III. 
 WHAT ARE LICHENS? 
 
 In order to comprehend the true nature of lichens 
 it is necessary to have a correct idea of their origin ; 
 we must have some conception of their j^osition in 
 nature, of their relation to other plants. Lichens ori- 
 ginated in a manner wholly different from any other 
 group of plants. Their history of development is most 
 remarkable, and stands without a parallel in the world 
 of living things. In order to make clear this wonder- 
 ful origin and development it is necessary to enter into 
 a brief consideration of fungi and the lower algae. The 
 impatient reader may ask, "What do fungi and algas 
 have to do with lichens ? " He will soon learn that 
 without these plants lichens could not have come into 
 existence. We shall begin the discussion with algae. 
 
 Every one is more or less familiar with the lower 
 alga2 ; they occur plentifully upon tree-trunks, fences, 
 upon flower-pots, walls and woodwork of greenhouses, 
 etc.; they form the green scum on ponds and brooks, in 
 watering-troughs, in fact, in nearly all moist })laces 
 and in water exposed to sunlight and warmth. These 
 plants are very small, the individual plant is, in fact, 
 too small to be seen by the naked eye. Several hun- 
 dred must become associated to form a minute green 
 speck. 
 
26 GUIDE TO THE STUDY OF LICHENS. 
 
 If we scrape off a small fragment of the green coat- 
 ing of a tree or flower-pot and examine it under a 
 microscope we find that it consists of numerous minute 
 globules, perhaps five-thousandths of an inch in diam- 
 eter. Each globule is an individual alga and is nothing 
 more or less than a single cell. Not all of the lower 
 algae are single-celled however ; many consist of chains 
 or filaments of cells or even of a highly complex struct- 
 ure. The algae with which we are concerned are either 
 single-celled or form simple or branching chains of 
 cells. Their structure will be more fully described 
 later. 
 
 Algae contain a green substance known as chloro- 
 phyll. It is this substance which enables the organism 
 to assimilate inorganic food ; a function peculiar to all 
 chlorophyll-bearing plants and which distinguishes them 
 from animals and parasitic plants. Animals and fungi 
 can only assimilate the food-substances directly or in- 
 directly prepared by the chlorophyll-bearing plants. 
 This brief reference to the algae will suffice for the 
 present. The facts to be distinctly kept in mind are 
 that alg£e contain chlorophyll and have the power of 
 assimilating inorganic food-substances under the influ- 
 ence of sunlight. Now as to the fungi. 
 
 Every one has seen toadstool-s, puff-balls, mould 
 on bread and other organic substances kept in moist 
 and rather dark places, rust on wheat and other cereals, 
 smut on corn, etc.; all of these are fungi. Every one 
 has heard of bacteria and is more or less familiar with 
 the role they play in disease ; some have no doubt 
 heard of the importance of bacteria in the manufacture 
 
"WHAT ARE LICHENS ? 27 
 
 of cheese, in tanning, and in tlie making of butter; all 
 are familiar with processes of fermentation. These 
 bacteria, wlietlier indifferent, harmful or beneficial, 
 and the producers of fermentation, belong to the 
 fungi. 
 
 It is also generally known that fungi are either 
 saprophytic or parasitic, that is, they require organic 
 food obtained from dead or living organisms. In this 
 they differ markedly from chlorophyll-bearing plants, 
 as already indicated. Scientists have however deter- 
 mined that fungi were originally chlorophyll-bearing 
 and hence able to assimilate inorganic food ; in other 
 words, fungi are algae which have lost their chlorophyll 
 and the functions pertaining thereto. How did they 
 come to lose their chlorophyll ? The history of this 
 change is, perhaps, something as follows : Many ages 
 ago certain of the algse accidentally came in contact 
 with higher plants, from which they absorbed some of 
 the more soluble food-substances. The association re- 
 duced the amount of work to be done by the chloro- 
 phyll of the parasite ; as the association continued the 
 morphological and physiological changes in the alga 
 tended toward a more and more marked parasitism. 
 Every one is familiar with the fact that inactivity of 
 an organ causes it to become dwarfed and more or less 
 functionless. Chlorophyll became extinct in these 
 parasitic algae simply because it was functionless : all 
 of the organic food was prepared and supplied by the 
 host. This change was by no means sudden ; it re- 
 quired many ages to produce the change from bright 
 green alga to colorless fungus, or, in other words, to 
 
28 GUIDE TO THE STUDY OF LICHENS. 
 
 convert the independent chlorophyll-bearing organism 
 into a dependent chlorophylless organism. 
 
 The above is in brief the history of the origin and 
 development of all vegetable parasites. Even now we 
 can find all gradations between parasitic states just 
 making a beginning, as, for example, some species of 
 Nostoc and Protococcus, and the most highly developed 
 parasitism, as, for example, most of the fungi. Sapro- 
 phytes differ from parasites only in that the originally 
 green, hence chlorophyll-bearmg plants, became adapted 
 to live upon dead organic matter rather than living 
 organisms. It must also be kept in mind, that as par- 
 asitism and saprophytism progressed the resulting 
 fungi underwent structural changes ; so that it is in 
 many instances practically impossible to recognize the 
 resemblance to any living forms of algae. Scientists 
 are, however, quite generally agreed that fungi are 
 derived from algae. 
 
 As a rule, fungi reproduce their kind by means of 
 very minute microscopic bodies known as spores. All 
 of the higher fungi may be divided into two groups 
 according to the manner in which the spores are formed ; 
 in the one group they are formed on the ends of spe- 
 cialized hyphae, known as hasidia, in the other group 
 they are formed within specialized hyphee, known as 
 spore-sacs (Asci). The latter are therefore commonly 
 known as sao-fungi. We have to deal with the sac- 
 fungi (Ascomyctes) only. There is, however, one 
 Southern lichen ( Cord) which forms basidio-spores. It 
 is the only exception occurring in the United States 
 and is, furthermore, of rare occurrence. Keeping, there- 
 
WHAT ARE LICHENS? 29 
 
 fore, in mind, that in the discussion of lichens we are 
 concerned with certain genera of the lower algae be- 
 longing to the Chlorophyceae and the Cyonophyceae, and 
 a division of the higher fungi known as sac-fungi 
 (Ascomycetes), we shall now briefly ex^Jain the phylo- 
 genetic history of a lichen. The origin of one lichen is 
 in all essential respects similar to that of any other, so 
 that one example will suffice to make clear the origin 
 of all lichens. 
 
 I. THE ORIGIN OF A LICHEN. 
 
 As to the time when the first lichen was formed 
 nothing definite is known. We may, however, safely 
 conclude that they existed in the geological periods 
 along with algae and fungi. We are certain that they 
 could not have existed before the development of fungi, 
 as explained above ; we also know from what has gone 
 before that algae antedate fungi, from which we con- 
 clude that lichens began their existence many ages 
 later than the first alga? and fungi. From the great 
 structural and functional specializations that lichens 
 have undergone, we must again conclude that they be- 
 gan their existence far back in the geologic ages, that 
 is, millions of years ago. 
 
 If we select one of the foliose Parmelias as a type, 
 the hypothetical assumption is that its origin was as 
 follows : A sac-fungus (Ascomycete) evidently belong- 
 ing to the genus Patella, found it diflicult to maintain 
 a thrifty existence as a saprophyte ; the organic food- 
 supply was no longer adequate to keep up sufiicient 
 energy to maintain a successful struggle for existence. 
 
30 GUIDE TO THE STUDY OF LICHENS. 
 
 The many generations of a life of dependent luxury 
 had greatly crippled its energies; functionally it be- 
 came more and more weakened, until finally it could 
 not even digest a sufficient quantity of the food already 
 prepared, or, in other words, it no longer possessed suf- 
 ficient vitality to feed itself. In order to regain its 
 lost vitality it must again appropriate a larger amount 
 and better quality of food ; inorganic food was not 
 available, because it had lost its chlorophyll. *If the 
 fungus could, however, prevail upon some chlorophyll- 
 bearing organism to prepare inorganic food-substances 
 for its assimilation the problem would be solved ; that 
 is, it must press into its service some plant having 
 chlorophyll. As already indicated, ordinary parasitism 
 with higher plants did not suffice: these plants were 
 not sufficiently adapted to its needs. The fungus was 
 therefore obliged to cast about for different plants, 
 such as were specially suited to its physiological re- 
 quirements. Splendid opportunities were offered in 
 the numerous single-celled algae (Protococcus vulgaris), 
 known as " green mould," which everywhere covered 
 trees, rocks, etc. The fungus made the attempt and 
 entered into a biological relationship with this alga. 
 It is highly probable that this first relationship was of 
 a parasitic nature but the fungus soon found that these 
 minute organisms were scarcely able to supply the 
 extra food materials demanded by the attaching para- 
 site ; the climatic conditions were not sufficiently favor- 
 able, and, furthermore, the alga itself showed a slight 
 preference toward leading a parasitic life, so that the 
 fungus was considered as a very undesirable intruder. 
 
WHAT ARE LICHENS ? 31 
 
 If the organisms could in some way form an associa- 
 tion mutually beneficial they would both be enabled to 
 maintain the struggle for existence. This is what 
 actuall}'- occurred : the two organisms seem to have 
 made an agreement to assist each other. Whether 
 this was a truly altruistic motive, or whether it 
 was a case of necessity is rather difficult to deter- 
 mine. It was most likely a case of necessity ; that is, 
 the mutualistic association was compulsory in order 
 to prevent extinction. No matter which was the 
 prime motive, it remains a fact that the alga and 
 fungus finally entered into an association which was 
 mutually beneficial. This association is very different 
 from parasitism (antagonistic symbiosis), and is recog- 
 nized by scientists as a specialized form of mutualistic 
 symbiosis, designated as individualism ; the organisms 
 which enter into the formation of symbiotic associations 
 are known as symhionts. 
 
 The relation of the symbionts under discussion 
 (fungus and alga) was, in a sense, complementary : one 
 supplied what the other lacked ; there was a harmoni- 
 ous and equable assignment of labor ; each did that for 
 which nature had best fitted it. In fact, we may draw 
 therefrom a wholesome lesson. It should teach us to 
 make that our life-work for which we are by nature 
 best fitted so as to accomplish a maximum of good 
 results. 
 
 As to the division of labor in the establishment of 
 the lichen, the principal function of the fungus is to 
 supply protection ; that is, a mechanical function : the 
 chief work of the alga is to perform the function of 
 
32 GUIDE TO THE STUDY OF LICHENS. 
 
 assimilation. The fungus gave protection to the algae 
 by forming a suitable covering to prevent sudden 
 evaporation of moisture ; it also served to conduct 
 moisture and soluble food substances and supplied suit- 
 able mechanical tissues to hold the plant firmly to the 
 substratum (trees, soil, rock, etc.). The alga, due to 
 its chlorophyll, assimilated the carbon dioxide (COg) 
 of the air and formed organic compounds for the 
 use of the fungus as well as for its own use. The 
 mutual adaptations became more and more highly 
 specialized, until, after many thousands and, perhaps^ 
 millions, of generations, a large foliose lichen was pro- 
 duced, as one of the higher Parmelias. This is, in 
 brief, the probable history of the j^hylogenesis of Par- 
 melia. At different periods other lower algae entered 
 into mutualistic associations with other sac-fungi. Each 
 prototype developed in different directions, producing 
 new species and finally, perhaps, distinct genera of 
 lichens. Lichens did, therefore, not spring from a 
 single ancestral alga and fungus, they are represented 
 by a poly-ancestry. 
 
 Another remarkable thing is the fact that the agree- 
 ment formed by a given alga and fungus was by no 
 means permanent ; after a long phyletic history a given 
 lichen may have changed its alga, that is, the partner- 
 ship was dissolved and another compact entered with 
 a new alga. In many instances a new partner was 
 taken in and the old was retained, so that we find some 
 lichens with two algal symbionts. 
 
 From the above, it is evident that lichens are 
 peculiar plants ; they are the result of the mutualistic 
 
WHAT ARE LICHENS ? 33 
 
 association of a fungus and an alga, two morphologi- 
 cally distinct organisms. We shall now consider 
 somewhat more in detail the relation of lichens to both 
 algae and fungi. 
 
 II. THE RELATION OF LICHENS TO ALG^ AND FUNGI. 
 
 In the historical review we have already indicated 
 the varied positions given to lichens in the many sys- 
 tems of classification. Shortly before Schwendener's 
 wonderful discoveries lichens were treated as a distinct 
 class of plants, coequal in systematic importance with 
 fungi, algas and mosses. . Schwendener and his fol- 
 lowers unhesitatingly classified them as fungi. "Why ? 
 Because they looked upon lichens as fungi which were 
 parasitic upon algie* Reinke, de Bary and others have, 
 however, shown conclusively that it is not a truly 
 parasitic relationship ; as already indicated, it is an 
 association mutually beneficial, known as mutualistic 
 symbiosis. Schwendener's error was due principally 
 to the fact that he misinterpreted the relationship and 
 laid too much stress upon the spore-bearing structures. 
 There are no more reasons why lichens should be 
 classed as fungi than as algse. In fact, the eminent 
 scientist, Nageli, classified them as algae and Tucker- 
 man in his earlier writings designates lichens as " aerial 
 algae." The eminent French lichenologist, Ny lander, 
 had already recognized the double affinity of lichens 
 without realizing their true dual nature. In his sys- 
 tem of classification he begins with those lichens most 
 nearly resembling fungi, gradually proceeding to the 
 highest foliose and fruticose forms, then forming a 
 
34 GUIDE TO THE STUDY OF LICHENS. 
 
 descending series with those most nearly resembling 
 algae. From these considerations, it is evident that 
 the attempt to classify them either as fungi or algae 
 will lead to confusion. In agreement with Reinke, 
 Darbishire and others, we have decided to treat lichens 
 as a distinct class. The reasons for so doing will be 
 given later. 
 
 In conclusion, we will briefly describe the algae 
 which enter into the formation of lichens. The figures 
 of Plate I represent the algae surrounded by the 
 hyphal network of the fungal symbiont. The fungal 
 types cannot be represented, for the simple reason 
 that they are not known ; the knowledge that they are 
 derived from some groups of the sac-fungi must suffice 
 for the present. The general belief is that the fungi 
 which originally entered into the formation of lichens 
 no longer exist. There are, however, fungi now liv- 
 ing which resemble the fungal symbionts of certain 
 lichens ; for example, the representatives of the fungal 
 genus Hysterium closely resemble the fungal symbiont 
 of the lichen-genus Ghraphis. 
 
 I. Chlorophyce^. — The algae belonging to 
 this group are distinctly bright-green. The follow- 
 ing are the species which enter into the formation of 
 lichens, given in the order of the frequency of occur- 
 rence. 
 
 1. Cystococcus humicola. This is a unicellular alga 
 occurring in far the greater number of lichens. The 
 cells are spherical. (Fig. 1.) 
 
 2. Chroolepus umhrina. This alga forms short 
 
WHAT ARE LICHENS? 35 
 
 brandling cliains of rather oblong irregular cells bear- 
 ing brownish substances known as pyrenoid bodies. 
 (Fig. 2.) 
 
 3. Pleurococcus vulgaris. A single-celled alga of 
 rather irregular outline. It sometimes has a bluish 
 tinge. (Fig. 8.) 
 
 4' Glceocapsa polydermatica. This is also a single- 
 celled alga. It differs from the preceding in that each 
 cell is enclosed by a thick, transparent, gelatinous mem- 
 brane. (Fig. 4.) 
 
 5. Dactylococcus infusionum. A single-celled alga. 
 The cells are comparatively small and regularly ellipti- 
 cal ; they are usually associated in colonies of eight or 
 ten cells. (Fig. 7.) 
 
 II. Cyanophyce^. — The alg* of this group differ 
 from the chlorophyce^e in their blue-green color. 
 
 1. Nostoc lichenoides. This alga occurs in chains 
 of rather small cells. Each chain contains one, rarely 
 more, larger cell known as a heterocyst. Each chain 
 is enclosed by a gelatinous substance. (Fig. 3.) 
 
 2. Rivularia nitida. This alga also occurs in 
 
 o 
 
 chains, but its cells are irregular in form. Gelatinous 
 substance present. (Fig. 5.) 
 
 S. Poly coccus punctiformis. Tlie cells of this alga 
 are elliptical and occur in colonies enclosed by a com- 
 mon covering. (Fig. 6.) 
 
 4. Sirosiphon puhinatus. This is a many-celled 
 branching alga of sufficient size to be seen by the 
 naked eye. It occurs in the lichen-genus Ephebe. 
 (Fig. 9.) 
 
36 GUIDE TO THE STUDY OF LICHENS. 
 
 These brief references to the algae, with the accom- 
 panying illustrations, will suffice at present, as they 
 will again be mentioned in the discussion of lichen- 
 genera. 
 
 III. LICHENS AS MORPHOLOGICAL UNITS. 
 
 We shall now briefly summarize those characteristics 
 which distinguish lichens from other plants, fungi and 
 algae in particular. This is very necessary in the 
 present state of our knowledge of lichens, as the influ- 
 ence of Schwendener's teachings is as yet very strongly 
 felt. 
 
 Lichens macroscopically considered present such a 
 peculiar appearance that the most superficial observer 
 is led to believe that they form a group by themselves. 
 They occur in places where neither alga nor fungus 
 could exist alone. They have wonderful powers of 
 resisting extremes of temperature ; freezing only checks 
 their growth; a temperature of — 40° C. does not kill 
 them. They will resist a temperature of 60° C. for 
 an hour or more. They can tide over periods of dry- 
 ness which would invariably be fatal to either alga or 
 fungus if existing alone. 
 
 The two symbionts form a microcosmos which is en- 
 abled to perform the life-functions originally inherent 
 in both, and, in addition, the lichen has acquired new 
 structural and functional characters during its phyl- 
 ogeny. The morphological adaptations are primarily 
 for the furtherance of the function of assimilation, 
 while among fungi the structural adaptations are pri- 
 marily for the furtherance of the function of reproduc- 
 
WHAT ARE LICHENS r* 37 
 
 tion. The method of reproduction in lichens is wholly 
 different from that of fungi as well as algae. It is, 
 however, true that the spores of lichens have a close 
 morphological resemblance to the spores of certain 
 fungi, but functionally they differ widely. The spores 
 of fungi can develop into new spore-producing in- 
 dividuals, while the spores of lichens cannot produce 
 new lichens unless associated with the essential algae, 
 which proves that the fungal symbiont can no longer 
 mature independently. Some of the lichen-algae have 
 been induced to exist independently, but it is evident 
 that some cannot. Lichen-spores are simply the 
 functionally degenerate reproductive organs of their 
 fungal ancestors. 
 
 As already indicated, fungi are essentially parasitic 
 and saprophytic. Lichens have partially or almost 
 wholly lost the saprophytic and parasitic function and 
 have acquired the power of converting inorganic sub- 
 stances into organic compounds. The thallus of lichens 
 is structurally and functionally comparable to the leaf 
 of higher plants ; fungi have no thallus, nor do they 
 have any functional resemblance to the leaves of higher 
 plants. 
 
 Lichens also contain chemical compounds not found 
 in fungi or algae. Among these, lichenin (lichen-starch) 
 is the most important ; others are various acids (ever- 
 nic, cetraric, etc.) and bitter extracts, coloring sub- 
 stances, and other compounds as yet not well known. 
 
 The typical reproductive organs of lichens are the 
 soredia. These are in reality miniature thalli espe- 
 cially adapted to serve as propagative organs. They 
 
B8 GUIDE TO THE STUDY OF LICHEKS. 
 
 are formed of the elements of both symbionts and can 
 therefore develop into a new lichen. Their structure 
 and function will be more fully described elsewhere. 
 Lichens are also more long lived than fungi. The 
 majority of fungi terminate existence with the matura- 
 tion of the spores, while most lichens have an indefin- 
 itely prolonged existence. Some of the Cladonicis, for 
 example, may live hundreds of years ; the apical portion 
 continues to grow, while the basal portion dies away. 
 
 Sufficient reasons have been given to show that 
 lichens are neither fungi nor algae ; they must there- 
 fore be treated as a distinct class of plants. Other 
 characters peculiar to lichens will be mentioned later. 
 
MORPHOLOGY AND PHYSIOLOGY. 39 
 
 SECTION IV. 
 
 THE MORPHOLOGY AND PHYSIOLOGY OF 
 LICHENS. 
 
 We have already explained, in a general way, the 
 morphological structure and the functional activities 
 of lichens. We shall now enter into a somewhat more 
 special comparison of the different lichen-forms. This 
 is necessary to a better understanding of the relative 
 functional activities of lichens and their tendency in 
 the scale of evolution. We will find that the higher 
 lichens are more highly specialized as chlorophyll- 
 bearing organisms, and tluit the evolutionary ten- 
 dency is away from tlie forms resembling fungi. We 
 will find that there is a reduction in the spore-produc- 
 ing function, accompanied by an increase in the assim- 
 ilative function. 
 
 I. THE THALLUS. 
 
 The thallus of lichens is the purely vegetative portion 
 of the plant. It performs the function of assimilation, 
 and in it the phenomena of growth are actively mani- 
 fest. It is comparable to the vegetative portion of 
 other cryptogams, such as mosses and liverworts. In 
 its gross appearance and general texture, it is, how- 
 ever, very characteristic ; so that a very casual ac- 
 quaintance with lichens enables one to distinguish 
 them from all other thallophytes, as the lower flower- 
 less plants are technically known. 
 
40 GUIDE TO THE STUDY OF LICHENS. 
 
 From what has already been said of lichens, the 
 reader knows that the thallus is functionally wholly 
 different from the vegetative portion of fungi. The 
 main difference may be stated as follows : In fungi 
 the structural development and arrangement of tissue- 
 elements, of the vegetative portion, is for the special 
 purpose of furthering the function of reproduction, 
 that is, to supply a suitable structural arrangement 
 for the maturation and distribution of the spores. In 
 lichens the structural development and arrangement 
 of the tissue-elements is for the special purpose of 
 furthering the function of assimilation. 
 
 Structurally and functionally, the thallus of lichens 
 is also analogous to a foliage leaf of higher plants. 
 This becomes apparent on comparing vertical sections. 
 The upper and lower cortical layers of the thallus are 
 functionally analogous to the upper and lower epider- 
 mis of the leaf ; the algal layer of the thallus to the 
 palisade tissue of the leaf ; the medullary tissue of the 
 thallus to the spongy tissue of the leaf. The analogy 
 is, in fact, very striking, particularly between foliose 
 thalli and the ordinary flattened foliage leaves. Fru- 
 ticose thalli are analogous to leaves with " isolateral " 
 or "centric" structure. Crustose thalli are in reality 
 rudimentary foliose thalli, and are, therefore, remotely 
 analogous to ordinary foliage leaves. 
 
 For practical purposes, the thalli of all lichens may 
 be divided into three types or kinds, namely, crustose, 
 foliose, and fruticose. Their structural differences are 
 as follows : 
 
MORPHOLOGY AND PHYSIOLOGY. 41 
 
 1. The Crustose Type. 
 
 This thallus occurs in the lower lichens, that is, in 
 those in which the evolutionary specializations as 
 lichens are not yet highly marked. In its simplest 
 form it consists merely of a network of hyphae in 
 which are suspended a few algas ; it may occur on the 
 substratum, or wholly, or partially, beneath its sur- 
 face. There are no distinct layers, in fact, in many 
 instances it is almost impossible to detect any thallus 
 whatever. Such rudimentary thalli occur in the lower 
 species of Calicium^ Pyrenula, Trypethelium, Xylo- 
 grapha, Arthonia and other genera. 
 
 The higher crustose thalli are quite thick, as in Le- 
 canora, Pertusaria, the southern representatives of 
 Gh'apkis, in Pceomyces, and other genera. The sur- 
 face is often warty or the entire thallus is marked off 
 into many-sided areas or areoles and is therefore spoken 
 of as areolate. In higher crustose thalli we find the 
 tissue-elements arranged into distinct layers, as seen 
 in a vertical section. The upper layer consists of 
 hyphae and constitutes a protective covering for the 
 layer of algae just beneath. The algje are inclosed by 
 specialized branches of hyphse, spoken of as haustoria. 
 Below the algae occurs another layer of hyphae which 
 attach the thallus to the substratum and assists in tak- 
 ing up soluble food-substances. The hyphae forming 
 the upper layer, the haustoria, and the lower layer are 
 continuous, and are part of the same hyphal tissue. 
 In many instances the upper layer becomes more or 
 less distinctly cortical, thus resembling the ui)per 
 layer of foliose thalli. In fact, very often it 
 
4'2 GUIDE TO THE STUDY OF LICHENS. 
 
 is difficult to determine whether a given thallus is 
 crustose or foliose. A typical crustose thallus is 
 always closely adnate to the substratum and never has 
 a lower cortical layer ; the margin sometimes becomes 
 lobed, as in some representatives of Placodium. 
 
 It is questioned whether many of the lower crustose 
 lichens should not be classified as fungi. If a thallus 
 is present, no matter how rudimentary, it is unmistak- 
 ably a lichen ; it must be remembered that careful 
 search is often necessary to detect such rudimentary 
 thalli, as in Pyrenula and other genera. (Plates II 
 and IV.) 
 
 2. The Foliose Type. 
 
 Most of the lichens with which the amateur collector 
 will come in contact belong to the foliose type. As 
 a rule, the thallus is large, consisting of branching 
 lobes which are only loosely attached to the substra- 
 tum. In some instances the thallus is entire, varying 
 from very small, as in Dermatocarpon and Psora, to 
 very large, as in JJtr^iUcaria and Gyrophora. One 
 thing must be kept in mind and that is the fact that 
 the foliose type merges into the fruticose type in the 
 ascending series, and into the crustose type in the de- 
 scending series. The characters here given refer to 
 the more typical forms as represented by the Parmelias, 
 Physcias, Stictas, Stictinas. 
 
 If we make a vertical section of the thallus and 
 examine it under the microscope we find the following 
 structures. 
 
 1. Upper Cortical Layer. — This consists of a 
 compact tissue of short-celled hyphae. It forms a pro- 
 
MORPHOLOGY AND PHYSIOLOGY. 43 
 
 tective layer for the tissues beneath and also supplies 
 mechanical support to prevent the breaking or tear- 
 ing of the thallus due to winds and other external 
 forces. The upper portion of this layer is sometimes 
 colored, due to a deposit of acid crystals. The func- 
 tion of this colored substance is, perhaps, twofold : it 
 probably -modifies the influence of sunlight, and keeps 
 away animals which feed upon lichens, such as snails. 
 The thickness of this layer varies greatly in different 
 lichens. The layer is often not uniform in thickness, 
 even in the same plant; for example, in Peltigera it is 
 alternately thicker and thinner, and shows a remark- 
 able double adaptation — to supply the required mechan- 
 ical support, and at the same time allow the algae to 
 approach nearer the surface for the purposes of greater 
 chlorophyllian activity (carbon assimilation). 
 
 2. Algal Layer. — This lies beneath the layer just 
 described, and consists of a loose network of hypha? in 
 which the algae are suspended. It is the layer in 
 which carbon assimilation is carried on. Certain 
 hyphal branches, the haustoria, enclose and even pen- 
 etrate the algae, and take from them the assimilated 
 food-substances required by the fungal symbiont, while 
 the alga in return receives water and certain soluble 
 food-substances from the fungal symbiont. 
 
 3. Medullary Layer. — This consists of a very loose 
 network of hyphae. It contains air, and therefore the 
 carbon dioxide required to carry on the function of as- 
 similation. The thickness of this layer varies con- 
 siderably. 
 
 ^. Lower Cortical Layer. — When present it re- 
 
44 GUIDE TO THE STUDY OF LICHENS. 
 
 sembles the upper cortical layer, usually it is defi- 
 cient, and in a number of genera it is wholly wanting. 
 When wanting, its place is taken by a tissue of hyphae 
 which extend longitudinally. From the lower surface, 
 whether cortical or not, the rhizoids extend. These are 
 hyphae, either single or in groups, which grow verti- 
 cally downward into the substratum ; they sometimes 
 remain aerial and perhaps serve to retain moisture or 
 to keep off crawling insects and snails. Usually the 
 rhizoids are colored black. The cilia at the marsfin of 
 many foliose thalli are morphologically and function- 
 ally analogous to aerial rhizoids. (Plates II, III and 
 IV.) 
 
 3. The Fruticose Type. 
 
 The fruticose thallus differs from the preceding in 
 that the lobes of the thallus are distinctly ascending 
 and are not attached to the substratum. The entire- 
 plant is attached at a central or basal point known as 
 the umbilicus. It must, however, be remembered, that 
 the umbilicus is also present in some foliose thalli, as 
 Umbilicaria and Gyrophora. The umbilicus consists of 
 a hyphal tissue, and is analogous to the roots of trees, 
 holding the plant firmly attached to the substratum 
 and taking therefrom moisture and soluble food-sub-, 
 stances. 
 
 The lobes of the thallus are usually much branched, 
 and vary from distinctly flattened to cylindrical. The 
 highest and most perfect type is, no doubt, represented 
 by Usnea harbata. 
 
 In the flattened fruticose thallus we find the follow- 
 ing tissues, which are essentially like corresponding 
 
MORPHOLOGY AND PHYSIOLOGY. 45 
 
 tissues of the foliose thallus : 1. Upper or inner corti- 
 cal layer ; 2. Upper or inner algal layer ; 3. Medullary 
 layer ; 4. Lower or outer algal layer ; 5. Lower or 
 outer cortical layer. Rhizoids are not present ; cilia 
 may occur, as in Cetraria islandica. 
 
 In the cylindrical fruticose thalli, all the tissue-ele- 
 ments are arranged in a cylindrical fasliion. The cen- 
 tral portion may be hollow, as in Cladonia and Pilo- 
 phoron, or solid, as in Usnea. This arrangement of 
 tissue-elements is in accordance with mechanical prin- 
 ciples, giving the required support to the usually large 
 thalli. (Plates II and IV.) 
 
 n. THE APOTHECIA. 
 
 The apothecia are the spore-bearing structures de- 
 veloped in or upon the thallus. They are structurally 
 very similar to the spore-})roducing organs of fungi 
 (Ascomycetes, sac-fungi) but functionally, the similar- 
 ity is not so close. Among fungi, each spore is cap- 
 able of developing into a mature spore-producing 
 plant; that is, it is the true reproductive element of 
 the fungus. In lichens it is essentially different; here 
 the spore cannot develop into a new spore-produc- 
 ing plant for the simple reason that the spore 
 and its product represents only a part of the lichen- 
 autonomy ; that is, the germinating spore must be asso- 
 ciated with the requisite algae before a new lichen can 
 develop. This difference is very important and should 
 be kept in mind when comparing lichens and fungi. 
 The spores of lichens are functionally degenerate, re- 
 productive organs derived from the fungal ancestor 
 
46 GUIDE TO THE STUDY OF LICHENS. 
 
 which entered into the formation of the lichen or 
 lichen-group under consideration. The typical repro- 
 ductive organs of lichens are the soredia, which shall 
 receive consideration in another chapter. 
 
 The apothecia have undergone certain changes dur- 
 ing the phylogenetic history of the lichen. These 
 changes are primarily for the furtherance of the func- 
 tion of assimilation, rather than that of spore-formation. 
 This is naturally to be expected since the spores are 
 of little value as reproductive organs. Many of the 
 higher lichens are constantly sterile. In some, the 
 original apothecial structure has been converted into 
 an assimilating organ, that is, a thallus. The vertical 
 thallus of the Gladonias, usually known as the pode- 
 tium, is doubtless such a modified apothecial structure. 
 Again, the " cup apothecia " of some lichens have be- 
 come greatly expanded, and contain within their in- 
 terior algae, thus acting as assimilating organs. In 
 others, particularly the lower forms, the apothecia re- 
 tain the structural characters of their fungal ancestors ; 
 that is, they do not bear algae, and hence do not take 
 part in the function of assimilation. Upon the pres- 
 ence or absence of algae are based the distinctions into 
 fungal and thalline apothecia. 
 
 1. The Fungal Type. 
 
 This apothecium is in all respects similar to the 
 apothecium of an Ascomycetous fungus. The algae of 
 the algal layer of the thallus do not enter into its 
 formation. It may be cup-shaped, as in the Discomy- 
 cetes, or immersed, as in the Pyrenomycetes. In the 
 
MORPHOLOGY AND PHYSIOLOGY. 47 
 
 former case, the following structures are discernible in 
 a vertical section. The uppermost layer forming the 
 disk, consists of the spore-sacs and paraphyses. The 
 former are specialized hyphae which contain the spores ; 
 the latter are also specialized hyphae, placed vertically, 
 like the spore-sacs, but are much more slender and do 
 not contain spores. This layer is known as the thecium ; 
 the spore-sacs are also known as thecce or thekes. The 
 term spore-sacs is, however, preferable, as it expresses 
 more clearly what they are. The upper ends of the 
 paraphyses are frequently colored, as brown, black, 
 scarlet, yellow, etc., giving the disk its characteristic 
 color, as discerned by the naked eye. Below the the- 
 cium occurs the hypothecium, which consists usually, 
 of closely united hyphae, generally extending at right 
 angles to the spore-sacs and paraphyses. This tissue 
 is more or less cup-shaped ; in the Pyrenomycetous 
 type, it formes a sphere, enclosing the thecium. In 
 some cases it is convex, rather than concave or cup- 
 shaped, as in Cladonia and Bceomyces. 
 
 If we have made our section from near the margin 
 of the cup, we will find the following additional tis- 
 sues. 1. Medullary tissue similar to, and continuous 
 with the medullary tissue of the thallus. 2. Cortical 
 tissue similar to and continuous with the upper corti- 
 cal layer of the thallus. Sometimes this layer is not 
 cortical. (Plate IV.) 
 
 2. The Thalline Type. 
 
 This differs from the foregoing in that the algal 
 layer of the thallus extends into the apothecium, 
 
4^ GUlDE to TrtE STUDY OF LICHENS. 
 
 usually forming two layers ; one imnaediately under- 
 neath the hypothecium, and the other just above the 
 lower cortical layer of the apothecium. The algae may 
 approach quite to the margin of the cup, or they may 
 extend only a part way up. In fact, there are all 
 gradations, from the purely fungal type to the most 
 highly developed thalline type as it occurs in the 
 Parmelias and in Usnea. In general it may be stated 
 that the fungal type occurs in the lower lichens, while 
 the thalline type occurs in the higher lichens. There 
 are, however, important exceptions to this rule. Figs. 
 1 to 5 of Plate IV will serve to illustrate the differ- 
 ences between the types just discussed. 
 
 III. ACCESSORY STRUCTURE. 
 
 The thallus and apothecia constitute the most im- 
 portant lichen-structures ; there are, however, a num- 
 ber of other structures which occur on the thallus, 
 and which are of more or less importance in the lichen- 
 economy, and for that reason it is well that the student 
 should be somewhat familiar with them. They are 
 here discussed in the order of their importance : 
 
 1. The Soredia. 
 
 Examination of the upper surface of the thallus of 
 many lichens reveals patches of a powdery or mealy 
 substance. These patches may be circular or linear, 
 especially along the margin of the thallus. If some 
 of this powder is placed under the microscope and 
 examined, it is found to consist of small irregular 
 bodies made up of a hollow network of hyphae, in the 
 
* MORPHOLOGY AND PHYSIOLOGY. 49 
 
 interior of which algae occur. Each body is in reality 
 a miniature thallus, and is capable of developing into 
 a new lichen should it find a suitable lodging-place. 
 It is the true propagative organ of lichens. The 
 majority of lichens depend almost wholly upon this 
 method of reproduction. 
 
 It is well to bear in mind that lichens are also 
 propagated in a purely vegetative way ; that is, a portion 
 of a lichen-thallus, or even the entire thallus, may be 
 torn away and carried to a new locality, where a por- 
 tion of it will develop into a new lichen. Some lichens 
 also possess what may be designated as continuous re- 
 juvenescence ; that is, there is continuous apical growth, 
 accompanied by a continual dying away of the older 
 portion. Tliis phenomenon occurs typically in the 
 higher Cladonias as well as in Thamnolia, and is also 
 met with in the higher foliose lichens, as Parmelia. 
 The central, hence older, portion dies away, while the 
 margin continues to grow, producing an appearance 
 not unlike the "fairy rings" of certain mushrooms. 
 Nevertheless the soredia constitute the most important 
 means of propagating lichens. They are developed 
 from the algal layer of the thallus, finally pushing 
 their way through the upper cortical layer to the ex- 
 terior. Each body is known as a soredium ; a collec- 
 tion of them forming one of the patches above men- 
 tioned is designated as a soralium, plural soralia. 
 
 2. The Cyphellce. 
 
 Upon examining the lower surface of the thallus of 
 a Sticta or Stictina there will be found a number of 
 
50 GUIDE TO THE STUDY OF LICHENS. • 
 
 lighter-colored specks, somewhat smaller than a pin- 
 head ; these are the cyphellce and are functionally anal- 
 ogous to the stomata or breathing pores of true foli- 
 age leaves. Structurally there is no resemblance ; 
 they are simply breaks in the lower cortical layer, 
 filled in by a loose secondary cortical tissue. Upon 
 examining them with a hand-lens, it will be found 
 that they are of two kinds : one which appears as a 
 depression, that is, concave ; the other is somewhat 
 protruding or convex. They occur only in the genera 
 indicated. 
 
 3. The Cephalodia. 
 
 These are wart-like outgrowths, usually occurring 
 on the upper surface of the thallus. Sometimes they 
 also occur on the lower surface, as in Sticta Oregana. 
 They are simply neo-formations in the tissue of the 
 thallus, induced by a foreign alga. They occur upon 
 various lichens, but are, perhaps, most common among 
 the Peltigeras and Stictas. In Peltigera aphthosa 
 they are very numerous and are about the size of a 
 pin-head. In Sticta Oregana they vary from very 
 small to nearly the size of a pea.' These two plants 
 also typify the two kinds of cephalodia. In Peltigera 
 they develop upon the thallus, while in Sticta they de- 
 velop within the thallus. Nothing definite is known 
 regarding their origin and function. 
 
 Jf.. The Spermagonia. 
 
 These are very minute cup-shaped structures, im- 
 mersed in the upper surface of the thallus. To the 
 naked eye they appear as minute black specks. Noth- 
 
MORPHOLOGY AND PHYSIOLOOxY. 51 
 
 ing definite is known regarding their function. Some 
 investigators suppose them to be tlie male reproductive 
 organs of lichens; others are inclined to look upon 
 them as parasitic fungi. Many lichenologists have 
 made the sad mistake of considering them as of great 
 importance in classification ; as such they are of little 
 significance, because they are too variable in their oc- 
 currence, and too closely similar in structure. The so- 
 called Pycnidia are closely related to the Spermagonia. 
 It is not at all likely that the reader will care to 
 make any careful examination of the spermagonia. 
 Should he, however, do so, he will find that each sper- 
 magonium resembles a small apothecium. In place of 
 the thecium occur hyphal branches {sterigmata) on 
 which minute acicular or rod-shaped bodies {sper- 
 matia) are borne. 
 
52 GUIDE TO THE STUDY^ OF LICHENS. 
 
 SECTION V. 
 
 THE OCCUERENCE AND DISTRIBUTION OF 
 LICHENS. 
 
 The actual number of species of lichens occurring 
 on the entire globe is not known. According to Ny- 
 lander, about 1,500 species were recognized in 1858 ; 
 between 4,000 and 5,000 species and varieties were 
 recognized in 1892, according to Hue. The United 
 States contains perhaps between 800 and 1,000 species. 
 It must, however, be remembered, that all estimates 
 are more or less unreliable. Many years of careful 
 study are required in order to get at reliable data re- 
 garding the actual number of lichen-species. 
 
 I. THE LATITUDINAL AND ALTITCDINAL DISTRIBU- 
 TION OF LICHENS. 
 
 Lichens extend to the far north, where, with a few 
 mosses, they form the most advanced outposts of vege- 
 table life ; they extend within a short distance of the 
 northern snow limit. In the high arctic regions they 
 constitute the characteristic flora of the country. Here 
 they occur mostly as earth-lichens and rock-lichens, dif- 
 ferent species growing in close association, forming what 
 are technically known as " lichen-tundra." The great 
 majority of species belong to the genera Cetraria, 
 Gladonia, and Evernia, The cause for their occur- 
 
OCCURRENCE AND DISTRIBUTION. 53 
 
 rence as earth-lichens is quite evident, as scarcely any- 
 other substrata exist; trees, fences, and the like 
 being wanting. Jn the more temperate regions we 
 find earth-lichens, rock-lichens and a considerable num- 
 ber of tree-lichens. In the tropics tree-lichens pre- 
 dominate, owing to the greater competion for space. 
 The richness of vegetation of all sorts, trees among the 
 rest, makes it evident that vegetable substrata are, in a 
 sense, forced upon the lichens. In fact, the intimate 
 associations of plants with plants and of animal with 
 plants, etc., are much more prevalent in the tropics, 
 for similar reasons. The great struggle for existence 
 necessitates the establishment of mutual adaptations 
 as well as antagonism or parasitism. 
 
 Some lichens have a limited range, wliile others are ' 
 truly cosmopolitan, such as Oladonia rangiferina, 
 Usnea barbata, Lecanora subfusca and others. As to 
 substrata, some species are limited to a given rock- 
 formation, while others occur upon different rock- 
 formations as well as upon trees, and even soil, such 
 as many of the Parmelias and Physcias. Trees (bark), 
 rocks and soil are the principal substrata for lichens; 
 they are also common upon dead (not rotten) wood, 
 such as fences, roofs of buildings, etc. Exceptionally 
 they have been found growing upon rotten wood, 
 old leather, bones, glass, iron railings, etc. Some are 
 truly parasitic upon the green leaves of plants in the 
 tropical and subtropical regions. 
 
 Crustose lichens very frequently encroach upon each 
 other, the stronger and more rapidly growing species 
 finally spreading over and destroying the less resist- 
 
54 GUIDE TO THE STUDY OP LICHENS. 
 
 ing species. The same thing occurs among foliose 
 and fruticose lichens. A great many lichens show a 
 decided preference for mosses, over which they spread 
 in considerable profusion, finally killing the mosses, 
 not so much as the result of drawing any nourishment 
 from them, but rather as the result of mechanical in- 
 terference and the shutting off of air and sunlight. 
 
 In general it may be stated, that lichens occur plen- 
 tifully from the northern limit indicated to the tropics. 
 Some lichens are essentially southern, others northern 
 or western. Only a very few are typically eastern. 
 
 It is quite important that the collector should have 
 some knowledge of the vertical distribution of lichens ; 
 this will avoid much waste of time in searching for 
 lichens in places where they do not occur. For exam- 
 ple, Gyrophoras and Umhilicarias do not occur at 
 slight elevations ; in fact, the lowlands yield only com- 
 paratively few lichens. As a rule, lichens which occur 
 at low levels in the arctic regions also occur at high 
 altitudes in the warmer or tropical regions. 
 
 As already indicated, mountainous timber regions 
 yield the most numerous and finest specimens of 
 lichens ; prairies and open lowlands yield the poorest 
 and fewest. It also seems that there is a narrow belt 
 in the immediate vicinity of the coast which is deficient 
 in lichens ; this is perhaps due to excessive moisture, 
 which is detrimental to their existence. We have 
 elsewhere indicated that lichens flee from civilization. 
 The reasons for this are not definitely known ; it is 
 very likely due to the dust and smoke (impure atmo- 
 sphere) of the cities ; they require pure air for their 
 
OCCURRENCE AND DISTRIBUTION. 55 
 
 existence. One need, therefore, waste no time in 
 looking for a rich harvest of lichens in city parks, 
 along much-travelled roadsides, in woods that are fre- 
 quently run over by cattle, sheep, and oth'^r animals. 
 Seek the highest and wildest hills in your locality; if 
 there are none, search through the timber-lands; if 
 that particular locality is without hills, mountains, and 
 timber, devote yourself to the orchard, the fences, old 
 buildings, trees along roadsides, etc. Make the best 
 of your locality and make excursions to other more 
 favorable areas. Further particulars in regard to the 
 occurrence of lichens will be given in the description 
 of genera and species. 
 
56 GUIDE TO THE STUDY OF LICHENS. 
 
 SECTION VI. 
 
 LICHENS AND THE NATURALIST. 
 
 It is hoped that, from the consideration of the pre- 
 ceding chapters, the reader has obtained a fair knowl- 
 edge of the true nature of a lichen, so that there will 
 be no difficulty in recognizing at least the higher forms. 
 The origin and structure of lichens has been explained, 
 so that there is no excuse for confounding them with 
 fungi or mosses, or to designate them as " dead things," 
 "excrescences," or "nothing much." Each lichen 
 will bring up some association, with the history of 
 its evolution, its treatment in the hands of the botan- 
 ists of the past, its uses in the arts and in medicine, its 
 relation to other plants, its work in nature, etc. All 
 this will serve as food for thought while on a collecting 
 trip. It is now our purpose to indicate briefly how 
 to collect, study and preserve lichens. 
 
 I. THE COLLECTION OF LICHENS. 
 
 Lichens may be collected all the year round, but 
 there are seasons which are more suitable than others ; 
 such as late in the summer and in the autumn, because 
 then the thalli and the apothecia are at their best. 
 The great majority of lichens live from year to year, 
 and can, therefore, be collected at any time ; some be- 
 gin development and mature in one season, such as the 
 
LICHENS AND THE NATURALIST. 57 
 
 Collemas ; these in particular should he collected in ' 
 the fall. 
 
 Having decided upon the most favorable season for 
 collecting, we find that there are days and portions of 
 a day which are particularly suited for this work. Just 
 after a rain lichens show their brightest colors and 
 become greatly enlarged, owing to the absorption of ' 
 water. At this time the foliose and fruticose lichens 
 are not in the least brittle ; they can be bent or rolled 
 without any danger of breaking them. In the morn- 
 ing and early forenoon is the next best time in which 
 to collect. The worst period of a bright day is at noon 
 or in the early afternoon between twelve and three 
 o'clock. Quite early in the evening lichens again take 
 up moisture and lose their brittleness. In the case of 
 crustose rock and tree-lichens, the moisture or dryness 
 of the thallus is of no consequence ; they might, there- 
 fore, be collected during dry weather, or during the 
 dry periods of the day. Foliose and fruticose rock- 
 lichens lose their moisture first, next come the tree- 
 lichens, and last of all the lichens of the soil. 
 
 No expensive or complicated outfit is needed to col- 
 lect lichens ; cumbersome and not absolutely necessary 
 traps should not be carried about. We will briefly 
 describe the equipment of a collector who intends to 
 put in a day's work in a locality where lichens are quite 
 plentiful. As to the clothing to be worn, it need not, 
 of course, be explained that it is not a dress-suit affair; 
 put on good stout old clothing, a broad-brimmed felt 
 hat, and stout shoes with thick soles. It is well and 
 advisable to carry along a lunch, and, above all, make 
 
58 GUIDE TO THE STUDY OF LICHENS. 
 
 plans to enable you to secure a drink of water ; if you 
 know of a spring, that is just the thing, keep it in mind 
 and head for it at the appropriate time ; if no spring 
 exists in the locality, head for a farm-house. Never 
 drink out of small brooklets, especially in inhabited 
 localities : there is always more or less danger of be- 
 coming infected with some disease germs, or perhaps 
 some intestinal parasite. The collecting outfit may 
 be divided into three groups, as follows : 
 
 1. Contrivances for carrying lichens. 
 
 2. Mechanical aids in collecting. 
 
 3. Aids to a temporary study of lichens. 
 
 1. The most convenient contrivance for carrying 
 lichens is the botanist's collecting-can, more technically 
 known as a vascuhim. This can, however, only be 
 secured ready-made from dealers in botanical supplies. 
 Any tinsmith can make one to order, for perhaps $1.00, 
 or $1.50, provided it is explained to him how to make 
 it. The most convenient box for collecting lichens 
 should be rectangular, with corners rounded, made of 
 heavy tin. It has a door at the side or top. It should 
 have a coat of black japan on the outside to prevent 
 the annoying reflection of sunlight. The size of the 
 box can be left to the taste and needs of the individual. 
 If a botanical collecting-box is not convenient, an old 
 hand-satchel will do very well, in fact, in many re- 
 spects it is superior to the tin box. 
 
 It is supposed that the collector intends to bring 
 home crustose rock-lichens and crustose tree-lichens 
 as well as foliose and fruticose lichens. The rock- 
 specimens should be wrapped in paper separately, to 
 
LICHENS AND THE NATURALIST. 59 
 
 prevent abrasion, and placed in tlie bottom of the vas- 
 culum or satchel ; on top of these place tlie bark-lichens, 
 and finally, uppermost, the foliose and fruticose' 
 lichens. Or the rock and bark-lichens may be placed 
 in the box as indicated, while the large lichens may be^ 
 placed in a special folio made of two broad thhi boards 
 or heavy pasteboard, with a back and suitable handles. 
 The lichens should be spread between folded sheets of 
 paper (newspaper or any other), care being taken not 
 to crush them while dry ; if dry, moisten them, when . 
 they may be pressed in any position without injury. 
 
 2. The collector will require the following instru- 
 ments to aid him in securing specimens : a. A good, 
 large jack-knife for securing bark-lichens, especially 
 the crustose forms. This should be quite sharp and 
 may be carried in the pocket, b. A hammer of 
 medium size, and a cold-chisel of medium size for 
 securing crustose rock-lichens. These might be car- 
 ried in a leathern pouch, such as is used by geologists, 
 which would also serve to carry the rock-specimens. 
 c. A carpenter's chisel, or a table-knife, will be found 
 convenient for removing large foliose lichens from 
 rocks, fences and trees. 
 
 It now only remains to give some general advice as 
 to where and how to collect. From what has been 
 said of the distribution of lichens, it is known that 
 mountainous and wooded districts yield the richest 
 harvest ; thickly populated and open districts are the 
 poorest in the variety of fine specimens. It is never 
 advisable to proceed from a poor district to one rich 
 in species. It is only a waste of time' and energy to 
 
60 GUIDE TO THE STUDY OF LICHENS. 
 
 collect poor, scrawny specimens, which will be cast 
 aside as better material is found. It will, of course, 
 not be necessary to urge the advice not to begin the 
 collection with the more insignificant crustose forms ; 
 the beginner will only too gladly leave these alone. 
 For some time attention should be devoted to the 
 larger foliose and fruticose lichens and to collect fer- 
 tile material in so far as that is possible. It must, 
 however, be remembered that some lichens rarely or 
 never bear apothecia. These may be collected and 
 retained until the fertile forms have been studied, 
 when little difficul ty will be found in classifying them, 
 at least generically. 
 
 lichens occur in nearly all places where there is 
 ii not too much constant moisture and shade. They are 
 most numerous on the " weather-side " (northern ex- 
 posure) of trees, fences, old roofs and stone walls. 
 Travellers and hunters have time and again utilized 
 this knowledge to guide them in their journeys. Large 
 specimens of lichens occur on the bleakest rock ; fine 
 specimens of Cladonia occur on the soil in compara- 
 tively open ground ; some large foliose species (Pelti- 
 ffera) occur on the soil in shaded places. Bceornyces 
 J roseus, with its pink' apothecia, which is quite striking 
 in appearance although it is one of the crustose forms, 
 also occurs on the soil. 
 
 From a study of the table of the continental range 
 of lichens one can obtain some idea as to what genera 
 may possibly be met with in a given locality. A col- 
 lector in the eastern, southern, or central states need 
 waste no time looking for Rocella tinctoria^ as this 
 
LICHENS AND THE NATURALIST. 61 
 
 lichen occurs on the Pacific coast. Graphis, Arthonia 
 and a few other genera are largely southern, etc. It 
 is also well to fix in mind their altitudinal distribution, 
 80 that no time will be wasted in looking for lichens 
 in the lowlands which occur only at considerable eleva- 
 tions. 
 
 In a general way it may be advised to begin the 
 collection with the highest altitudes and to descend 
 gradually, carefully examining trees, rocks and soil. 
 Rocky ledges at high altitudes will be covered by large 
 foliose and fruticose lichens, as well as a host of crus- 
 tose forms. Some of the Parmelias may be several 
 feet in diameter. If the rock is not too rough the 
 lichen can be peeled off readily : begin on one side, 
 with the carpenter's chisel, or the table-knife, gradually 
 loosen it and roll the edge over, keep on, slowly and ^ 
 patiently, and you will succeed in removing it entire ; 
 if the plant is dry and brittle it will be necessary to 
 moisten it with water before trying to remove it. 
 After it is removed lay it flat between two sheets of 
 paper and place it in the portfolio, or leave it rolled 
 up and put it in the collecting-box. Umbilicarias, 
 Gyrophoras, Stereocaulon, Gladonia and some others, 
 will occasion no trouble in removing them from rock, 
 as they are only loosely attached. If they are dry 
 and brittle it is well to moisten them before handling 
 much. Some difficulty will be encountered in remov- 
 ing foliose lichens from the bark of trees ; usually only 
 fragments can be obtained. The fruticose lichens, no 
 matter where they occur, can be collected with but 
 little difficulty. Crustose bark-lichens require the 
 
y^ 
 
 62 GUIDE TO THE STUDY OF LICHENS. 
 
 aid of the jack-knife or perhaps the carpenter's chisel 
 and the hammer. Crustose rock-lichens require the 
 use of the cold-chisel and the hammer. If the rock is 
 stratified, or " chips " easily, no difficulty will be en- 
 countered, but if the rock is not stratified, for example, 
 granite, the chisel is of little value ; the best that can 
 be done is to knock off fragments of the rock from 
 the corners ; it will be impossible to get thin specimens. 
 
 Each specimen, as it is collected, should be carefully 
 examined with a lens carried for that purpose ; search 
 for apothecia, observe the color, size, and general 
 contour ; where does it grow — on rocks, trees, or soil ? 
 the altitude, locality, etc. These points, and others 
 which may seem interesting, should be entered in a 
 note-book ; they will be found very useful in the sub- 
 sequent study of the specimen. A leisurely collector 
 may take with him a guide to the study of lichens and 
 determine at least some of the material collected, but 
 this is not at all urged, as the final studying of the ma- 
 terial is to be done at home. 
 
 Collected material requires no immediate care. It 
 may be kept tied up in bundles until wanted for study, 
 or until it is intended to prepare the specimens for 
 mounting. One thing must, however, be remembered : 
 do not stow away large packages of lichens in a moist 
 place, because in a few days they will be covered over 
 with mould, thus ruining the specimens. Another 
 thing to be guarded against, is not to keep thoroughly 
 wet specimens wrapped in bundles for more than a few 
 hours, as many species will change color, the result of 
 chemical processes ; this is particularly true of some 
 
LICHENS AND THE NATURALIST. 63 
 
 of the Parmelias. In view of these facts, it would, 
 therefore, be advisable to expose the collected material ' 
 to sunlight until they are quite dry ; they can then 
 be safely stored away for an indefinite period of time. 
 
 II. THE STUDY OF LICHENS. 
 
 About the first thing to be done with the collected 
 material is to study it critically, with a view to deter- 
 mining the species. This can best be done at home, 
 where the necessary apparatus and conveniences may 
 be employed. It is also taken for granted that no 
 previous experience has been had in identifying lichens. 
 
 Place the collected material on a convenient table; 
 now sort the lichens into heaps, placing those that 
 look alike together. Compare them carefully as to 
 color, branching, size, and form of the apothecia, etc. 
 Make liberal use of the pocket lens, and have the field 
 note-book at hand for reference. If the specimens are 
 dry and brittle moisten them by dipping in a basin of 
 water ; this will also restore their natural color. The 
 number of heaps indicates approximately the number 
 of species collected. 
 
 The next step in the procedure is to select one of 
 the heaps of which the specimens have well-developed 
 apothecia. It is preferable, in most instances, to begin 
 with fruticose forms, only it must be remembered that 
 many of them are normally sterile, that is, tliey are 
 without apothecia. 
 
 The next thing to be done is to determine the fam- 
 ily to which the plant under consideration belongs. » 
 This can be accomplished with the aid of the key and 
 
64 GUIDE TO THE STUDY OF LICHENS. 
 
 diligent study of the description of families. The 
 method of procedure in the identification of the 
 genus depends somewhat upon whether or not a com- 
 pound microscope is available. If a microscope is at 
 hand the genus may be determined from the examina- 
 tion of the spores, and incidentally, also, the algae. 
 All that is necessary is to take very minute bits of 
 the thallus and apothecium, tear them apart thoroughly, 
 mount in water and examine. If the fragments are 
 still too thick, carefully press upon the cover-glass, ac- 
 companying the pressure with a rotary motion of the 
 finger ; this will separate the tissue-elements sufficiently 
 to permit their being seen distinctly. If no microscope 
 is at hand, the only thing that remains to be done is 
 to do the best you can without it ; the " artificial 
 key " is especially prepared for those who are without 
 / a compound microscope. No attention need be paid, 
 in this latter case, to spore-characters and the alg£e ; 
 make use of the family-characters and generic charac- 
 ters given in Part II. 
 
 After the genus is determined, it only remains to 
 identify the species. This is done by referring to 
 the descriptions of the species belonging to that genus. 
 The beginner must not feel discouraged should he be 
 unable to name all the species collected, it is not ex- 
 pected of him. The unnamed specimens should be 
 kept for future study, or they may be submitted to an 
 expert for identification. It is well to bear in mind 
 that the expert cannot afford to do this work gratis ; 
 in perhaps most instances he will be satisfied with a 
 duplicate set 
 
LICHENS AND THT: NATURALIST. 65 
 
 It would also be advisable for the beginner to pur- 
 chase a set of lichens already named by some good 
 autliority on lichens. A set of from fifty to one hun- 
 dred lichens typical of the United States can be had 
 for from five to ten dollars. These lichens would be 
 found very useful as helps in the identification of most 
 genera and species. 
 
 This general advice is intended to point out the way 
 as to the procedure in the identification of species. 
 Great patience is necessary. Do not expect impos- 
 sibilities ; if you determine one out of every six 
 species collected you have done well ; if you deter- 
 mine them all you are a genius and should make lichen- 
 ology your life-work. In any case the mere name adds 
 little to our appreciation of the lichen ; it is the 
 knowledge of its true relation to other things which 
 makes it interesting. 
 
 III. THE PRESERVATION OF LICHENS. 
 
 Fortunately lichens are very easily preserved ; they 
 require less care than any of the other groups of plants. 
 Some skill is, however, necessary to prepare a really 
 fine collection, or herharirim, as it should be more tech- 
 nically called. Some collectors will no doubt find use 
 for lichens for decorative purposes, but the prime ob- 
 ject of the great majority of lichenologists in making 
 collections will be to arrange them in some suitable 
 manner, with the view to accumulating a lichen-herba- 
 rium of fine, large, well-preserved, well-mounted speci- 
 mens. With this in mind, we shall consider especially 
 the preservation of the foliose and fruticose lichens. 
 
66 GUIDE TO THE STUDY OF LICHENS. 
 
 The collected material usually has clinging to it 
 various foreign substances, such as soil, leaves, twigs, 
 moss, particles of bark and decayed wood, etc. It is 
 desirable to remove these as far as possible. A little 
 experience in cleaning them will teach how this can 
 be done best and most expeditiously. Much of the soil, 
 sand, and other substances can be shaken out ; wash- 
 ing and rinsing in plenty of water will readily remove 
 dust and dirt. Leaves, moss and twigs can be picked 
 out with a pair of tweezers. Each specimen should 
 be carefully cleaned. If the specimens have been 
 washed, lay them where the water can drain off. All 
 v^ specimens should be moistened before they are pressed, 
 but it must be remembered that there should be no ex- 
 cess of water present. 
 
 The next step in the procedure is to dry and press 
 the cleaned specimens. For this purpose, sheets of 
 blotting-paper are necessary, or, better still, the regu- 
 lation dryers used by botanists. Place one of the 
 sheets of blotting-paper or dryer on a piece of board 
 or on a table, on this place a sheet of paper (news- 
 paper will answer very well). Now take the moder- 
 ately dry specimens (they must be sufficiently moist to 
 be thoroughly soft and pliable) and arrange them as 
 you wish them to appear in the collection. If a foliose 
 lichen, of course the entire thallus is simply laid flat. 
 If fruticose, arrange the branches as artistically (natu- 
 rally) as possible. Cover the entire sheet, but do not 
 place specimens over each other. Place another sheet 
 of newspaper over the lichens, followed by one or two 
 dryers, then begin with the arrangement of another 
 
LICHENS AND THE NATURALIST. 67 
 
 layer of lichens, and continue this process until the 
 entire collection of fruticose and foliose lichens is 
 placed between dryers. On top of the entire pile 
 place a board with a weight of from 20 to 25 pounds. ^ 
 For the first two days the specimens with the two 
 sheets of newspaper should be transferred to dry dryers 
 twice daily. For this purpose it is necessary to have 
 two sets of dryers ; the moist ones should be exposed 
 to the sun while the others are in use. For the next 
 three days they need be changed only once daily. At - 
 the end of five days the lichens are, no doubt, perfectly 
 dry; they will be found permanently flattened and 
 ready for mounting. 
 
 Lichens, like all other botanical specimens, should 
 be mounted on the regulation mounting sheets of • 
 heavy glazed white paper. Fasten the specimens to 
 the paper by means of glue (fish-glue). Arrange the 
 specimens uniformily, but never place more than one 
 species on a sheet. With foliose lichens, it is desirable 
 to place two specimens side by side, one showing the . - 
 lower surface and the other the upper surface. If the 
 specimens are large, one will be enough to place on a 
 sheet ; if small, as many as five or six may be glued on. 
 In this case it is advisable to select specimens from 
 widely different latitudes and altitudes. 
 
 As soon as the specimens are glued on the sheets 
 they should again be placed between the sheets of . ^ 
 newspaper and dryers, with pressure applied until the 
 glue is perfectly dry, when they are ready to be placed 
 in the herbarium with other specimens. 
 
 If mounting paper is not at hand, the specimen may 
 
68 GUIDE TO THE STUDY OF LICHENS. 
 
 be glued in a scrap-book or a blank book of a similar 
 nature. In this case it is advised to follow some system ; 
 that is, place the specimens belonging to the same genus 
 on successive pages and arrange the genera in the order 
 they are given in the guide. If one scrap-book is filled, 
 get another of the same kind and proceed as before. 
 For the amateur the scrap-book method will prove 
 most satisfactory ; but if it is intended to accumulate 
 an extensive or approximately complete collection, it 
 is advisable to use the mounting sheets. 
 
 The specimens may also be glued on small pieces of 
 heavy paper (bristol-board will answer very well). 
 / ' Later these sheets with the specimens may be glued 
 on the regulation mounting paper, or in the scrap-book. 
 In all instances space should be left to paste the label 
 at the lower right-hand corner, 
 
 Crustose bark-lichens and the smaller specimens of 
 crustose rock-lichens may be mounted at once. Re- 
 move unnecessary bark and rock, and make them as 
 presentable as possible before mounting. Usually, 
 rock-specimens are too heavy to be mounted on paper; 
 they had best be kept in small pasteboard boxes, or 
 in the paper pockets about to be described. In any 
 case it is not at all likely that the beginner will care 
 to make an extensive collection of rock-specimens. 
 
 Lichens may also be put up in paper pockets, especially 
 those intended for exchange. A paper pocket is noth- 
 ing more or less than a piece of heavy paper (manila 
 or similar paper) folded in such a manner as to hold 
 the specimen. They may be made as follows : Secure 
 the right sort of paper, and cut or have it cut into 
 
LICHENS AND THE NATURALIST. 69 
 
 suitable sizes. Take one of the rectangular pieces 
 and fold it from the bottom to within an inch of the 
 top ; turn down the top one incli, so that the upper 
 flap folds over the lower flap ; now turn the sides under 
 (or back) for a space of one inch, crease the edges 
 well and the pocket is complete. It will, of course, 
 be necessary to have assorted sizes of pockets, to suit 
 the sizes of the different specimens ; but do not make 
 too many different sizes, three will, perhaps, be enough 
 for all practical purposes. These pockets, with the 
 specimens, may be glued on the mounting sheets or in 
 the scrap-book ; in which case the label is pasted on 
 the outside of the lower flap. If the specimens are in- 
 tended for exchange the labels should be placed on the 
 inside with the specimen and not glued, so as not to 
 inconvenience the one with whom you are making ex- 
 changes, should he desire not to mount them with the 
 pockets. It must also be remembered that many crus- 
 tose soil-lichens and some of the smaller fruticose 
 forms can only be kept in pockets or boxes. There 
 are also other styles of pockets than the one here de- 
 scribed ; perhaps the reader will invent a better and 
 more convenient form. 
 
 Every specimen should be labelled ; in fact, a speci- 
 men without a label is of little value from a botanical 
 point of view. The label ghould be of sufficient size 
 for the following data : Name, where collected (give a 
 recognizable geographical locality), elevation, date 
 when collected, and the name of the collector. Labels 
 should either be printed, or written with pen and ink. 
 If labels are not at hand write the above items on the 
 
70 GUIDE TO THE STUDY OF LICHENS. 
 
 sheet or pocket ; even if the name of the specimen is 
 not known, do not fail to give the other data. 
 
 In conclusion, the following general advice may be 
 found useful. Put up only good large specimens ; 
 scrawny, small specimens are not desirable unless 
 they are the only kind obtainable in the locality. 
 Mount a goodly number of duplicate specimens for the 
 purpose of making exchanges. Make your exchanges 
 with a view to mutual gain ; to do this, it is necessary 
 to make exchanges with parties in widely different 
 localities ; state what you have and ask for what you 
 would like in exchange. 
 
 For mounting sheets, driers, labels, vasculums, in 
 fact anything desirable in a botanical line, enter into 
 communication with some dealer in botanical supplies. 
 Purchase only what is needed ; use home material as 
 much as possible. 
 
PART II 
 
 SYSTEMATIC STUDY OF LICHENS 
 
SYSTEMS OF CLASSIFICATION. 73 
 
 SECTION I. 
 
 SYSTEMS OF CLASSIFICATION. 
 
 In a general way it may be stated that one of the 
 ultimate aims of science is to classify. It must not be 
 supposed, however, that the mere naming and arrang- 
 ing of things is in itoelf the object in view. It is sim- 
 ply the means to an end ; classification simplifies the 
 work for those who follow : it, so to speak, represents 
 the status of the science under consideration. 
 
 One of the most common errors that amateur scien- 
 tists fall into is to suppose that a given system, we will 
 say of a group of plants, is something fixed and abso-^ 
 lutely reliable. This is by no meaiis the case; every 
 system, no matter how elaborate it may seem or by 
 whom it may be proposed, is imperfect and subject to 
 change as new discoveries are made. This, however, 
 does not imply that the existing systems are useless. 
 They are of inestimable value in so far as they repre- 
 sent the most reliable facts obtained in regard to the 
 science under consideration. As soon as a system fails 
 to be in harmony with the most advanced and reliable 
 investigations it will of necessity make way for a bet- 
 ter system. 
 
 Two kinds of systems are usually recognized : one is 
 known as the " artificial system," the other as the 
 " natural system." In the former no attempt is made 
 
74 GUIDE TO THE STUDY OF LICHENS. 
 
 to show the natural relationship of the organisms, 
 while in the latter an attempt is made to show the 
 affinities of families, genera and species. If, for in- 
 stance, all flowering plants are classified according to 
 the differences in the leaves, we have a purely artificial 
 system ; in such a system it would be necessary to 
 place together plants which have no close relationship ; 
 and, again, it would be necessary to separate others 
 which are undoubtedly closely related. In the so-called 
 natural system all the known characters are employed. 
 In the case, for example, of the flowering plants, not 
 only the leaf characters, but also those of the flowers, 
 the seed, the stem, the histological and physiological 
 differences, etc. 
 
 If we stop to consider, we find that the natural sys- 
 tem is, in a degree, also artificial, for the simple reason 
 that all of the facts regarding morphology and physiol- 
 ogy, evolution, etc, are not yet known, and, so far as 
 we know at present, never will all be known. Human 
 knowledge is finite ; it is, so to speak, hemmed in on 
 all sides ; what little we do recognize as "facts" has 
 for its basis something which is taken for granted, and 
 of which we therefore know nothing. 
 
 As regards the classification of lichens, it may be 
 stated that a natural system is practically non-existent. 
 Only within a few years have any efforts been made to 
 show the natural affinities of the different lichens and 
 lichen-groups. Heretofore, nearly every specialist on 
 lichenology had proposed a new system, thus adding to 
 the existing confusion. We now know that a lichen 
 is a morphological unit, which resulted from the sym- 
 
SYSTEMS OF CLASSIFICATION. 75 
 
 biotic association of a fungus and an alga. Lichens, 
 therefore, have a double affinity, being closely related 
 to the fungi on the one hand and to alga^ on the other. 
 Their true position is between the fungi and algae. 
 They are a class of the cryptogaraic (flowerless) plants 
 devoid of stem and leaves. We have already discussed 
 some of the structures of lichens which are analoirous to 
 certain structures of higher plants. This analogy does 
 not indicate any close natural relationship. Lichens 
 have no roots, leaves, branches, vascular tissue, epi- 
 dermis, etc., as we find them in higher plants ; the 
 analogies are indeed very remote. 
 
 The present tendency in classification is to proceed 
 from the lowest to the highest, from the less special- 
 ized to the more specialized, rather than from the 
 highest to the lowest. This is the natural way, as by 
 this method one can better explain the characters 
 which indicate their relationship. 
 
 Since lichens are treated as a distinct class and not 
 as fungi, the effort must be made to show their rela- 
 tionship to each other ; in order to do this, we must 
 also study their relationship to the fungi by endeavoring 
 to find their probable fungal ancestors. Such attempts 
 have recently been made by Reinke and others, but 
 much remains yet to be done. 
 
 The amateur need not worry about the imperfections 
 indicated ; the systems at hand will suffice for the 
 present ; future generations will work with other sys- 
 tems. 
 
76 GUIDE TO THE STUDY OF LICHENS. 
 
 SECTION 11. 
 KEYS TO THE STUDY OF LICHENS. 
 
 Keys to a system of plants are of value, but this 
 value is generally overestimated The usefulness of a 
 key depends largely upon the one who makes it ; if 
 he has a thorough knowledge of the subject, he is 
 generally able to construct a key which will be found 
 highly useful by others. Any key, whether natural or 
 artificial, should contain the fewest words possible 
 consistent with clearness ; close attention must also be 
 given to co-ordination and subordination. 
 
 Two keys are here proposed : one, the artificial, in- 
 tended for those who cannot secure the use of a com- 
 pound microscope, and who are dependent upon the 
 eye and a pocket-lens to aid them ; the second, a nat- 
 ural key, recommended to those who have a compound 
 microscope at their disposal. 
 
 It will be noticed that in the artificial key the thal- 
 lus and apothecia are of prime importance ; in the 
 natural key the algae and spores are of first importance 
 in the determination of genera. No attempt has been 
 made to arrange keys to the species. 
 
 In the artificial key it was found necessary to com- 
 bine several genera in some instances, because no marked 
 macroscopic differential characters were noticeable. 
 Furthermore, several insignificant genera have been 
 wholly omitted. 
 
KEYS TO THE STUDY OF LICHENS. 77 
 
 I. ARTIFICAL KEY TO THE MORE IMPORTANT GENERA 
 OF LICHENS OCCURRING IN THE UNITED STATES. 
 
 Thallus Crcstose. 
 
 Stipes present with terminal apothecia, plants small. 
 Stipes and apothecia black. 
 Apothecia somewhat flattened (discoid) . . Cyphelium. 
 
 Apothecia globose (spherical) Calicium. 
 
 Stipes light colored. 
 Apothecia small, brownish, bark-lichens . . Coniocybe. 
 Apothecia large, earth-lichens Bceomyces. 
 
 Stipes wanting, apothecia more or less immersed. 
 Apothecia distinctly linear. 
 
 Length of apothecia usually exceeding four times their 
 
 width ; black or white Graphis. 
 
 Length of apothecia usually not exceeding four times 
 their width ; black. 
 
 On decaying wood Xi/lographa. 
 
 On bark of trees Opegrapha. 
 
 Apothecia not linear, irregular. 
 
 Oval or oblong Hazslinskya. 
 
 Irregular, not oval or oblong. 
 Disk distinctly visible, black. 
 
 Apothecia small Arthonia. 
 
 Apothecia comparatively large . . . Arthothelium 
 Disk indistinct, mostly immersed . . . Mycoporum. 
 
 Apothecia regular in outline. 
 Immersed in thallus or substratum ; globose. 
 Not in colonies. 
 
 Disk light colored Pertusaria. 
 
 Disk black or dark. 
 
 Occurring on rocks Verrucaria. 
 
 Occurring on bark 
 Apothecia almost entirely covered 
 
 by substratum Pyrenula. 
 
 Apothecia more elevated, urn- 
 shaped Gyrostomum. 
 
 Apothecia crateriform Thelolrema. 
 
 In colonies Trypethelium. 
 
 Immersed in thallus ; not globose. 
 
 Disk not projecting above surface of tliallus. 
 
 Thallus light-gray Urreolaria. 
 
 Thallus dark Acarospora. 
 
 Disk projecting above the green thallus . . Acolium. 
 
78 GUIDE TO THE STUDY OF LICHENS. 
 
 Hypothecium black ^ -J 
 
 Apothecia discoid or semiglobose ; sessile, not immersed. 
 Disk black or dark. 
 
 Bacidia. 
 Lecidea. 
 
 i Biatora. 
 
 Hypothecium colorless ) Bilimhia. 
 
 ( Lecanora. 
 
 Disk orange to rusty-red Placodium. 
 
 Thallus Foliose. 
 
 Thallus entire or lobes plicate, grayish-brown or dark. 
 Apothecia innate or immersed. 
 Apothecia comparatively large ; innate in depressions 
 
 of the thallus Heppia. 
 
 Apothecia small, immersed. 
 Thallus simple, very minute, adnate, . Dermatocarpon. 
 Thallus about five mm. in diameter, not 
 
 closely adnate Psora. 
 
 Thallus large, umbilicate Endocarpon. 
 
 Apothecia sessile, black ; thallus large, umbilicate, 
 
 Thallus pustular Umbilicaria. 
 
 Thallus not pustular Gyrophora. 
 
 Thallus distinctly lobed or branching, usually large. 
 Apothecia cup-shaped or discoid, sessile. 
 Cyphellae present.2 
 Thallus blue-green to dark-brown, soredia 
 
 yellow Stictina. 
 
 Thallus greenish to light-brown, soredia 
 
 not yellow Sticta. 
 
 Cyphallae wanting. 
 Thallus ash-gray, comparatively small. 
 Branching distinct, lobes of uniform 
 
 width Speerschneidera. 
 
 Branching less distinct, lobes not of 
 
 uniform width Physcia. 
 
 Branching indistinct, thallus thin, 
 
 closely adnate Pyxine. 
 
 Thallus greenish, more rarely brown to 
 
 dark, large Parmelia. 
 
 Thallus brown, small, closely adnate . . . Pannaria. 
 
 * Make a vertical section through the apothecium and examine 
 with a good pocket lens. 
 
 * Sticta amplissima and S. pidmonaria are devoid of cyphellae. 
 
KEYS TO THE STUDY OF LICHENS. 79 
 
 Tliallus distinctly blue-green to dark-blue, 
 thin, higlily gelatinous when moist. 
 
 Lower surface devoid of long rhizoids, | CoUema. 
 Lower surface bearing long rhizoids, 
 
 thallus comparatively thick .... Mallotium. 
 
 Lower surface veined Hydrothyria. 
 
 Apothecia innate, not cup-shaped. 
 
 On lower surface of upturned lobes . . . Nephromium. 
 On upper surface of thallus. 
 Thallus comparatively small, apothecia 
 
 not marginal Solorina. 
 
 Thallus large, apothecia marginal .... Peltigera. 
 
 Thallus Fruticose. 
 
 Thallus very minute, dark-blue, scarcely visible to the 
 naked eye. 
 Apothecia terminal, more or less globose. 
 
 Thallus-lobes distinctly flattened .... Omphalaria. 
 Thallus-lobcs not distinctly flattened .... Lichina. 
 
 Apothecia lateral, discoid Poiychidium. 
 
 Apothecia within thallus Ephebe. 
 
 Thallus distinct to very large. 
 
 Yellowish coloration in thallus or apothecia. 
 
 Thallus distinctly flattened Theloschistes. 
 
 Thallus not distinctly flattened Evernia. 
 
 Yellowish coloration wanting. 
 
 Thallus flattened, thick, not brown or dark. 
 
 Disk black, thallus gray to purplish . . . Rocella. 
 
 Disk not black, thallus greenish Ramalina. 
 
 Thallus flattened, thin, brown to dark . . . Cetraria. 
 Thallus cylindrical, hollow. 
 Apothecia terminal. 
 
 Disk black PiJophoron. 
 
 Disk brown or red Chdonia. 
 
 Thallus cylindrical, solid. 
 Branches long, pendulous. 
 
 Color green to grayish-green Usnea. 
 
 C Bryopoqon. 
 Color dark to black < Alector'ia. 
 
 Branches rigid, erect. 
 
 Smooth, shiny Sphcerophoi-us. 
 
 Not smooth, warty Stereocaulon. 
 
80 GUIDE TO THE STUDY OF LICHENS. 
 
 II. NATURAL KEY TO THE FAMILIES. 
 
 The natural keys to the genera are given after the 
 description of the families. In the use of the natural 
 key to the families and genera, the beginner is depend- 
 ent upon the use of the compound microscope. The 
 student is advised to keep in mind the suggestions 
 given in the chapter on " The Study of Lichens." 
 
 KEY. 
 
 Algae of the thallus bright-green. 
 Fungal type of apothecium. 
 
 Apothecia terminal on stipes or on the f ruticose thallus. 
 Disk closed, finally opening by a terminal pore or 
 crevice /. CALJCIACEjE. 
 
 Disk open, convex, light-brown or red, 
 
 //, CLADONIACEjE. 
 
 Apothecia sessile on the crustose or foliose thallus. 
 Disk cup-shaped, flattened or convex, brown or black, 
 
 ///. LECIDEACE^. 
 
 Apothecia linear, irregular or stellate ; thallus crus- 
 tose IV. GRAPHIDACE^, 
 
 Thalline type of apothecium or apothecia immersed in 
 the thallus. 
 Apothecia discoid and sessile, rarely immersed. 
 
 Plasmic masses of spores united, spores two-celled, 
 
 r. PHTSCIACEuE. 
 
 Plasmic masses of spores not united, 
 
 VI. PARMELIACE^. 
 
 Apothecia immersed in the substratum or thallus, 
 
 opening by a minute pore, VII. VERRUCARIACEM. 
 Algae of the thallus blue-green.^ 
 
 Thallus foliose, dark-blue, gelatinous when moist, 
 
 VIII. COLLEMACEJS. 
 
 Thallus minutely fruticose or foliose, not gelatinous when 
 
 moist IX. PANNARIACEjE. 
 
 The descriptions of the families and genera will be 
 made as brief as possible. Those who wish to study 
 
 1 The following genera of the Pannariaceae ha.ve bright-green algse; 
 Nephroma, Solorina, Sticta and Psoroma, 
 
GENERA ANt) SPECIES. 81 
 
 the affinities of the various groups are referred to more 
 complete works on the subject. It is intended to devote 
 most attention to the description of the species, dwell- 
 ing particularly ui)on the points of liistorical interest, 
 thus rendering the subject less dry and monotonous. 
 
 An attempt has been made to arrange the genera and 
 species in a natural order beginning with the lowest. 
 
 /. CALICIACE^. 
 
 With comparatively few exceptions, the representa- 
 tives of this family are insignificant in appearance. 
 The thallus is either crustose or fruticose. The 
 apothecia are globose and terminal upon the stipes 
 or on the branches of the fruticose thallus. A stipe is 
 a small, simple, erect stalk devoid of algae, hence is not 
 a part of the thallus ; it is an apothecial stalk bearing 
 the apothecia. 
 
 Upon an examination of the Caliciaceae, it will be 
 found that the spore-sacs dissolve and set free the im- 
 mature spores which lie above the thecium and are 
 covered over by the exciple (proper exciple). Finally, 
 there is a rupture of the apical portion of the apothe- 
 cium, setting free the spores. 
 
 None of the representatives of this family have any 
 special historical interest. 
 
 KEY TO THE GENERA. 
 
 Thallus crustose. 
 Apothecia terminal on slender stipes. 
 
 Spores simple, colorless 1. Coniocyhe. 
 
 Spores two-celled, dark 2. Calicium. 
 
 Spores simple, dark 3. Ci/p/ielium. 
 
 Apothecia sessile ; spores two-celled, dark, 4- Acolium. 
 Tliailus rigidly fruticose, terniiual apothecia, 5. Splui^rophorus. 
 
82 GUIDE TO THE STUDY OF LICHENS. 
 
 1. Coniocyhe} 
 
 The representatives of this genus are few and insig- 
 nificant; close examination is necessary to detect 
 them. Usually, they occur upon the bark of trees in 
 shaded places ; less commonly upon decaying wood. 
 The thallus is generally visible to the naked eye, and 
 has a yellowish tinge. The apothecia and stipes are 
 of a light color, never black ; however, the color is 
 quite variable, ranging from almost white to brownish- 
 gray and reddish-brown. The alg^e seem to belong to 
 the genus Chroolepus and, therefore, occur in chains. 
 The spores are spherical, small, simple, colorless, or 
 faintly yellowish, with a distinct, irregular exosporium, 
 which is readily removed, T/x to 8/x.^ 
 
 Coniocyhe pallida is the only species which is likely 
 to be found. Coniocyhe furfur acea is usually sterile, 
 that is, devoid of stipes and apothecia. 
 
 1. Coniocyhe pallida. Thallus usually indistinct, 
 whitish. Stipes comparatively long and slender, from 
 nearly white to brown, bearing single globose apo- 
 thecia of nearly the same color as the stipe. Spores 
 simple, colorless, exosporium quite distinct, 1 fx. to 8/x. 
 On bark. New England (New Hampshire), Iowa. 
 
 2. Coniocyhe furfuracea. Thallus quite distinct, of 
 a sulphur color. Stipes, apothecia and spores as in 
 C. pallida. On the exposed roots of trees and decay- 
 ing wood. New England, New York. Sterile in Iowa. 
 
 1 The spores of all the genera mentioned are figured on Plates V to 
 XI inclusive. The genera are given alphabetically. 
 
 2 A /(i or micron equals a thousandth of one millimeter or one 
 twenty-five-thousandth of an inch. The measurements are made 
 with the aid of an eye-piece micrometer. 
 
GENERA AND SPECIES. 83 
 
 2. Calicium. 
 This genus is represented by a considerable number 
 of species, which are uniformly insignificant plants, 
 having no special interest for the amateur. In form 
 they resemble Coniocybe. The stipes and apothecia 
 are black, in other respects like those of Coniocybe, 
 They occur upon tree trunks in shaded places, upon 
 fences and decaying wood. The algae are Protococus 
 viridis ; they occur singly, and are of a bright-green 
 color. In some species the thallus is very deficient, 
 or even wholly wanting, particularly in older speci- 
 mens. Some species are included among fungi 
 (Mucor) by various authors. 
 
 Tiie spores are two-celled and dark. 
 
 1. Calicium Curtisii. Tliallus wanting, or very 
 rudimentary. Stipes dark, slender, bearing a single, 
 dark, globose apothecium. Spores brown, two-celled, 
 oblong, with pointed ends, 14/x X 5/x. 
 
 Occurs on tree-trunks, especially species of Hhus. 
 
 2. Calicium fuscipes. Thallus rarely recognizable. 
 Stipes rather long and slender, dark-brown. Apo- 
 thecia spherical, dark-brown ; in fully matured plants 
 the entire thecium may fall away. Spores dark-brown, 
 elliptical, simple, 12/x X 5.5/x. 
 
 3. Calicium lenticulare. Thallus indistinct, color- 
 less or whitish. Stipes rather short and thick. Apo- 
 thecia comparatively large and somewhat flattened. 
 Spores small, dark-brown, elliptical, simple, 6.0/x X 4^. 
 
 4. Calicium hyperellum. Thallus only slightly de- 
 veloped, greenish-yellow, unevenly spreading. Stipes 
 long, slender, dark-brown. Apothecia usually spheri- 
 
84 GUIDE TO THE STUDY OP LICHENS. 
 
 cal, dark-brown or rusty-brown. Spores brown, ellip- 
 tical, two-celled, somewhat constricted in the middle, 
 10/x X 6/x. 
 
 5. Calicium quercinum. Thallus much as in C. 
 hyperellum, less highly developed, not greenish-yellow. 
 Stipe less slender, dark-brown. Apothecia usually 
 spherical, dark-brown. The entire structure, includ- 
 ing spores, resembling that of C. hyperellum. Spores 
 brown, two-celled, constricted in the middle, 10/x X ^yu,. 
 
 3. Gyphelium. 
 
 The representatives of this genus have the general 
 characters of the Calicii. The apothecia are some- 
 what flattened and the spores are simple and dark, 
 thus contrasting them with those of Coniocyhe and 
 Calicium, the exosporium is generally considerably 
 thickened. In form they are usually spherical though 
 they may be elliptical. The alg^e are as in Calicium. 
 In fact the amateur will perhaps place the speci- 
 mens with the Calicii owing to their great similarity. 
 They occur in the same localities as the other Cali- 
 ciaceae. 
 
 1. Cyphelium turhinatum. Thallus crustose, well 
 developed. Stipe very short, projecting slightly 
 above the lobes of the thallus. Apothecium much 
 as in the foregoing, dark-brown, entirely closed at 
 first, later opening by Cep-segment. Spores small, 
 dark brown, spherical, simple, exine considerably 
 thickened, 7.5/x, X 6.5/a. 
 
 2. Cyphelium tuhoBforme. Thallus occurs almost 
 entirely under the bark, fairly developed. Stipe 
 
GENERA AND SPECIES. 85 
 
 rather short, of medium thickness, dark. Apothecia 
 somewhat flattened, dark. Spores rather large, sim- 
 ple, dark-brown; usually spherical; some slightly 
 elongated with pointed tips, exine distinct, 12/x X 20/a. 
 
 Jf.. Acolium. 
 This genus is undoubtedly closely related to Calu 
 cium. The thallus is well developed and of a marked 
 green color in A. tigillare. The stipe is much re- 
 duced, so that the apothecium is sessile or immersed 
 in the thallus. The thallus encloses the apothecium 
 in a crater-like fashion, showing the dark epithecium 
 at the top. The spores are two-celled and dark. 
 The algas are as in CaUcium. 
 
 There are only two species reported in the United 
 States, of which A. tigillare is quite common. Its 
 natural substratum seems to be old pine fence-boards, 
 upon which it occurs in patches of considerable extent. 
 From its position it is evident that it has the ability 
 to resist greater extremes of dryness than the major- 
 ity of lichens. It occurs quite frequently on fence- 
 boards in prairie farm-yards which are comparatively 
 little shaded. 
 
 1. Acolium tigillare. Thallus distinctly crustose 
 and minutely areolate, yellowish-green. Apothecia 
 numerous; the very short stipes, as well as the 
 greater portion of the apothecium, are enclosed by 
 the thallus, producing conical elevations. Epithecium 
 dark. Spores two-celled, somewhat constricted at the 
 middle, thick, dark spore-wall, 10/x X 14/x. 
 
86 OmDE TO THE STUDY OF LICHENS. 
 
 5. Sphcerophorus. 
 
 This genus represents the highest development .of 
 the Caliciaceae, there is a wide gap between it and 
 Acolium. The links are entirely wanting in the 
 United States. It has been questioned whether 
 Sphaerophorus belongs to the Caliciaceae ; concerning 
 this there can, however, be no doubt. The apothecia 
 and spore characters are the same as those of the other 
 genera. 
 
 The thallus is fruticose, quite large, of a rigid car- 
 tilaginous consistency ; color brown or reddish-brown. 
 The apothecia are globose and terminal on the branches 
 of the thallus ; they open by terminal chinks, thus set- 
 ting free the simple dark spores. The spores are char- 
 acterized by the irregular dark blue exine (exosporium) 
 which is readily removed. 
 
 1. Sphcerophorus fragilis. Thallus-lobes cylin- 
 drical, smooth, color somewhat variable, from light 
 gray, brownish to dark, dichotomously branching, ends 
 of branches usually with numerous short lobes, tips 
 blunt or rounded. Usually sterile or apothecia few, 
 shrunken. Disk black. Entire apothecium easily re- 
 moved at the hypothecial zone. Spores elliptical, 
 simple, dark-brown exine, 15/x X 10/>i- 
 
 2. Sphcerophorus glohiferous. Thallus lobes cylin- 
 drical, variable in length, usually of uniform brown 
 color, especially in old herbarium material. Branch- 
 ing dichotomous. Apothecia globoid, opening by 
 chinks or pores. Spores spherical, simple, blue-black 
 exine easily removed by pressure, 12/x X IV* 
 
GENERA AND SPECIES. 87 
 
 77. CLADONIACE^. 
 
 The representatives of this family are quite common 
 everywhere, occurring chiefly upon soil or rocky 
 ledges ; less commonly upon old fences, tree-trunks and 
 rotten wood. They are conspicuous as to size. The 
 thallus is peculiar in that it is made up of two parts: 
 one erect (secondary thallus or podetium, hence fruti- 
 cose), varies from simple to much branched ; the other 
 portion (primary thallus), spreading over the substra- 
 tum, varies from crustose {Bceomyces) to foliose {Cla- 
 donid). Strictly speaking, the upright portion of 
 Bceomyces is only a stipe, as in the preceding family. 
 
 The apothecia are distinct and occur in all the 
 genera excepting ThamnoUa, which is always sterile. 
 They are more or less globose, disk convex to flat- 
 tened but never cup-shaped. No alg£e occur in any 
 part of the apothecia ; for that reason they belong to 
 the fungal type. (See Figs. 1 and 2, Plate IV.) 
 
 KEY TO THE GENERA. 
 
 Thallus (primary) crustose or warty. 
 Apothecia borne on unbranched thick stipes or nearly 
 
 sessile 1. Bceomyces. 
 
 Apothecia terminal on the erect tliallus (podetia). 
 
 Erect thallus hollow, spores simple . . 2. Pilophoron. 
 Erect thallus solid, spores four-celled . 3. Stereonndon. 
 Thallus (primary) foliose or wantinfj, erect thallus hollow. 
 Apothecia usually present, disk brown or red, 
 
 4- Cladonia. 
 Apothecia always wanting, erect thallus tapering, 
 
 5. Thamnolia. 
 1. Bceomyces. 
 
 The representatives of this genus usually occur 
 upon loamy or sandy soil in forest lands. Tlie primary 
 thallus is usually crustose ; in some of the Southern 
 
88 GUIDE TO THE STUDY OF LICHENS. 
 
 forms it, however, becomes almost foliose. The name 
 Bceomyces meaus a " small fungus," or " toadstool." 
 The light color of the stipes and apothecia do give it a 
 marked resemblance to the fungi of the mushroom or 
 toadstool order. The stipes are never branching, and 
 are almost entirely wanting in one species. The apo- 
 thecia are well developed and vary from globose to dis- 
 tinctly flattened. The algae are light-green, single- 
 celled, belonging to Protococcus. A Glceocapsa also 
 occurs with some species (^B. roseus). Spores are col- 
 orless, spindle-shaped to almost acicular, simple or 
 very indistinctly septate. 
 
 None of the species have been credited with any 
 special virtues. 
 
 The collector will meet with these plants in forest 
 lands, where they occur in patches, usually several feet 
 (sometimes less) in diameter. B. roseus is most com- 
 mon, and is characterized by a greenish-gray crustose 
 thallus, which is in marked contrast with the soil. 
 Care is necessary to preserve the specimen. Place the 
 lichens, attached to a considerable portion of the soil, 
 in a suitable pasteboard box, or wrap carefully in pa- 
 per. They had best be kept in paper pockets or in 
 small pasteboard boxes, as indicated. 
 
 1. Bceomyces roseus. Thallus granulose, greenish. 
 Stipes comparatively long, white or a faint rosy tint. 
 Apothecia, spherical (both stipe and apothecium col- 
 lapse on drying). Disk a rosy tint. Spores in long 
 slender sacs, acicular, usually slightly curved, some- 
 times faintly septate, colorless, 25.5/a X 3.5/i. 
 
GENERA AND SPECIES. 89 
 
 2. BcBomyces ceruginosus. Thallus evenly spread- 
 ing, with rather large granules, gray-green. Stipes 
 very short or none. Apothecia quite flat, yellowish 
 disk. Spore-sacs long, cylindrical ; spores oblong, col- 
 orless, usually distinctly uniseptate, 17/x X 8/m, rather 
 variable in size and form. 
 
 S. Bceomyces byssoides. Thallus granulose, with ele- 
 vated, flattened squamules. Stipes longer than in 
 ceruginosus, flattened above. Apothecia flattened. 
 Disk reddish-brown. Spores simple, colorless, ellip- 
 tical, 10/x X -i/A. 
 
 2. Pilophoron. 
 
 This genus is represented by one well-marked spe- 
 cies, which is" of rare occurrence. It seems to be some- 
 what northern in its range, preferring moist, shaded 
 places. 
 
 The primary thallus is deficient, warty, greenish- 
 gray. The vertical thallus (secondary thallus, or pode- 
 tium) consists of an erect stem, which may be once, or 
 very rarely twice, branched toward the top. Upon 
 examining a transverse section it is found that this 
 stem is hollow (lumen is narrow, however), and that 
 it contains algjfe (Protococcus), thus being essentially 
 different from the stipe of Bceomyces. 
 
 The apothecia are terminal, globose, black or blue- 
 black. The spores are simple, oblong to spindle- 
 shaped, colorless. 
 
 1. Pilophoron cereolus. Primary thallus granular, 
 greenish to gray ; podetia, from medium to long and 
 slender, simple, or once or twice branched above, gran- 
 ular, greenish to gray. Apothecia comparatively large 
 
90 GUIDE TO THE STUDY OF LICHENS. 
 
 and numerous, nearly spherical. Thecium of a blue- 
 black tint near the top. Disk blue-black, smooth. 
 Spores simple, elongated, colorless, 25.5^ X 7/x. 
 
 3. Stereocaulon, 
 
 The most marked morphological character of this 
 genus is the comparatively large fruticose thallus ; it 
 consists of numerous crooked and somewhat flattened 
 branches, which are covered by warty thalloid out- 
 growths. Upon careful examination numerous dark- 
 blue cephalodia will be found on different parts of the 
 branches. The color of the thallus is generally ash- 
 gray. 
 
 The primary thallus is deficient, so much so that the 
 average collector will take no notice of it whatever. 
 The secondary thallus is not hollow, as in the foregoing 
 genus When dry, the Stereocaulons are very brittle. 
 They occur most commonly upon rocky ledges in hilly 
 and mountainous regions. They are somewhat north- 
 ern in their range. 
 
 The apothecia are terminal, medium size, globose or 
 flattened, dark-brown to nearly black. The spores are 
 colorless, spindle-shaped, usually four-celled. The fol- 
 lowing are the more common species : 
 
 1. Stereocaulon condensatum. Primary thallus dis- 
 tinct, granular and warty, green to dark-gray. Pode- 
 tia short, branched, covered with thalloid warts re- 
 sembling those of the primary thallus. Apothecia 
 rather large, simple or confluent. Disk convex, dark- 
 brown. Spores acicular, triseptate, colorless, 25/a 
 X 2.5/x. 
 
GENERA AND SPECIES. 91 
 
 2. Stereocaulon coralloides. Primary tliallus coarsely 
 granular or warty in young plants, grayisli-wliite, usu- 
 ally wanting in fully developed plants. Podetia rather 
 long and slender, more or less compressed, much 
 branched, profusely covered with coarsely granular or 
 warty outgrowths, light-gray to rather dark (cephalo- 
 dia common). Apothecia medium, nearly spherical, 
 often wanting. Disk brown to black. Spores color- 
 less, triseptate, elongated, ends pointed, 27/x X 6/x. 
 
 3. Stereocaulon denudatum. Primary thallus gran- 
 ular and irregularly globular, usually wanting. Pode- 
 tia much as in S. coralloides^ thalloid warts more or 
 less confluent, sometimes flattened, greenish to gray ; 
 lower, hence older, portions of branches quite bare 
 (free from thalloid warts), and of a brownish color. 
 Apothecia and spores as in S. coralloides. 
 
 Jf. Stereocaulon ramidosum. Primary thallus of 
 flattened squamules, with crenate margins usually want- 
 ing. Podetia usually long, otherwise, as in S, coral- 
 loides^ covered with flattened thalloid warts, with cre- 
 nate margins. Apothecia from small to large, simple, 
 confluent to flattened. Disk, dark-brown or black. 
 Spores as in S. coralloides. 
 
 5. Stereocaulon paschode. Primary thallus granular, 
 usually wanting. Podetia long, much branched, cov- 
 ered with minutely branching outgrowths. Apothecia 
 and spores as in S. coralloides. 
 
 Species 2, 3, 4 and 5 are in many respects closely 
 similar ; so much so that it seems probable that they 
 are mere variations of one species. Further oaroful olv 
 servation and study are necessary to prove whether or 
 
92 GUIDE TO THE. STUDY OF LICHENS. 
 
 not this be true. *S'. paschale is a typical rock-lichen. 
 It is said to be the first plant to develop upon the 
 volcanic lava of Vesuvius and Ischia. In various parts 
 of Europe wild animals feed upon it. In Lapland the 
 reindeer often feed upon it when Gladonia rangiferina 
 is scarce. 
 
 Jf.. Cladonia. 
 
 This genus is represented by a great number of 
 species which are so variable and diversified in form 
 that the systematist has considerable difficulty in de- 
 fining their limitations and describing them clearly. 
 It is, however, fortunate that nearly all of the repre- 
 sentatives are readily recognized as belonging to 
 Cladonia. A few species are also quite characteris- 
 tic as to form and once seen are not likely to be for- 
 gotten or mistaken for any other species ; such are (7. 
 rangiferina, G. papillaria, C. pyxidata, G. cariosa, 
 and a few others. 
 
 Excepting in G. papillaria, the primary thallus is 
 foliose, although the individual thalli are minute ; 
 sometimes simple and entire, again considerably lobed 
 or even distinctly branching. Usually a large num- 
 ber of thalli occur together, more or less imbricate 
 with one side elevated. The upper surface is dis- 
 tinctly bright-green, the iower surface whitish. The 
 vertical thallus (secondary thallus, podetium) is 
 very variable in form ; from simple to much 
 branched. The simple forms, again, vary as to size 
 and structure ; some are nearly smooth, while others 
 bear numerous leafy outgrowths resembling the pri- 
 mary thalli ; some are cup-like toward the apex. 
 
GENERA AND SPECIES. 93 
 
 while others have several of these cup-like or dis- 
 coid expansions at regular intervals. The branching 
 forms also vary greatly as to size, manner of branch- 
 ing, etc. The color varies somewhat ; greenish-gray, 
 however, prevails. The podetia are hollow, and ex- 
 emplify a mechanical type especially adapted to re- 
 sist lateral forces (air currents). 
 
 The apothecia are terminal upon the podetial 
 branches, or short apothecial stalks borne upon the 
 margin of the cup-shaped or cfiscoid expansions. 
 They are usually simple or more or less confluent, 
 globose, either brown or bright-scarlet. The scarlet 
 apothecia at once prove the specimen a species of 
 Cladonia. The spores are simple, elliptical, color- 
 less, and vary little in the different species. It must 
 also be remembered that some of the higher Cladonias 
 are constantly sterile. 
 
 The Cladonias are widely distributed ; they occur 
 upon soil and rock, less commonly upon tree-trunks 
 and fences. They are northern in their range. 
 
 1. Cladonia papillaria. Primary thallus crustose 
 to warty. Podetia (secondary thalli) short, smooth, 
 club-shaped, somewhat tapering near the apex. 
 Apothecia rare in some localities, small, more or less 
 confluent. Disk convex, brown. Spores simple, ellipti- 
 cal, colorless.* 
 
 ^ This species is quite common on soil in the hilly 
 districts of New Jersey and eastern Pennsylvania. 
 
 » The spores of the Cladonias are so closely siiuilHr that the 
 measurements ami special descriptions will be oniiited in most 
 instances. The average measurements are 14 microns in length by 4 
 miorons in width. ' 
 
94' GUIDE TO THE STUDY OF LICHENS. 
 
 Formerly it was classified with another genus {Pyc- 
 nofhelia), which is not at all surprising because it cer- 
 tainly has few characters in common with most (7/a- 
 donias. 
 
 2. Gladonia delicata. Primary thallus consists of 
 numerous medium sized, closely crowded lobes, 
 which are sometimes finely branched. Podetia short, 
 slender, sometimes branching above. Apothecia 
 medium, confluent. Disk convex, brown. Spores 
 rather small. 
 
 3. Gladonia ccespiticia. Primary thallus well 
 developed, much cleft or irregularly branching. 
 Podetia very short or wanting. Apothecia medium. 
 Disk convex, brown. Spores comparatively numer- 
 ous and a little above the average in size. 
 
 J/., Gladonia symphycarpa. Primary thalli well 
 developed, usually rounded, sometimes elongated, 
 branching inconspicuous, upper surface generally 
 convex. Podetia short, rather thick, slightly 
 branching. Apothecia well developed. Disk con- 
 vex, confluent, dark-brown. Spores rather large, 
 15/x X 3.5/A. 
 
 5, Gladonia mitrula. Primary thalli usually 
 small, numerous, rounded, almost entire, sometimes 
 much enlarged and branching. Podetia from short 
 to medium, entire or rarely branching near the 
 apex. Apothecia medium to large, usually conflu- 
 ent. Disk convex, brown. Spores numerous. 
 
 6. Gladonia pulchella. Primary thallus well de- 
 veloped ; lobes branched, elongated, slender. Podetia 
 somewhat elongated, branched toward the apex, bear- 
 
GENERA AND 8PKCIE8. 95 
 
 ing thalloid outgrowths. Apothecia rather large, usu- 
 ally coufluent. Disk convex, scarlet. Spores normal 
 in size and form. 
 
 7. Gladonia cariosa. Primary thallus usually well 
 developed ; lobes from small and simple to large and 
 irregularly branching, with crenate margin. Podetia 
 of medium length, expanded and irregularly branch- 
 ing above, warty. Apothecia numerous, rather large. 
 Disk convex, brown. Spores colorless, elliptical, sim- 
 ple, Utx X 3.5/x. 
 
 8. Gladonia decorticata. Primary- thallus fairly 
 well developed ; lobes usually small and almost entire, 
 sometimes large and much branched, margin crenate. 
 Podetia medium to long, branched above, finely gran- 
 ular and sometimes bearing thalloid outgrowths, but 
 soon becoming decorticate, beginning at the base. Apo- 
 thecia very numerous, medium size, confluent. Disk 
 convex, brown. Spores rare. 
 
 9. Gladonia macilenta. Lobes of primary thallus 
 scattered over substratum, variable in size and branch- 
 ing ; margins distinctly crenate. Podetia medium, slen- 
 der to rather thick, covered by scaly thalli which dis- 
 
 *appear after a time. Apothecia medium to large, con- 
 fluent. Disk convex, scarlet. Spores normal. 
 
 10. Gladonia cristatella. Primary thallus fairly well 
 developed; lobes from small and almost entire to large 
 and branching, usually more or less adnate. Podetia 
 medium, branched above, rarely simple, gniiiular, bear- 
 ing secondary thalli. Apothecia very numerous, me- 
 dium size, confluent. Disk convex, scarlet. Spores 
 rare. 
 
96 GUIDE TO THE STUDY OF LICHENS. 
 
 11. Gladonia cenotea. Primary thallus usually 
 absent ; when present, large, elongated and much 
 branched. Podetia rather long and thick, branched 
 near the top, lower portion often bearing thalloid lob- 
 ules. Apothecia rare. Disk flesh-colored to dark- 
 brown. Spores usually wanting. 
 
 12. Gladonia alcicornis. Primary thallus well de- 
 veloped, much elongated, branched, margin crenate. 
 Podetia not very numerous, often wanting, medium 
 height and thickness, much expanded above, either cup- 
 shaped or leaf-like, bearing a few usually large thalloid 
 lobules. Apothecia sessile or on short stalks, rather 
 small. Disk convex, light-brown to reddish-brown. 
 
 13. Gladonia lepidota. Primary thallus of much 
 elongated and divided lobes. Podetia medium, spar- 
 ingly branched toward the base ; much branched near 
 the apex, bearing many thalloid lobules. Apothecia 
 often wanting. 
 
 1^. Gladonia pyxidata. Primary thallus well de- 
 veloped; lobes rather large, broad, and indistinctly 
 branched. Podetia from short to medium in length, 
 from medium to very thick, much expanded above, not 
 branching, scaly, sometimes bearing a few thalloid 
 lobules. Apothecia rare, on short stalks, small. Disk 
 convex, somewhat confluent, brown. 
 
 Lindsay says of this lichen, " It is the ' cup-moss ' of 
 the London herbalists. It contains a considerable 
 quantity of gummy or starchy matter, and has been 
 much used as a demulcent in various chest affections." 
 Its medicinal uses, which have been most varied, have 
 resembled those of Getraria Islandica, 
 
GENERA AND SPECIES. 97 
 
 15. Cladonia deformis. Primary thallus sparingly 
 present or wanting. Podetia from medium to long, 
 very rarely bearing thalloid lobules, rather thick, ter- 
 minating in a cup which becomes degenerate and indis- 
 tinct with age. Apothecia on secondary branches of 
 considerable length, which grow from the margin of 
 the cup ; rather large, confluent. Disk convex, scarlet. 
 
 16. Cladonia hellidi flora. Primary thallus fairly 
 well developed. Lobes rather large, irregularly branch- 
 ing. Podetia long, thick to very thick, rarely branch- 
 ing, usually covered with thalloid lobules. Apothe- 
 cia large, irregular in outline. Disk a bright-scarlet. 
 Spores 13.5/i, X 3.5yot. 
 
 n. Cladonia cornucopioides. Primary thallus- 
 lobes irregularly scattering, rather long, branching. 
 Podetia of medium length, rather thick, expanded, 
 trumpet-shaped above, covered by minute scaly warts. 
 Apothecia on short stalks growing from the edge of 
 the expanded portion ; entire, orbicular to elongated, 
 variable in size and form. Disk bright-scarlet. 
 Spores 10/a X 2.5/x. 
 
 " This is probably the ' red cup-moss ' of which Mrs. 
 Hemans sings in the following stanza : 
 
 " ' Oh ! green is the turf where my brothers play 
 Through the long bright hours of the summer day ; 
 They find the red cup-moss where they climb. 
 And they chase the bee o'er the scented thyme.' 
 
 " It occurs in the antarctic regions and is otherwise 
 somewhat widely distributed. It appears to contain a 
 small quantity of gummy and starchy matter ; hence 
 
98 GUIDE TO THE STUDY OF LICHENS. 
 
 it lias been used, boiled in milk or syrup, in whooping- 
 coush and other chest affections in children. In Thu- 
 ringia, a decoction has been used in the treatment of 
 intermittent fevers." — Lindsay, 
 
 18. Cladonia digitata. Primary thallus large, rarely 
 branching, minutely lobed with crenate margin. Pode- 
 tia medium in length, from slender to thick, expanded 
 into an irregular cup with incurved margin ; secondary 
 branches show a palmate, one-sided development from 
 the margin of the cup, that is, some of the secondary 
 branches remain rudimentary. Apothecia usually borne 
 on, secondary branches, rarely on short stalks ; conflu- 
 ent. Disk convex or slightly concave, scarlet. 
 
 19. Cladonia gracilis. Primary thallus of rather 
 large scattering lobes, branching usually once or twice. 
 Podetia long, slender, variable, sometimes simple and 
 pointed, again more or less branching, sometimes bear- 
 ing rather small cups from which one or more branches 
 of considerable size develop. Apothecia medium, on 
 short stalks. Disk convex, brown. 
 
 20. Cladonia fimhriata. Primary thallus rather 
 large, more or less scattered, usually once or twice di- 
 vided, margin crenate. Podetia usually long, slender, 
 sparsely branched, sometimes terminating in a cup, 
 attenuately pointed, rarely bearing thalfoid lobules, 
 white, smooth or granular, becoming decorticate. Apo- 
 thecia terminal on small branches from the margin of 
 the cups, medium, confluent. Disk convex, brown. 
 
 21. Cladonia verticillata. Primary thalli sparingly 
 present. Lobes from small to medium, more or less 
 orbicular, scattering. Podetia from medium to very 
 
GENERA AND SPECIES. 99 
 
 long, rather slender, expanded, cup-like, bearing here 
 and there a few thalloid lobules, branches sometimes 
 formed on the cups or the margins of the cups. Apo- 
 thecia usually rare, on short stalks from the margins 
 of the cups, small to medmm. Disk convex, brown. 
 
 22. Cladonia squamosa. Primary thallus well de- 
 veloped, slender, elongated, variable in size and 
 frequency of branching. Podetia rather long and 
 slender, irregularly branched, branches decreasing in 
 length and thickness directly with the number of di- 
 visions, bearing many thalloid lobules. Apothecia 
 rather small. Disk convex, brown. Spores compara- 
 tively numerous, 12/x X 3.5^. 
 
 23. Cladonia turgida. Pr mary thallus large, 
 elongated, branched. Podetia long, rather thick, 
 irregularly branched, sometimes perforate. Apothecia 
 rare, small, hemispherical, on short slender branches. 
 Disk light reddish-brown. Spores very rare. 
 
 24.' Cladonia uncialis. Primary thallus deficient 
 or wanting. Podetia in dense clusters, much ex- 
 panded, branching, more or less perforate, terminal 
 branches pointed, usually sterile. " Podetia incras- 
 sated above, cymose, brown." 
 
 25. Cladonia furcata. Primary thallus consisting 
 of a few small scattering lobes, sometimes becoming 
 large, and indistinctly branched. Podetia long, rather 
 slender, frequently branched (thickness and length of 
 branches decreasing with the number of divisions), 
 smooth, whitish, bearing thalloid lobules. Apothecia 
 from small to medium. Disk convex, brown. Spores 
 rather large (long). 
 
100 GUIDE TO THE STUDY OF LICHENS. 
 
 26. Cladonia leporina. Primary thallus rare. 
 Lobes narrow and much branched, quite rigid. 
 Podetia rather long, distinctly and uniformly twice 
 branched, quite smooth. Apothecia small. Disk 
 convex, scarlet. 
 
 27. Cladonia amaurocroea. Primary thallus de- 
 ficient or wanting. Podetia long, slender, much 
 branched, terminal branches not bearing sperma- 
 gonia are pointed. Apothecia rather small. Disk 
 flat or slightly concave, margin and a central portion 
 often somewhat elevated, reddish-brown. Spores 
 lOya X 4.5/x. 
 
 28. Cladonia rangiferina. Primary thallus often 
 wanting. Podetia long and rather slender, frequently 
 branching, smooth, greenish to ash-gray, terminal 
 branches short, somewhat recurved. Apothecia are 
 frequently wanting, small, simple. Disk convex, 
 brown. 
 
 " Crabbe calls it truly, 
 
 "'The wiry moss that whitens all the hill/ 
 
 " ' Omnium lichenum copiosissima,' according to 
 Fries, — it is almost a cosmopolite, but its geo- 
 graphical range is, in various parts of the world, very 
 irregular and limited. In Northern Europe it is used, 
 like Certaria Islandica, as a nutrient and demulcent. 
 It is a social plant, covering in Lapland vast tracts of 
 country, and growing to a height of six to twelve 
 inches. The barren plains so covered are the favor- 
 ite and only pasture of the reindeer during winter; 
 the animals clear away the snow by means of their 
 
GENERA AND SfEClES. 101 
 
 horns to browse on the lichen. It is also frequently 
 collected, like hay, as fodder for cattle during winter 
 and for the reindeer on journeys. Parry, in the nar- 
 rative of his fourth voyage, mentions his officers col- 
 lecting supplies of this lichen as provender for the 
 reindeer, which he used in the capacity of horses ; he 
 adds, ' It required a great deal of picking * to separ- 
 ate it from the moss, among which it usually grows. 
 The daily quantity of cleaned 'reindeer moss' — as 
 it is popularly denominated — necessary for each ani- 
 mal on a journey is four pounds ; but, he remarks, it 
 can easily remain for five or six days without food. 
 To prepare it as fodder for cattle, in some northern 
 countries, hot water is poured over it ; it is then 
 mixed with straw, and a little salt sprinkled over the 
 mixture. Cattle so fed are said to produce delicious 
 milk and butter, while their flesh becomes fat and 
 sweet. Bucke, in his ' Harmonies of Nature,' speaks 
 of small cows, by feeding on this lichen, whose milk 
 becomes wholly cream. The stag, deer, roebuck and 
 other wild animals also feed on it abundantly during 
 winter. But it is not only serviceable as food to the 
 lower animals, — man himself is frequently compelled 
 to use it in times of scarcity. It is sometimes pow- 
 dered, mixed with flour and baked into bread ; or it 
 is boiled in milk or broth. Clarke, in his ' Travels,' 
 mentions having eaten it, and even speaks of it in a 
 commendatory way. It is sold by the London herbal- 
 ists for the purposes of the bird-stuffer. In a pulver- 
 ized state it at one time formed a frecjueut ingredient 
 in hair-powders and perfumes." — Lindsay. 
 
102 GUIDE TO THE STUDY OP LICUeNS. 
 
 5. Thamnolia. 
 
 This genus is represented by one species only. It 
 is quite probable that it belongs to Oladonia ; in fact, 
 that is the position given it by many lichenologists. 
 
 The primary thallus is wanting. The podetia are 
 quite free from warts or excrescences, hollow, simple 
 or sparingly branched. They are widest at the bot- 
 tom, gradually tapering upward, a character not oc- 
 curring in the simpler podetia of Cladonia. Color 
 varies from greenish-gray to pale straw-color. 
 
 No apothecia have been found ; it is propagated by 
 means of soredia, and also vegetatively. 
 
 It occurs upon rock and soil in the higher altitudes 
 and latitudes. 
 
 1. Thamnolia vermicularis. Primary thallus want- 
 ing. Podetia rather long, usually simple, sometimes 
 one or more short branches toward the apex, thin, 
 tapering, sometimes wrinkled longitudinally, color as 
 above. No apothecia, and hence no spores. 
 
 III. LECIDEACE^. 
 
 Stipes and podetia are wholly wanting in this 
 family, which distinguishes it from the preceding 
 families. The apothecia are sessile upon the thallus, 
 discoid, and belong to the fungal type. The disk is 
 generally convex or flattened. The thallus varies 
 from crustose to distinctly foliose, never fruticose. 
 The foliose thalli are entire, not distinctly lobed or 
 branched. 
 
 It must be stated that considerable doubt exists as 
 to the exact limitations of this family. Some of the 
 
GENERA AND SPECIES. 103 
 
 t 
 
 lower genera here included present widely different 
 spore-chanicters, which would perhaps indicate a re- 
 moter relationship than is assumed. In some instances 
 the thallus is very rudimentary. Because of the ab- 
 sence of well-marked family-characters, the amateur 
 is likely to confuse some of the lower genera with the 
 lower genera of the ParmeliacecB, and perhaps some 
 Verrucariacece, to be considered later. 
 
 KEY TO THE GENERA. 
 Thallus indistinctly crustose to Avarty. 
 Spore-sacs bearing sixteen simple colorless spores, 
 
 o , . . , 1- Biatorella. 
 Spore-sacs bearing eight spores (usual number). 
 Hypothecium and spores colorless. 
 Spores elliptical. 
 
 Two-celled ^. Biatorina. 
 
 ^^'"P^e s. Biatora. 
 
 Four-celled ^. BiUmbia. 
 
 bpores acicular, six to eight-celled . .5. Bacidia. 
 Hypothecium dark. 
 Spores colorless. 
 
 Simple 6. Lecidea. 
 
 Two-celled 7. CatiUaria. 
 
 Four-eel ed g. Cdidiopsis. 
 
 Spores dark. 
 
 Two-celled 5. BnelUa. 
 
 Four-celled , jO. Buellopsis. 
 
 bpore-sacs bearing from one to six spores, hypothecium 
 colorless or yellowish. 
 
 Spores simple, colorless, large . . 11. Megahspora. 
 Spores multilocular.i 
 
 ^^^^: 1^. Lopadium. 
 
 rry. 11 F?-'"''''''' ^3- Gyalecta. 
 
 Thallus fohose, entire. 
 
 Small, adnate to substratum, spores simple, colorless, 
 T , .,. ^4- Psora. 
 
 -Large, umbilicate ; apothecia black, sessile. 
 
 Spores simple, colorless 15. Gf/rophora. 
 
 Spores multilocular, large .... 16. Umbilicaria. 
 
 -^.^^/''""l'-'*'*'"'^'".''^"*'^^" '» nieant many celled spores havine 
 ■epta formed m two plants of thespore. i^v.icb imviug 
 
104 GUIDE TO THE STUDY OF LICHENS. 
 
 1. Biatorella. 
 
 A very insignificant group ; only one species has 
 come to my notice. The thallus is very rudimentary 
 or entirely wanting ; repeated search is necessary to 
 detect the algae (Protococcus). The apothecia are 
 small, dark and considerably scattered, which adds to 
 the difficulty of finding specimens. The spores are 
 simple, small and colorless, sixteen usually occurring 
 in each spore-sac. 
 
 The Biatorellas seem to prefer sterile soil. 
 
 1. Biatorella geophana. Thallus deficient or want- 
 ing. Apothecia small. Disk convex, dark-brown. 
 Spores simple, nearly spherical, colorless, 8/a X 7/x. 
 
 2. Biatorina. 
 
 This genus is likewise deficient in representatives. 
 The thallus is rudimentary but readily recognizable ; 
 it is usually greenish in color and uniformly crustose, 
 never becoming warty or areolate. The algae are 
 bright-green, occurring in chains of rather small cells 
 (^Chroolepus umhrina). The apothecia are quite 
 small. Disk flattened or slightly concave, brown or 
 even pale-brown. Some authors combine this group 
 with Biatora ; but the elliptical, colorless, two-celled 
 spores exclude it. They occur upon soil, tree-trunks 
 and moss. 
 
 1. Biatorina lutea. Thallus thin, evenly spread- 
 ing, somewhat granular, light-gray to greenish. 
 Apothecia rather small, discoid. Disk of a yellow- 
 ish waxy color. Spores colorless, elliptical, two-celled, 
 15/* X 5/x. 
 
GENERA AND SPECIES. 105 
 
 ^. Biatorina pineti. Th alius very rudimentary, 
 dark. Apothecia very small. Disk dark. Spores 
 as in B. lutea. 
 
 B. lutea occurs upon moss, while B. pineti occurs 
 upon pine trees. Both are quite rare. 
 
 3. Biatora. 
 
 This genus is represented by a considerable num- 
 ber of species. Some authors have made it the 
 dumping ground for many lichens which have no 
 evident affinity to the typical representatives. Thus, 
 for example, Biatorella, Biatorina, Bilimhia, Bacidia, 
 Psora, Acarospora, etc., have been included in Bia- 
 tora, and are yet so included by some recent authors. 
 This is no doubt primarily due to insufficient attention 
 to spore-differences. 
 
 The thallus varies from typically crustose to warty 
 and minutely foliose. The color tends toward gray- 
 ish-green. The algae are Protococcus (^Cystococ- 
 cus). 
 
 The apothecia are of medium size, discoid. Disk 
 flattened to convex, light-brown to dark and black. 
 The hypothecium is colorless. Spores are elliptical, 
 simple, colorless. 
 
 The Biatoras are widely distributed, and occur upon 
 bark, less commonly upon rock and moss. They are 
 active in the disintegration of rock, but much less so 
 than their near relatives, the Lecideas. 
 
 The following are the more common species. 
 
 1. Biatora varians. Thallus thin, granular, gray- 
 ish-green ; margin dark. Apothecia small, sessile, 
 
106 GUIDE TO THE STUDY OF LICHENS. 
 
 irregular margin. Disk yellowish to brown. Spores 
 ovoid or nearly spherical, colorless, 7fx to 1 Ofx. 
 
 This species has many characters peculiar to the 
 lower Lecanoras, which would make it seem proper to 
 place it with that group. 
 
 2. Biatora myriocarpoides. Thallus thinly crus- 
 tose and of a dark muddy color. Apothecia small, 
 sessile. Disk flat or slightly convex, dark. Spores 
 elliptical, colorless, 8.5//, to 9/x. 
 
 The hypothecium is generally dark or even black, 
 which would point toward the Lecideas ; but the 
 color variations of the hypothecium are, however, 
 too great to be reliable as a generic character. 
 
 3. Biatora uliginosa. Thallus consists of minute 
 granular elevations, color varies from gray to dark or 
 black. Apothecia small, few in number. Disk flat- 
 tened, sometimes convex, dark color. Spores ellipti- 
 cal, colorless, rarely two-celled, 22/a X 8/x. 
 
 Jf. Biatora contigua. Thallus evenly spreading, 
 scaly or squamose, light-gray. Apothecia compara- 
 tively large, numerous, sessile. Disk convex, some- 
 times flattened, black with a translucent white film 
 which is characteristic of the species. Spores ellip- 
 tical, colorless, 22^ X ^/x. 
 
 5. Biatora diapensice. Thallus rudimentary, color 
 whitish. Apothecia of medium size. Disk generally 
 convex, reddish-brown or black. Spores colorless, 
 elliptical, 10/i, X 3.5yu,. 
 
 The hypothecium is occasionally blac^:, and this 
 plant may, therefore, be mistaken for a species of 
 Lecidea. 
 
GENERA AND SPECIES. 107 
 
 <J. Biatora vernalis. Thallus thin, granular, gray 
 to greenish. Apothecia variable in size, sometimes 
 in clusters. Disk yellowish to tawny, sometimes 
 black. Spores elliptical to oblong, often indistinctly 
 two-celled, colorless, 15/a X 7/x,. 
 
 7. Biatora russiila. Thallus granular, ash-gray to 
 greenish. Apothecia small to medium. Disk flat or 
 convex, brick-red. Spores colorless, oblong, some- 
 times indistinctly two-celled, 11/t X 8.5/x. 
 
 8. Biatora petiaspis. Thallus indistinct, dark-brown 
 to black. Apothecia medium size. Disk varying from 
 grayish to black. Spores variable in size and form, 
 simple, colorless, averaging 10/x X 4.5/x,. 
 
 The hypothecium is often brown to dark in color, 
 perhaps never entirely black. 
 
 9. Biatora parvifolia. Thallus usually distinct, 
 minutely thalloid or scaly, pale-green to yellowish- 
 green or even reddish-brown. Spores oblong, color- 
 less, simple, 14/x by 4/x. 
 
 As the name (^parvifolia) indicates, this is in reality 
 a foliose lichen, but the lobes are so insignificant 
 that the average collector will take it for a crustose 
 lichen. 
 
 10. Biatora granulosa. Thallus distinct, of gray- 
 ish-white, smooth wart-like elevations which often bear 
 greenish soralia.* Apothecia of medium size. Disk 
 convex, usually black, sometimes dark-brown or red- 
 dish. Spores variable in size and form, simple, color- 
 less or faintly yellowish-brown, IG/x X 7/x,. 
 
 11. Biatora cinnaharina. Thallus granular, con- 
 
 » Soralia are aggregates of soredi;i which may occur as circular or 
 linear patches. The word was iutroduced by Reinke (1895). 
 
108 GUIDE TO THE STUDY OF LICHENS. 
 
 sisting of numerous raiuute but distinct elevated gran- 
 ules, whitish to yellowish-green. Apothecia medium 
 size. Disk convex, bright-scarlet. Spores oblong, 
 often somewhat larger at one end, simple, colorless. 
 24/x X 4/x. 
 
 This species does not occur in the northeastern 
 United States. It is western and southern in its 
 range. 
 
 Jf. Bilimhia. 
 
 This is another insignificant group represented by 
 only a few species. Its general characters correspond to 
 those of the Biatoras and Lecideas. Various authors 
 include it under Biatora. 
 
 The thallus is crustose, never becoming foliose as in 
 some of the Biatoras. The apothecia are of medium 
 size. Disk flattened or convex, color yellowish-brown 
 to dark-brown. The algse are in all probability Proto- 
 coccus, but differ from the usual forms in their small 
 size. Spores are spindle-shaped, colorless, usually 
 four-celled. 
 
 The Bilimhias occur upon tree-trunks and moss. 
 
 1. Bilimhia mixta. Thallus granular, warty, whitish, 
 or faintly yellow. Apothecia small, adnate. Disk 
 convex, usually black. Spores oblong, two to four- 
 celled, colorless, sometimes slightly curved, 18/i, X 5/x. 
 
 2. Bilimhia hypnophila. Thallus granular, spread- 
 ing, greenish to gray. Apothecia small, sessile, un- 
 evenly convex. Disk black, thecium and hypothecium 
 reddish-brown. Spores as in B. mixta. 
 
 3. Bilimhia sphceroides. Thallus distinct, uniformly 
 spreading, granular, greenish, Apothecia nearly glo- 
 
GENERA AND SPECIES. 109 
 
 bose, attached by a narrow neck. Disk yellowish or 
 tawny. Spores as in B. mixta. 
 
 5. Bacidia, 
 
 This genus is represented by a considerable num- 
 ber of species and is well characterized, although some 
 authors include it under Biatora, no doubt because in 
 its gross characters it resembles that genus. 
 
 The thallus is typically crustose, sometimes becom- 
 ing indistinctly areolate or coarsely granular, color 
 gray to greenish. The alga? are Proto§occus. The 
 apothecia are of medium size. Disk convex to flat- 
 tened, light-brown to black ; the hypothecium varies 
 from dark-brown to nearly black. Tlie spores are 
 much elongated, acicular, more narrow toward one 
 end, colorless, five to eleven-celled, variable in size and 
 form. 
 
 This genus is southern in its range. They generally 
 occur upon tree-trunks, more rarely upon rock and 
 moss. 
 
 1. Bacidia albescens. Thallus thinly granular, green- 
 ish to gray. Apothecia small. Disk convex, pale-yel- 
 lowish or pale-brown. Spores very slender, indistinctly 
 septate, 35/t X 1.8//,. 
 
 2. Bacidia cuprea-rosella. Thallus granular to squa- 
 mose, light-gray to greenish-gray. Apothecia small. 
 Disk convex, yellowish to reddish-brown. Spores 
 comparatively short and thick, usually blunt at both 
 ends, five-celled, colorless, 17/x X 3/4,. 
 
 3. Bacidia chlorosticta. Thallus deficient, minutely 
 granular, gray to greenish. Apothecia very small. 
 
110 GUIDE TO THE STUDY OF LICHENS. 
 
 Disk convex, black. Spores small, slender, more or 
 less curved, five to seven-celled, colorless, 20/a X 1-5/x. 
 J,., Bacidia atrogrisea. Thallus granular, greenish 
 to gray. Apothecia rather small. Disk convex, 
 black. Spores nine to eleven-celled, pointed at both 
 ends, variable in length and width, colorless, 60/x 
 X 5/x. 
 
 5. Bacidia inundata. Thallus granular, or more 
 or less squamosa, greenish to gray. Apothecia small. 
 Disk convex, brown to black. Spores seven to nine- 
 celled, indistiiactly septate, colorless, 31/a X 2/x. 
 
 6. Bacidia rubella. Thallus of distinct, more or 
 less scattered granules, greenish to gray. Apothecia 
 of medium size. Disk reddish-brown to dark-brown. 
 Spores colorless, nine to eleven-septate, 50/x X 4/x. 
 
 7. Bacidia suffusca. Thallus thinly granular, green- 
 ish to ash-gray. Apothecia of medium size to quite 
 large, raised margin. Disk reddish-brown coated with 
 a translucent whitish film, giving it a characteristic 
 appearance. Spores seven to nine-celled, colorless, 
 50/x X V 
 
 8. Bacidia Schweinitzii. Thallus granular, form- 
 ing a thin crust, greenish to ash-gray. Apothe- 
 cia of medium size. Disk brown to black. Spores 
 colorless, seven to nine-celled, 55/x X 4/x. 
 
 6. Lecidea. 
 
 The representatives of this genus resemble the 
 Biatoras very closely, so much so in fact that it 
 would seem advisable to combine the genera. The 
 only essential difference seems to be the greater pre- 
 
28 
 
 J 
 
 I'LATi: I^. ( 'rust,, SI- Typfs. Kimi, il.,- r..ll,-,-t ion ut X. 
 V. ('l;irk 111 tli«' lifibaliiiiii «•! iln- ( aliloinia A.a.i»-iii> <'i 
 Science. Ltrhlta inh-i-nlfurti. 
 
GENERA AND SPECIE^. Ill 
 
 dominance of dark coloration in the Lecideas, espe- 
 cially in the disk and hypothecium. The Lecideas are 
 also more brittle. As in Biatora, the spores are sim- 
 ple, elliptical and colorless. 
 
 The majority of the species occur upon rock, some 
 upon trees and fences. They play a very important 
 part in the disintegration of rock. 
 
 The Lecideas have the widest range of distribution: 
 they occur at all latitudes and altitudes. Lecidca 
 geographica occurs far above the line of perpetual 
 snow ; it forms the last vegetation of the Andes, the 
 Himalayas and the arid peaks of Nova Zembla. 
 
 1. Lecidea panceola. Thallus consists of rather 
 thick, closely crowded squamules, which are convex 
 above and of irregular outline ; ash-gray to dirty 
 brown. Apothecia comparatively large ; sometimes 
 two or three are united. Disk convex, dark-brown to 
 black. Spores simple, colorless, elliptical, 14/a X 4.5/x. 
 
 2. Lecidea enteroleuca. Thallus granulose to in- 
 distinctly squamose, ash-gray to greenish. Apothecia 
 small to medium. Disk flattened, margin somewhat 
 raised, black. Spores simple, colorless, elliptical, 
 Ufx X 6/.. 
 
 3. Lecidea melancheima. Thallus coarsely granu- 
 lar, rugose or warty, gray or greenish-white. Apothe- 
 cia of medium size. Disk convex, black. Hypothe- 
 cium yellowish or faintly brown. Spores colorless, 
 simple, elliptical, 9/a X 3.5yu,. 
 
 Jf. Lecidea geographica. Thallus areolate, alter- 
 nately dark and yellow, producing a characteris'ic 
 effect faintly resembling a colored map. Apothecia 
 
112 GUIDE TO THE STUDY OF LlCHENS. 
 
 rather small, somewhat immersed, flattened. Disk 
 dark. Spores simple, colorless, elliptical. 
 
 7. 
 
 Another insignificant group having a close resem- 
 blance to Bilimbia and by some authors placed with 
 Biatora. It differs from Bilimhia in that the hypo- 
 thecium is dark. The genus requires further careful 
 study. Only a few species are reported. These occur 
 upon tree-trunks and moss. 
 
 1. Celidiopsis platycarpa. Thallus rudimentary, 
 granular, gray to greenish. Apothecia small, ele- 
 vated margin. Disk flattened, black. Spores color- 
 less, rather variable in size and form, four-celled, 
 22/x X V 
 
 8. Buelliopsis. 
 
 This genus is represented by a few species. It dif- 
 fers from Buellia in its spore-characters, otherwise it 
 is the same. The spores are four-celled, dark, con- 
 stricted at the transverse septa. 
 
 1. Buelliopsis vernicoma. Thallus granular, spread- 
 ing, gray to greenish. Apothecia small, elevated mar- 
 gin. Disk flattened, black. Spores dark-brown, dis- 
 tinctly four-celled, usually constricted at the septa, 
 16/x X 6.5/x. 
 
 9. Buellia. 
 
 The Buellias are well characterized, and are repre- 
 sented by a large number of species. The general char- 
 acters of the thallus resemble those of Biatora and 
 Lecidea. The apothecia are medium in size and are 
 
GEKERA AND SPECIES. 113 
 
 more or less irregular in outline. The spores are 
 normally two-celled, constricted at the middle, dark to 
 nearly black in color. 
 
 The BuelUas have a wide range, and occur upon 
 rocks, rarely upon trees and old fences. They are 
 found at very high altitudes. Formerly the BuelUas 
 were united with the Lecideas. Reinke considers 
 them closely related to Rinodina, 
 
 1, Buellia Schcsreri. Thallus granular to indis- 
 tinctly areolate, brownish. Apothecia very small. 
 Disk dark-brown to black. Spores two-celled, dark- 
 brown, not constricted, ends blunt, 12/x X 7yM. 
 
 2. Buellia parmeliarum. Thallus granular, green- 
 ish to ash-gray. Apothecia small. Disk convex, 
 black. Spores oblong, dark-brown, 12/a X 5/x. 
 
 This plant is said to be normally parasitic upon 
 species of Parmelia. The majority of plants found 
 upon Parmelia are, however, very likely parasitic 
 fungi, as in those examined no thallus could be 
 detected. 
 
 S. Buellia parasema. Thallus granular to more or 
 less irregularly areolate, areoles sometimes scattered, 
 gray. Apothecia medium to large, considerably ele- 
 vated above the surface of the thallus. Disk flat- 
 tened, margin somewhat elevated, black. Spores 
 two-celled, dark-brown, not constricted, sometimes nar- 
 rowed at one end and slightly curved, 14ya X 6/x. 
 
 4. Buellia dialyta. Thallus from thin and uni- 
 formly spreading to minutely granular, granules 
 often scattered, ash-gray. Apothecia small, somewhat 
 elevated above the thallus. Disk convex, black. 
 
114 GUIDE TO THE STUDV OF LICSENS. 
 
 Spores two-celled, sometimes constricted, large, dark- 
 brown, 24/A X lliW" 
 
 5. Buellia stellulata. Thallus of rather small, ir- 
 regular, scattered areoles. Apothecia very small, barely 
 extending above the surface of the thallus. Disk flat, 
 brown to black. Spores two-celled, not constricted, 
 ends blunt, 9/x X 5/x. 
 
 6. Buellia Eiizce. Thallus of minute, more or less 
 scattered granules, gray to greenish. Apothecia medium. 
 Disk reddish-brown to black. Spores in various stages 
 of development, two-celled and dark-brown when ma- 
 ture, 13/x X 7/A. 
 
 7. Buellia myriocarpa. Thallus thinly granular, 
 ash-gray to greenish. Apothecia small, numerous, 
 somewhat elevated above the thallus. Disk flat- 
 tened, black. Spores two-celled, dark-brown, 14/x 
 X 7/.. 
 
 8. Buellia colludens. Thallus of very small, closely 
 adnate, angular squamules with slightly depressed mar- 
 gins, gray to brownish. Apothecia small, variable in 
 form, somewhat elevated above the thallus. Disk flat- 
 tened, black. Spores two-celled, constricted, dark- 
 brown, lo/x X 6.5/x. 
 
 9. Buellia coracina. Thallus of comparatively large, 
 rather irregular squamules, with upper surface more or 
 less convex, dark to nearly black. Apothecia of me- 
 dium size, adnate upon the thallus. Disk convex, dark 
 to black. Spores two-celled, not constricted, dark- 
 brown, 15/x X 8yu,. 
 
 10. Buellia hadia. Thallus of small, angular, closely 
 adnate squamules, tawny to brownish. Apothecia 
 
GENERA AND SPECIES. 115 
 
 small, immersed. Disk flattened, black. vSpores two- 
 celled, brownish when mature, 8/a X 4.5/x. 
 
 11. Buellia spuria. Thallus of rather large angu- 
 lar squamules, somewhat convex above with dark mar- 
 gin, light to gray. Apothecia of medium size, adnate, 
 only slightly extending above the thallus, irregular in 
 form and size, often covering the entire squamule, mar- 
 gin somewhat elevated. Disk black. Spores two- 
 celled, dark-brown, 15/a X 7/x. 
 
 12. Buellia pulchella. Thallus well developed, con- 
 sisting of gyrate folds, resembling the convolutions of 
 the brain, greenish-yellow. Apothecia medium to 
 large, sessile. Disk convex, black. Spores two-celled, 
 constricted, dark-brown, 14/x X 7/w,. 
 
 10. Catillaria. 
 
 This genus requires further careful study. Tucker- 
 man and others included it in the uncertain group 
 Heterothecium. Its general characters resemble those 
 of Lecidea. The hypothecium is dark-blue to black. 
 Thallus is rudimentary. The algae are no doubt Pleu- 
 rococcus. Spores two-celled, large, colorless. Only 
 one species from the United States has come to my 
 notice. 
 
 1. Catillaria grossa. Thallus thin, papery, smooth, 
 almost shining. Apothecia medium in size. Disk 
 flattened, margin elevated, black. Spores two-celled, 
 colorless, large. 
 
 C. grossa occurs upon bark of ash and perhaps other 
 trees. It is not common, and nothing definite is known 
 concerning its distribution. 
 
116 GUIDE TO THE STUDY OF LICHENS. 
 
 11. Megalospora. 
 
 This genus has also been included under Heterothe- 
 cium. Its general characters are like those of Gatil- 
 laria; the apothecia are somewhat larger and the 
 disk more convex. The thallus presents almost the 
 same external appearance as to color and general con- 
 formation ; the algae are, however, Protococcus instead 
 of Pleicrococcus. The hypothecium is black or blue- 
 black. Each spore-sac contains one, rarely two, large 
 simple spores. The spore-wall consists of two layers, 
 of which the outer one is quite thick and gelatin- 
 ous. 
 
 1. Megalospora sanguinaria. Thallus light-gray. 
 Apothecia comparatively large. Disk convex. Spores 
 large, simple, colorless, outer spore-wall (exosporium) 
 thick, 103^ X 4:0/x. 
 
 The above is the only species which came to my no- 
 tice. It is not very common and occurs upon trees. It 
 seems to be northern in its range. 
 
 12. Lopadium. 
 
 This genus is also taken from the conglomerate 
 group Heterothecium. The thallus is crustose and uni- 
 formly spreading. The algae are Chroolepus umhrina. 
 Soralia are common. The apothecia are of medium 
 size, loosely sessile upon the thallus, discoid. A red- 
 dish-brown or nearly black color pervades almost the 
 entire apothecial structure. The spores are multiloc- 
 ular, large, and vary from colorless to brown and red- 
 dish-brown. 
 
 A few species are reported which seem to be 
 
GENERA AND SPECIES. 117 
 
 southern in their range. They occur upon trees and 
 mosses. 
 
 1. Lopadium pezizoideum. Thallus granular, uni- 
 formly spreading, thin, grayish. Apothecia of medium 
 size, discoid, not numerous. Disk convex, dark. Spores 
 large, one in each spore-sac, colorless, and simple in 
 early stages of development, multilocular and dark 
 when mature, 90/x X 35/a. 
 
 13. Gyalecta. 
 
 This is one of the older genera, and hence it would 
 bfi reasonable to assume that it is well understood, but 
 such is not the case. A large number of herbarium 
 specimens labelled as Gyahctas belong to other gen- 
 era. It is in fact impossible at the present to give 
 the exact limitations of the genus. The following 
 are some of the generic characters, as far as they 
 could be determined. 
 
 The thallus is crustose in the majority of species ; 
 becoming minutely foliose in the higher species, 
 color generally dark. The algie are Protococcus, 
 Apothecia are discoid. Disk is flattened to some- 
 what cup-shaped, dark. The hypothecium is usually 
 colorless. The spores are quite large and multilocu- 
 lar, oblong to spindle-shaped, usually colorless, though 
 some are evidently dark in color. 
 
 They occur upon rock and trees. Nothing definite 
 can be stated as regards range and frequency of occur- 
 
 rence. 
 
 1. Gyalecta cupularis. Thallus crustose, evenly 
 spreading, gray to dark. Apothecia discoid. Disk 
 
118 GUIDE TO THE STUDY OF LICHENS. 
 
 concave, reddish-brown, margin somewhat rugose. 
 Spores multilocular, somewhat colored when mature, 
 
 40/A X 20/x. 
 
 IJf. Psora. 
 
 By some authors this genus is classed with Biatora, 
 others class it with Lecanora. It is the first group 
 of the LecideacecB in which the thallus is typically 
 foliose. The thallus is simple, entire, small, and is 
 usually closely adnate to the substratum, or the entire 
 lobes may be plicate or ascending. The lobes never 
 became large, scarcely exceeding one-fourth of an 
 inch in diameter. They are, however, comparatively 
 thick, thus giving them considerable rigidity. Their 
 color is quite variable ; the upper surface varies from 
 light-gray to black ; the lower surface is usually of a 
 lighter color. 
 
 The apothecia are small to medium, distributed 
 over the thallus, but sometimes ranged about the 
 margin. They are somewhat discoid and more or less 
 immersed in the thallus. The disk is dark-colored 
 (rusty). The spores are simple, elliptical, colorless, 
 closely resembling those of Biatora. 
 
 The Psoras occur upon rock and soil ; they seem to 
 be quite generally distributed. 
 
 1. Psora icteria. Thallus-lobes rather small, 
 scarcely ascending, margin somewhat crenate and 
 light colored ; upper surface greenish becoming 
 tawny with age ; light colored beneath. Apothecia 
 rather small, sessile. Disk nearly black. Thecium 
 and hypothecium yellowish. Spores simple, color- 
 less, elliptical, 16/x X 7/x. 
 
GENERA AND SPECIES. 119 
 
 2. Psora atro-rufa. Thallus of rather small lobes, 
 margin more or less crenate and lobulate, closely 
 adnate to the substratum, color dark. Apothecia 
 medium, sessile, disk slightly convex, dark. Spores 
 simple, colorless, elliptical, 14/a X 5/x. 
 
 3. Psora rufonigra. Thallus-lobes rather small, 
 somewhat ascending, margin wavy and lobulate, 
 upper surface dark reddish-brown to nearly black. 
 Apothecia medium to large, marginal. Disk convex, 
 black. Spores colorless, simple, elliptical, 12/x X 'V- 
 
 4. Psora decipiens. Thallus-lobes usually ascend- 
 ing, closely crowded, margin more or less crenulate, 
 lobed, turned back and white ; upper surface brown 
 to tawny ; white beneath. Apothecia much as in P. 
 icteria. Spores simple, colorless, elliptical, 14/x X C/x. 
 
 5. Psora RusselUi. Thallus-lobes rather large, 
 entire, quite thick and rigid, margin somewhat cre- 
 nate, white, slightly turned up ; upper surface brown- 
 ish, lower surface light color. Apothecia of medium 
 size, usually marginal. Disk convex, brown. Spores 
 simple, colorless, elliptical, 11/x X 4.5/a. 
 
 15. Gyrophora. 
 
 The representatives of this genus are highly inter- 
 esting, both as to size and form and as to the eco- 
 nomic uses to which they have been put in the past. 
 
 The thallus is typically foliose, and varies in size 
 from medium to very large. The smaller thalli may 
 either be single or form a cluster, more or less imbri- 
 cate. No matter what the size of the thallus may be, 
 it is always entire and held to the substratum by 
 
120 GUIDE TO THE STUDY OF LICHENS. 
 
 the umbilicus. The margin is generally somewhat 
 torn. The prevailing color of the upper surface is 
 gray to nearly black ; the lower surface is quite 
 black, bearing black rhizoids or scaly lamina. 
 
 The apothecia are rather peculiar in structure. 
 They are sessile upon the thallus, and on examina- 
 tion with a pocket-lens the disk presents a convo- 
 luted appearance, reminding one of the convolutions 
 of the dentine in the tooth of a ruminant. The disk 
 is convex, black. The spores are simple, elliptical, 
 colorless. 
 
 The Gyrophoras are northern in their range, but 
 are also quite common in the mountainous regions of 
 the temperate and torrid zones. They grow upon 
 rock and soil. Quite generally this group is com- 
 bined with Umhilicaria. 
 
 1. Gyrophora hyperhorea. Thallus medium, nearly 
 entire, margin somewhat incised and torn, rugose 
 above, dark to black; usually smooth and some- 
 what lighter below. Apothecia small to medium. Disk 
 flattened, black. Spores ovoid, colorless, somewhat 
 curved, 14/x by 7/u,. 
 
 2. Gyrophora prohoscidea. Thallus medium size, 
 somewhat lobed or folded, and rugose above, margin 
 torn and occasionally perforate, bearing cilia, gray, 
 dark near margin ; lower surface pale toward centre, 
 becoming darker toward margin. Apothecia of me- 
 dium size, scattered over the thallus, except at the 
 centre and margin. Disk flattened, black. Spores 
 simple, colorless, elliptical or ovoid, slightly curved, 
 16ft X 7ft. 
 
GENERA AND SPECIES. 121 
 
 According to Porcher, Icelanders use this lichen as 
 an article of food ; more frequently for dyeing woollen 
 cloth a brownish-green color. 
 
 3. Gyrophora erosa. Thallus medium in size, more 
 or less lobed, margin ragged and reticulately perforate, 
 entire upper surface more or less reticulate, dark color ; 
 lower surface fissured, areolate, lighter than upper sur- 
 face. Apothecia small. Disk convex, black. Spores 
 small, colorless, granular, lO/x X 4.5/x. 
 
 4. Gyrophora floculosa. Thallus small to medium, 
 thin, margin somewhat lobed and torn ; upper surface 
 dark-brown, bearing numerous fine thalloid outgrowths ; 
 lower surface of nearly the same color and reticulately 
 veined. No fertile specimens have come to my notice. 
 
 5. Gyrophora Muhlenhergii. Thallus medium to 
 large, margin more or less torn ; upper surface smooth, 
 pitted and rugosely folded, ash-gray, darker toward 
 the margin ; lower surface more or less reticulate, 
 fringed toward the margin, dark-brown. Apothecia 
 from medium to large, situated in pits, scattered toward 
 the margin of thallus. Disk convex, black. Spores 
 simple, elliptical, colorless, 10/x, X 5^. 
 
 This is one of the lichens known as " tripe de roche," 
 and was used by Sir John Franklin on his journey to 
 the polar seas. It was said to be " agreeable and nu- 
 tritious," although, like other lichens, it contains an 
 objectionable bitter principle. 
 
 6. Gyrophora vellea. Thallus large, entire, margin 
 more or less incised and somewhat broken or torn, 
 upper surface smooth or finely powdered, gray ; lower 
 surface brown to dark, bearing numerous rigid cilia. 
 
122 GUIDE TO THE STUDY OF LICHENS. 
 
 Apothecia in slight depressions of thallus, marginal, 
 small to medium. Disk convex, black. Spores sim- 
 ple, colorless, elliptical, slightly granular, 10/x by 7/x. 
 
 " Some varieties of this species are imported to a 
 considerable extent into the London market from the 
 Norwegian mountains, for the manufacture of orchill 
 and cudbear, under the name of * Norway rock moss/ 
 or 'velvet or velutous moss.' Like most of its co- 
 species, it grows chiefly on granitoid rocks on very 
 high mountains, or in arctic or sub-arctic regions. On 
 the Mexican volcano of Orizabo it occurs at a height 
 of between 13,000 and 14,000 feet, along with other 
 species. This is another of the lichens which consti- 
 tute the ' tripe de roche ' of sub-arctic America and the 
 polar regions. This black, leathery, forbidding-look- 
 ing ' rock- tripe ' is often boiled and eaten by the Cana- 
 dian hunter when pressed by hunger. In Iceland it is 
 frequently eaten in periods of scarcity as a supplement 
 to the more nutritious ' Iceland moss ' ; and it has 
 been frequently mentioned in the narrative of the 
 polar voyages as having been the means of saving the 
 crew from perishing by starvation. The nutritive 
 properties of these lichens depend on the presence of 
 a large amount of starchy matter (lichenin, lichen- 
 starch). "When boiled they yield, like Cetraria Island- 
 ica, a firm, nutrient jelly, which is, however, accom- 
 panied, as in that lichen, by a bitter principle possessed 
 of purgative properties. Linnaeus speaks of some Gy- 
 rophoras as superior in nutritive qualities to the ' Ice- 
 land moss.' " — Lindsay. 
 
 7. Gyrophora Dillenii. Thallus large to very 
 
GENERA AND SPECIES. 123 
 
 large, entire, margin somewhat lobed or torn ; upper 
 surface smooth, centre raised, gray to brown; lower 
 surface dark. Apothecia medium to large, scattered, 
 convex, black. Spores large, colorless, simple, very 
 granular, ovoid, not curved, 24/x X 12/x. 
 
 16. Umhilicaria. 
 
 The general appearance and structure of the thallus 
 and apothecia of Umhilicaria shows its close relation- 
 ship to Gyrophora. It differs, however, in that rhi- 
 zoids, cilia and scaly plates (lower surface) are want- 
 ing. Coloration is the same in both. In Umhilicaria 
 the thallus is more or less pustular. The important 
 distinguisliing characters occur in the spores, wliich in 
 this genus are large, brown-colored, multilocular, each 
 spore-sac bearing a single spore. 
 
 The algae in Gyrophora and Umhilicaria are evi- 
 dently Protococcus, though they differ in form from 
 those occurring in other lichens ; further investigation 
 may prove it another alga. 
 
 The range and habitat of this group is much as 
 that of the preceding. It is represented by fewer spe- 
 cies. When dry, these lichens are very brittle, hence 
 the collector will find it necessary to gather them 
 when the atmosphere is moist, or to pour water upon 
 them before attempting to remove them from the rock 
 upon whicli they grow. 
 
 1 Umhilicaria papulosa. Thallus medium to 
 large, thin, margin more or less lobate and torn; 
 pustular, pustules quite separate and uniform in size ; 
 dark-gray above; lower surface reticulately pitted. 
 
124 GUIDE TO THE STUDY OF LICHENS. 
 
 smooth, colored much as upper surface. Apothecia 
 small, scattered over greater portion of thallus. 
 Disk flattened, black. Spores one, rarely two, 
 light-brown to dark-brown, multilocular, elliptical, 
 71/Lt X 3V 
 
 2. Umhilicaria Pennsylvanica. Thallus medium 
 to large, thin, more or less wavy, margin somewhat 
 torn ; pustules much as in U. papulosa ; dark-gray 
 above ; black and reticulately fitted below. Apothe- 
 cia large, elevated margin. Disk flat, black. Spores 
 68/x, X 27/x, otherwise as in U. papulosa. 
 
 3. Umhilicaria pustulata. Resembles U. papulosa 
 with the exception that the pustules are larger, con- 
 fluent; lower surface more reticulately pitted. Apo- 
 thecia more numerous and showing a tendency to 
 coalesce. Spores as in U. papulosa. 
 
 " According to Linnasus, a beautiful red color may 
 be prepared from this lichen, and it may be converted 
 into ' an exceeding fine black paint ' " — Porcher. 
 
 IV. GRAPHIDACEyE. 
 
 In all probability the family is out of its natural 
 position as here given. The reason that it is placed 
 above the LecideacecB is because it was believed that 
 Rocella should be included in the family, in accord- 
 ance with the views held by Reinke. It is, however, 
 probable that Rocella belongs to the Parmeliacece. 
 If the exclusion is admitted, the Graphidacece are 
 lowly organized lichens, in which the thallus never 
 develops beyond the crustose stage, and hence the 
 family would really be placed before the Caliciacece, 
 
GENEKA AND SPECIES. 125 
 
 The present classification will, however, be retained, 
 although RoceMa will be included under Parmeliacece. 
 The Graphidacece are essentially southern in their 
 range, where they also attain their maximum devel- 
 opment ; particularly is this true of Graphis and 
 Arthonia. The thallus is crustose and quite variable 
 in color and thickness. In a large per cent, of the 
 representatives the thallus is hypophloeodal, that is, it 
 occurs below the surface of the substratum and is 
 therefore invisible to the naked eye. The apothecia 
 are characteristic ; instead of being discoid, as in the 
 majority of lichens, they are linear, stellate or ir- 
 regular in outline. They belong to the fungal type. 
 
 KEY TO THE GENERA. 
 
 Spores two to eight-celled or simple, colorless. 
 
 Two-celled 1. Hazslinskya. 
 
 Four to six-celled, elliptical 2. Onegrapha. 
 
 Eight-celled, large, oblong, curved . . . 3. Graphis. 
 
 Simple 4. Xijlographa. 
 
 Four-celled, one end narrowed .... 5. Arthonia^ 
 Spores multilocular. 
 
 Constricted in the middle 6. Mycoporum. 
 
 Not constricted, colorless 7. Art hothel turn. 
 
 1. Hazslinskya. 
 
 A lowly organized group having only a few repre- 
 sentatives. The thallus, as well as the apothecia, 
 begin their development below the surface of- the sub- 
 stratum. The algae are Chroolepus. The apothecia 
 soon break through and appear as minute black dots ; 
 upon examination with a lens they are seen to be 
 more or less orbicular or somewhat elongated, with 
 1 Some of the southern Arthonias have colored spores. 
 
126 GUIDE TO THE STUDY OF LICHENS. 
 
 irregular outline. The disk * is flattened and dark in 
 color. The spores are colorless, of medium size, two- 
 celled ; one cell larger, constricted at the septum. 
 
 1. Hazslinskya demissa. Thallus partly below the 
 substratum, rudimentary, light color. Apothecia 
 oval, irregular in outline ; single, not in groups, as in 
 the European form H. gibherulosa^ opening by an 
 oval pore. Disk dark. Spores colorless, two-celled, 
 constricted at the septum, one cell larger, 17/a X 8/x. 
 
 This lichen is usually classified as Opegrapha de- 
 missa. 
 
 2. Opegrapha. 
 
 Thallus rudimentary and mostly hypophloeodal, 
 finally forming a thin film over the substratum. 
 The algae are Chroolepus. The apothecia are usually 
 numerous, small, linear, more or less curved, pro- 
 jecting somewhat above the surface of the substratum. 
 Disk black. The hypothecium is also black. The 
 spores are colorless, elliptical to almost acicular, usu- 
 ally four-celled. They occur upon trees. 
 
 1. Opegrapha varia, Thallus finely pulverulent, 
 light-colored, mostly hypophoeodal. Apothecia ellip- 
 tical, oblong to short-linear. Disk black. Spores 
 are four to six-celled, colorless to pale yellow, 
 23/x X 2.5/x. 
 
 2. Opegrapha vulgata. Thallus rudimentary, whit- 
 ish. Apothecia elliptical to distinctly linear, rather 
 small. Spores acicular, indistinctly four to six- 
 celled, colorless, 24/x X 2.5/x. 
 
 1 The term " disk " is scarcely applicable to the irregular apothecia 
 of this family, but will be retained to avoid the necessity of intro- 
 ducing a new term. 
 
I'LA'i'K Ir(. Cnistose Types. From i\\v coiit'cuoii ni X. 
 V. (lark ill ilic lit'ibariiim of Llie Calit'oniiu Academy «'t 
 Science. li'rdiiJiis scrijiln. 
 
GENERA AND SPECIES. 127 
 
 3. Graphis. 
 
 This gBDus is well represented in the southern 
 states. The thallus is always crustose, though it may 
 attain considerable thickness. The thallus, as well as 
 the apothecia, begins development below tlie surface 
 of the substratum, but soon breaks through after which 
 the thallus rapidly spreads. The algae are Chroolepus. 
 
 The apothecia are distinctly linear, often branching, 
 bent or angular. The disk is black in the northern 
 species, black or white in the southern forms. The 
 color of the thallus also varies from greenish-gray to 
 white. The spores are comparatively large, six to 
 twelve-celled, colorless, somewhat curved ; the more or 
 less gelatinous exosporium is wavy in outline. 
 
 The species occur upon trees, preferably the smoother 
 barks. 
 
 1. Graphis elegans. Thallus hypophloeodal. Apo- 
 thecia linear, branching, prominent. Disk black. Usu- 
 ally sterile. 
 
 This lichen closely resembles G. scripta and is, per- 
 haps, merely a varietal form of that species. 
 
 2. Grapliis scripta. Thallus hypophloeodal. Apo- 
 thecia as in G. elegans, less prominent. Spores eight- 
 celled, colorless, variable in size, 34/x, X H/^* 
 
 This lichen is common everywhere. 
 
 3. Graphis dentritica. Thallus rarely becoming 
 epiphloeodal at maturity. Apothecia radially linear 
 and branching. Disk black. Spores colorless, usually 
 eight-celled, one end often narrowed, 24/x X 6.5/x. 
 
 4' Graphis eulectra. Thallus soon becomes epi- 
 phloeodal, light-gray to nearly white, evenly spreading. 
 
128 GUIDE TO THE STUDY OF LICHENS. 
 
 smooth. Apothecia linear, branching, partially en- 
 closed by the thallus. Spores colorless, eight-celled, 
 30/x X 8.5^. 
 
 Jf.. Xylographa. 
 
 The thallus begins its development below the sur- 
 face of the substratum, finally spreading over the sur- 
 face in the form of a thin whitish layer. The algae 
 0,re Chroolepus and Protococcus. The apothecia are 
 linear or irregular, extending parallel to the fibres of 
 the woody substratum. The disk is dark. The hypo- 
 thecium is nearly colorless. The spores are rather 
 small, simple, elliptical, colorless and usually sparingly 
 present. 
 
 They occur upon rotten logs and bark of trees. 
 
 1. Xylographa parallella. Thallus becomes epi- 
 phloeodal at an early period, smooth, uniform, light- 
 gray. Apothecia linear, extending parallel to the fibres 
 of the wood. Disk dark. Spores simple, colorless, 
 ovoid, 15/x X 6.5/x. 
 
 This plant occurs upon rotten logs, and is character- 
 istic in appearance. The algae are Protococcus. 
 
 2, Xylographa opegraphilla. Thallus soon becomes 
 epiphloeodal, distinct, areolate, areoles easily removed, 
 pale-gray. Apothecia short-linear, rarely branching. 
 Disk pale-brown to dark. Spores simple, ovoid, 
 colorless, 14/x X 6yu,. 
 
 In this lichen the algae are Chroolepus. 
 
 5. Arthonia. 
 This is in many respects a difficult group for study, 
 principally because its representatives are numerous 
 
GENERA AND SPECIES. 129 
 
 and lowly organized. The difficulty is increased by 
 the fact that many species are generally sterile, that 
 is, they are without spores though apothecia may be 
 present. Tlie thallus is deficient and the algal charac- 
 ters are variable ; in some cases it is evidently Chroo- 
 lepus, in others, Protococcus. Further investigation 
 may make it advisable to subdivide the group upon 
 these algal differences. 
 
 The apothecial characters are also variable. Along 
 with the thallus, the apothecia begin their development 
 below the surface of the substratum, breaking through 
 some time before maturity ; rarely they remain cov- 
 ered over by a thin layer of the thallus and substra- 
 tum. They are small, irregular in outline, never 
 distinctly linear ; sometimes they are stellate or tend 
 to become linear, with radiating projections. The 
 disk and hypothecium are dark, sometimes reddish- 
 brown. 
 
 The spores are characteristic in form ; they are ob- 
 long, either colorless or dark-colored, usually four- 
 celled, the ends blunt, narrowed toward one end caus- 
 ing it to resemble the outline of the sole of a shoe. 
 
 The Arthonias are southern in their range, though 
 less so than Graphis. Tkey occur upon trees. 
 
 1. Arthonia astroidea. Thallus indistinct, mostly 
 hypophloeodal. Apothecia numerous, irregular, stel- 
 late, sometimes somewhat elongated ; only sliglitly 
 raised above the substratum (bark). Disk black. 
 Spores colorless, four-celled, 12/u, X 5^. 
 
 2. Arthonia dispersa. Resembling A. astroidea ; 
 the apothecia are fewer and more scattered. 
 
130 GUIDE TO THE STUDY OF LICHENS. 
 
 Species of Nostoc and Sirosiphon (S. pulvinatus) 
 occur parasitically upon many of the Arthonias. 
 
 3. Arthonia quintaria. Thallus rudimentary, partly 
 hypophloeodal, evenly spreading, light-gray. Apothe- 
 cia small, irregular to somewhat linear, scattered. 
 Spores colorless, four to seven-celled, somewhat curved, 
 narrowed toward one end, 24/u, X 7/x. 
 
 4. Arthonia tcediosa. Thallus rudimentary, partly 
 hypophloeodal, evenly spreading, extending over the 
 apothecia in the form of a thin film, light color to green- 
 ish. Apothecia medium, numerous, irregularly stel- 
 late. Disk dark. No spores came to my notice. The 
 spore-sacs were either entirely empty or contained only 
 immature, gelatinized spores. 
 
 5. Arthonia radiata. Thallus much as in A. quin- 
 taria. Apothecia more numerous, larger, irregularly 
 stellate. Spores colorless, four-celled, 17ft, X 4.0/x. 
 
 6. Arthonia punctiformis. Thallus rudimentary, 
 partly hypophloeodal, evenly spreading, light-gray. 
 Apothecia very small, irregular in form. Disk dark. 
 No mature spores came to my notice. 
 
 7. Arthonia polymorpha, Thallus partly hypoph- 
 loeodal, evenly spreading, pale color. Apothecia of 
 very irregular outline, thinly overspread by the thal- 
 lus. Disk dark-brown. No spores seen. 
 
 8. Arthonia lecidella. Thallus distinct, irregularly 
 areolate, light bluish-green ( Chroolepus and Protococ- 
 cus both present). Apothecia rounded, slightly raised. 
 Disk somewhat convex, dark. Spores as in A. as- 
 troidea. 
 
 9. Arthonia glahrata. Thallus quite distinct, some- 
 
Genera and species. 131 
 
 what areolate, grayish in color, partially enclosing the 
 apothecia. Apothecia comparatively large, irregular 
 in outline. Disk dark. Spores not seen. 
 
 10. Arthonia atra. Thallus rudimentary, mostly 
 hypophl(]eodal, light color. Apothecia numerous, 
 oblong to linear or branching. Disk dark. Spores 
 typical, 16/x X 4:.5/x. 
 
 11. Arthonia varia. Thallus rudimentary, light- 
 gray. Apothecia distinct, linear, not branching. 
 Spores typical, 15/x X 3/x. 
 
 6. Mycoporum. 
 
 This is a small group whose position is rather un- 
 certain. It is evidently closely related to the Graphid- 
 acecB. 
 
 The thallus is rudimentary and begins its develop- 
 ment below the surface of the substratum. It, how- 
 ever, soon breaks through, forming a deficient crus- 
 tose thallus. The algae are perhaps Protococcus, 
 though they also have a resemblance to Pleurococus. 
 
 The apothecia are irregular in outline but never 
 distinctly linear. Disk and hypothecium are black. 
 The spores are large, eight in number, multilocular, 
 colorless to brownish, and constricted at the middle. 
 
 The few representatives occurring in the United 
 States seem to be southern in their range, occurring 
 upon trees. 
 
 1. Mycoporum pycnocarpum. Thallus deficient, 
 evenly spreading, grayish. Apothecia small, scat- 
 tered, irregular in outline, scarcely raised above the 
 thallus and substratum. Spores large, multilocular, 
 
132 GUIDE TO THE STUDY OF LICHENS. 
 
 colorless to brown, constricted at the middle, 84/u 
 X 40^. 
 
 7. Arthothelium. 
 
 This group is usually associated with Arthonia. 
 It also resembles Mycoporum in many respects. 
 
 The thallus is rudimentary, often indistinctly areo- 
 late, grayish to dark in color. The algae are Ghroo- 
 lepus. The apothecia are comparatively large, stel- 
 late. The disk is dark. The entire thecium and 
 hypothecium may be dark ; again it is found to be 
 colorless. 
 
 The spores resemble those of Mycoporum, but dif- 
 fer in that they are colorless and not constricted at 
 the middle. Each spore-sac bears eight spores, which 
 is uncommon with lichens bearing such large spores. 
 
 The Arthothelias are southern in their range. They 
 occur upon trees, most frequently upon hickories. 
 
 1. Arthothelium spectahile. Thallus rudimentary, 
 areolate. Apothecia numerous, comparatively large, 
 irregular, stellate. Disk black. Spores large, multi- 
 locular, colorless, 78/a X 4:0/*. 
 
 V. PHYSCIACE^. 
 
 The representatives of this family are characterized 
 by the two-celled spores in which the protoplasmic con- 
 tents are joined by a slender thread, a characteristic 
 not noticeable in spores of any other lichen-group. 
 
 The thallus varies from typically crustose to foliose 
 and fruticose, and, as is natural to suppose, it is varia- 
 ble in size, though it never attains any very great 
 dimensions. The foliose forms are often mistaken 
 
GENERA AND SPECIES. 133 
 
 for species of Parmelia^ otherwise there is little dif- 
 ficulty in recognizing the Physciacece. 
 
 The apothecia belong to the thalline type, that is 
 the algaB of the thallus enter into its structure ; they 
 are discoid, rarely immersed, the disk is flattened or 
 concave, sometimes convex. 
 
 The Physciacece seem to be better adapted to re- 
 sist extremely dry periods than most lichens. They 
 are rich in deposits of lichenic acids, which cause 
 some of the characteristic colorations in thallus and 
 apothecia. 
 
 KEY TO THE GENERA. 
 
 Thallus crustose, areolate, margin often lobed. 
 
 Spores brown, thallus not bright-yellow . 1. Rinodince. 
 
 Spores colorless, thallus yellow to orange, 2. Placodium. 
 Thallus foliose, gray, not yellow. 
 
 Hypothecium dark 3. Pyxlne. 
 
 Hypothecium colorless 4. Physcia. 
 
 Thallus foliose to fruticose, often yellowish, 5. Theloschistes. 
 
 1. Rinodina. 
 
 This genus represents the lowest group of the 
 Physciacece, The thallus is typically crustose, gray 
 or greenish in most species ; in R. oreina the thallus 
 is of pale dirty lemon or sulphur color ; in R. chryso- 
 melcena there is also a marked yellowish tinge. In 
 some species a tendency toward the foliose type 
 is noticeable. Usually the thallus is distinctly 
 areolate and closely aduate to the substratum. The 
 areoles are bounded by a thin black zone which some 
 authors designate as the " hypothallus." 
 
 The apothecia are immersed or sessile. In the ses- 
 sile forms the thalloid margin extends somewhiU above 
 
134 GUIDE TO THE STUDY OF LICHENS. 
 
 the disk. In the immersed apothecia the disk is ir- 
 regular in outline. The spores are dark in the major- 
 ity of species. The algae are Protococcus (excepting 
 R. oreina). 
 
 The Rinodinas are quite common throughout the 
 United States, but have a slight western and southern 
 tendency. They occur uj^on rock and bark, less com- 
 monly upon soil and moss. 
 
 1. Rinodina constans. Thallus thin, evenly spread- 
 ing, granular to areolate, grayish-green. Apothecia 
 small to medium. Thalloid exciple slightly raised 
 above the dark disk. Spores brown, 17/x, X 8.5/x.^ 
 
 2. Rinodina Bishoffii. Thallus varies from thinly 
 granular to quite thick and indistinctly areolate, brittle, 
 closely adnate though readily removed, often leaving 
 the apothecia behind. Apothecia rather small, slightly 
 raised above the thallus. Disk flattened, black. Spores 
 dark-brown, connecting thread often indistinct, sep- 
 tum thick, 17/x X 12/A. 
 
 3. Rinodina sophodes. Thallus of rather indistinct, 
 more or less scattered, irregular areoles, grayish-green 
 above, dark beneath. Apothecia small. Thalloid 
 exciple, usually deficient. Disk black. Spores brown, 
 slightly constricted at the middle, 22/x X 8/x. 
 
 J/.. Rinodina oreina, Thallus distinctly areolate, 
 comparatively thick, lemon or sulphur color. Apothe- 
 cia immersed, small to medium. Disk black or dark- 
 brown. Spores dark-brown, connecting thread not vis- 
 ible, septum thick, somewhat constricted, 10/x X 6.5/a. 
 
 1 Other generic spore-charactera .are given in the family descrip- 
 tion, which see. 
 
GENERA AND SPECIES. 135 
 
 This lichen has been made the basis of the distinct 
 genus {Dimelcena). Its spore-characters closely re- 
 semble those of Buellia. It occurs typically upon 
 granitic rock. 
 
 5. Rinodina chrysomelcena. Thallus rather thick, 
 irregularly areolate, margin indistinctly lobulate ; yel- 
 lowish-green above, black beneath. Apothecia small, 
 margin elevated above the dark flattened disk. Spores 
 dark-brown, connecting thread distinctly visible, 25^ 
 X 11/x. 
 
 6. Rinodina turfacea. Thallus verrucose (warty), 
 more or dess branching, grayish-green. Apothecia 
 from small to medium in size, margin extending slightly 
 above the dark flattened disk. Spores brown, slightly 
 constricted at septum, 25.5/x X 12/x. 
 
 2. Placodium. 
 
 The representatives of this genus are characterized 
 by the orange coloration of the apothecial disk. The 
 thallus varies from typically crustose to distinctly foli- 
 ose, though it never attains any great size ; in color it 
 is usually yellow or orange, rarely gray to dark. The 
 yellow color is due to the deposition of crystals of 
 chrysophanic acid. 
 
 The apothecia are discoid, of medium size, sessile, 
 with a distinct thalline margin. The spores are color- 
 less, with terminal plasmic masses connected by a slen- 
 der plasmic thread. The transverse septum is not dis- 
 tinct, as in Rinodina ; rarely are the spores simple. 
 
 The distribution of the Placodias is much as that of 
 Rinodina, They occur upon rock, also upon bark, fences 
 
136 GUIDE TO THE STUDY OF LICHENS. 
 
 and old buildings. Some of the species are confused 
 with Theloschistes. 
 
 1. Placodium ferrugineum. Thallus granular and 
 indistinctly areolate, variable shades of gray. Apothe- 
 cia medium, margin scarcely raised. Disk flattened, 
 rusty-brown to black. Spores typical, 17 fx X 8.5/x. 
 
 2. Placodium cerinum. Thallus evenly spreading, 
 granular, sometimes indistinctly areolate, dark-brown. 
 Apothecia small. Disk convex, reddish-brown, margin 
 not raised. Spores typical, 12/x X 6.5/x. 
 
 3. Placodium aurantiacum. Thallus varies from 
 evenly spreading to coarsely granular and areolate, 
 greenish-yellow or lemon color. Apothecia variable 
 in size and number. Disk flattened or slightly con- 
 vex, margin somewhat raised, reddish-brown. Spores 
 typical, 17/u, X 8/m. 
 
 Jf. Placodium citrinum. Thallus of powdery (so- 
 redioid) granules, areolate, lemon color. Sterile. No 
 apothecia-bearing specimens have come to my notice. 
 The plant is usually mutualistically or antagonistically 
 associated with species of Lecanora^ and it may be that 
 the spores of the latter have been described as the 
 spores of P. citrinum. 
 
 5. Placodium cinnabarinum. Thallus areolate, are- 
 oles sometimes scattered, bright-orange. Apothecia 
 small, almost entirely immersed in the areoles. Disk 
 concave, margin slightly paler than thallus. Spores 
 typical, 9/x, X 4/a. 
 
 6. Placodium murorum. Body of thallus of convex 
 more or less irregular squamules, margin of elongated 
 bifurcate lobules, closely adnate, orange color. Apo- 
 
GENERA AND SPECIES. 137 
 
 thecia numerous, small to medium. Disk flattened or 
 slightly convex, darker orange than thallus, margin 
 scarcely raised. Spores typical, 10/x X 5/x,. 
 
 Placodium murorum has been classed by authors 
 with Lecanora as well as ParmeUa. It occurs upon 
 walls, rocks, bricks, tiles, mortar, etc. 
 
 7. Placodium elegans. Thallus distinctly foliose, 
 radial growth, forked branching, lobes of uniform 
 width, convex above, somewhat concave below, ends 
 of branches turning down ; orange above, dark-gray 
 beneath with black rhizoids. Apothecia medium to 
 large, cup-shaped. Disk orange. Spores typical, 
 10/x X 8/x. 
 
 This species as well as other species of Placodium 
 has been classed with ParmeUa. P. elegans is said 
 to occur on granitic rock on the highest mountains. It 
 has been collected on Orizaba at an elevation of 14,850 
 feet. Agassiz brought it from the summit of the Jung- 
 frau. 
 
 3. Pyxine. 
 
 Only two species of this genus occur in the United 
 States, one of which is probably not a Pyxine. P. 
 sorediata is nearly always sterile. As represented by 
 the only two species, the thallus is foliose, quite 
 large, thin and closely adnate to the substratum, branch- 
 ing quite distinct. Color of the thallus ash-gray, re- 
 sembling that of the Pkyscias, to which this group is 
 evidently closely related.^ 
 
 The apothecia are discoid. Disk dark, likewise the 
 
 1 UnlesB otherwise stated, the algsB of any lichen-genus or lichen- 
 *pecie» are Protococcus (Cystococcus humicola of Nageli). 
 
138 GUIDE TO THE STUDY OF LICHENS. 
 
 hypothecium, which characterizes the genus. The spores 
 are two-celled, the cells united by a plasmic thread, 
 dark-brown. 
 
 1. Pyxine picta. Thallus thin, membranaceous, 
 closely adnate to the substratum, indistinctly lobed 
 toward the margin, older portion of the thallus more 
 or less warty. Apothecia of medium size, discoid, ses- 
 sile. Disk dark to black, flattened. Spores dark- 
 brown, typical of the family, 18/x X 7/x. 
 
 2. Pyxine sorediata. Thallus much branched, lobed, 
 long and of uniform width, grayish-green above, black, 
 with numerous rhizoids, below ; numerous soralia occur 
 along the upper margins of the lobes. Apothecia very 
 rare. Disk flattened or convex, dark. Spores dark- 
 brown, typical, 17/x X 7/x. 
 
 This lichen requires further careful study. It is 
 perhaps not a Pyxine. Only scant and unsatisfactory 
 apothecia-bearing material has come to my notice. It 
 has been described as Pyxine cocoes^ Parmelia sore- 
 diata, Pyxine cocoes variety sorediata, as a Physcia, 
 
 etc. 
 
 4. Physcia, 
 
 The thallus is almost crustose in a few of the lower 
 species ; otherwise it is typically foliose, much-branched 
 and extending flatly over the substratum. The color 
 is usually gray tinged with green above, with a differ- 
 ent color beneath, usually lighter, rarely dark to black, 
 much of the dark coloration being due to rhizoids. In 
 some species the margin of the thallus-lobes are lined 
 with dark cilia. Whitish soralia are also common upon 
 the thalli of many species. 
 
GENERA AND SPECIES. 139 
 
 The apotliecin belong to the tlialline type, and are 
 discoid, sessile, small to medium in size. The disk is 
 dark in color. There is no yellow or orange colora- 
 tion in this genus. It may also be mentioned that 
 spermagonia occur upon many species. The spores 
 are typical of the family, closely resembling those of 
 Rinodina. 
 
 The Physcias have a wide range ; the higher forms 
 are somewhat southern. They occur upon bark and 
 rock. 
 
 Formerly the PJiyscias were quite generally com- 
 bined with Parmelia, from which group they are, how- 
 ever, readily distinguished by the spore-characters and 
 by the differences in the appearance of the thallus. 
 
 1. Physcia adglutinata. Thallus crustose, thin, 
 very closely adnate to the substratum, central portion 
 areolate, warty, margin lobed, lobes of uniform width ; 
 dark colored. Apothecia small to medium. Disk dark- 
 brown, margin slightly crenulate. Spores brown, 
 typical, 15/x X 8.. 5 /a. 
 
 2. Physcia obscura. Thallus comparatively small, 
 branching, firmly attached to the substratum, green- 
 ish-gray above, black beneath, with numerous rhizoids. 
 Apothecia small to medium, margin extending above 
 the dark-brown disk. Spores brown, typical, 24/x 
 X 10.5/x. 
 
 3. Physcia setosa. Thallus much as in P. obscura, 
 lobes broader, often bearing soredia, black below, with 
 densely crowded black rhizoids. Apothecia rare; none 
 have come to my notice. 
 
 4. Physcia ccesia. Thallus comparatively small to 
 
140 GUIDE TO THE STUDY OF LICHENS. 
 
 medium, branching; lobes linear, slender, pale-gray 
 above, with darker soralia, slightly darker beneath, 
 with rigid rhizoids. Apothecia not seen. 
 
 5. Physcia tribacea. Thallus rather small, minutely 
 branched, lobes not uniform in size, crenulate, greenish- 
 gray above, light color beneath, rhizoids few. Apothe- 
 cia small to medium, margin entire. Disk dark-brown 
 to black. Spores brown, oblong, ovoid, 17/x X 8/x. 
 
 6. Physcia stellaris. Thallus rather small, branched, 
 lobes of uniform width, lying flat upon the substratum, 
 ash-gray to brown above, light-brown beneath, rhizoids 
 comparatively few. Apothecia as in P. tribacea. 
 Spores brown, typical, 19/x X 10.0/>t. 
 
 7. Physcia pulverulenta. Thallus large, branched, 
 lobes variable from linear to broad, brittle, sometimes 
 bearing minute conical or strap-shaped outgrowths ; 
 light-gray to brown, overspread by a translucent white 
 coloration. Apothecia medium to large, margin slightly 
 elevated and bearing conical or warty outgrowths. Disk 
 dark-brown, with a translucent white coloration. Spores 
 dark-brown, constricted in the middle, connecting thread 
 not distinct, 32.5/x X 17/x. 
 
 8. Physcia aquila. Thallus large, much branched, 
 lobes linear, gray to brown above, nearly the same 
 color below with large dark rhizoids, older parts of 
 thallus and apothecia bearing numerous conical out- 
 growths or small thalloid lobules. Apothecia medium, 
 margin often isidioid. Disk dark-brown. Spores 
 large, brown, 29.0/x X 18.0/x. 
 
 9. Physcia hyjjoleuca. Thallus large, branched, ad- 
 herent to the substratum, ash-gray above, pale beneath, 
 
GENERA AND SPECIES. 141 
 
 rhizoids sparingly present and black. Apothecia nu- 
 naerous, medium to large, cup-shaped, margin incurved, 
 crenate. Disk dark-brown. Spores brown, typical, 
 36/x, X 17/x. 
 
 10. Physcia speciosa. Thallus branched, lobes strap- 
 shaped, bearing a few cilia, usually lying close, but 
 only loosely attached to the substratum, greenish-gray 
 above, lighter color beneath with comparatively few 
 dark rhizoids. Apothecia medium to large, cup-shaped, 
 crenulate margin curved inward. Spores brown, 
 typical, 21/x X Hfi* 
 
 11. Physcia comosa. Thallus branched from two 
 to about six times, lobes ascending and of quite uni- 
 form width ; numerous, long, slender, dark cilia from 
 the margin, rarely from the upper surface of the thal- 
 lus as well ; uniform, pale ash-gray above, paler below, 
 no rhizoids. Apothecia terminal, margin extending 
 considerably above the gray disk. Spores brown, 
 11 fx X 34/.. 
 
 12. Physcia hispida. Thallus much as in P. co- 
 mosa but with lobes inflated at the tips, cilia usually 
 more slender and numerous. Apothecia medium, mar- 
 gin only slightly raised above disk. Disk gray to 
 nearly black. Spores brown, 20.5/i, X ll/>t- 
 
 13. Physcia ciUaris. Thallus much branched, lobes 
 linear, somewhat ascending, branches terminating in 
 long slender cilia, which are usually darker than the 
 lobes; ash-colored to dark-brown above, nearly the 
 same color beneath, no rhizoids. Apothecia rare, me- 
 dium, cup-shaped, bearing some short cilia. Disk 
 brown to dark. Spores dark-brown, 35/x X 17/a. 
 
142 GUIDE TO THE STUDY OF LICHENS. 
 
 5. Theloschistes. 
 
 The thallus varies from almost foliose to fruticose. 
 The fruticose forms are much branched and usually 
 bear long grayish cilia along the margin of the lobes. 
 Usually there is more or less of a yellowish tinge ; in 
 some only a grayish color. Soralia are less common 
 than in Physcia. 
 
 The apothecia are discoid, usually larger than in 
 Physcia. Disk orange, yellowish, in some species dark- 
 gray to nearly black. The spores resemble those of 
 Placodium, from which this group is perhaps pliylo- 
 genetically derived. 
 
 The Theloschistes are more southern and western 
 than the Physcias. They occur upon bark, rock, old 
 walls, fences, old buildings, etc. Frequently they are 
 associated with species of Physcia. 
 
 1. Theloschistes polycarpus. Thallus foliose, lobe 
 short, rounded, dirty lemon to orange. Apothecia 
 usually small, very numerous, the entire margin of 
 the thallus studed with them. Disk concave, orange. 
 Spores colorless, typical, 15^ X 8/a. 
 
 2. Theloschistes lychneus. Thallus foliose, branch- 
 ing, lobes broad and more or less ascending, soralia 
 often present; orange above, lighter color beneath. 
 Apothecia rare, medium size. Disk flattened, red- 
 dish-brown. Spores colorless, typical, 12/x X 8.5/x. 
 
 3. Theloschistes concolor. Thallus foliose, minutely 
 branching, lobes of uniform width, not ascending, 
 greenish-yellow above, gray beneath. Apothecia of 
 medium size, cup-shaped, margin somewhat fibrillose. 
 Disk of the same color as thallus. The spores are 
 
GENERA AND SPECIES. 143 
 
 Bmall, colorless and cells not distinctly terminal, 
 8.5/x X V 
 
 Jf. T/ieloschistes parietinus. Thallus always dis- 
 tinctly foliose, but varial)le in the development of the 
 lobes ; lobes usually short and rounded and somewhat 
 upturned at the margin, pale-lemon to reddish-brown. 
 Apothecia from medium to large. Disk orange. 
 Spores colorless, typical, \2^x X 7/x. 
 
 This lichen has quite generally been classified as 
 ParmeUa parietina ; also as Physica parietina. An 
 older name, Candelaria^ was derived from the fact that 
 the lichen was used by the Swedes to give a yellow color 
 to candles used in religious ceremonies. In England it 
 has been extensively used to color Easter eggs. This 
 is the lichen which was recommended as a substitute 
 for quinine (1815). It was also highly recommended as 
 an astringent in hemorrhages and as a febrifuge. It 
 occurs in London drug-shops as " Common yellow 
 Wall-moss," being probably chiefly utilized by the 
 taxidermist. It is southern in its range. 
 
 5. Thelosckistes chrysophthahnus. Thallus fruticose, 
 branching, lobes flat, terminating in rigid cilia ; yel- 
 lowish-orange above, grayish beneath. Apothecia 
 usually terminal, medium to large, margin usually 
 ciliate. Disk orange. Spores colorless, typical, 14/oi 
 X 7.5;a. 
 
 This is a beautiful plant, growing in tufts upon 
 trees. 
 
 6. Tltcloschistes Jiavicans. Thallus fruticose, much 
 branched, pendant, soralia often present, ciliate ; yel- 
 lowish-gray to reddish-brown. Apothecia medium to 
 
144 GUIDE TO THE STUDY OF LICHENS. 
 
 large, lateral or terminal. Disk reddish-brown. Spores 
 colorless, typical, 16/w, X 7.5/i. 
 
 7. Theloschistes leucomela. Thallus fruticose, much 
 branched, lobes uniform, flat, long, ciliate ; gray above, 
 lighter beneath. Apothecia large, margin ciliate. 
 Disk dark-gray. Spores light-brown, large, 51/x X 
 
 This is a southern species and a very handsome 
 plant. Fine specimens from Lower California have 
 come to my notice. It would have been perhaps more 
 correct to classify this lichen with Physcia, in accord- 
 ance with Lindsay and others. 
 
 VI. PARMELIACEyE.^ 
 
 In this family the thallus varies from typically 
 crustose to typically foliose and fruticose. In all 
 forms above the crustose types the thallus is much 
 branched. The apothecia belong to the thalline type ; 
 they are discoid, and attain their maximum size in 
 such genera as Usnea, Parmelia and Peltigera. 
 
 The position and limitation of the family are depend- 
 ent upon the following characters: 1. The absence 
 of stipes and podetia excludes it from the Caliciacece 
 and CladoniacecE. 2. The presence of the thalline 
 apothecia excludes it from the Lecidiacece. 3. The non- 
 union of the spore-cells excludes it from the Physciacece. 
 4. Presence of discoid sessile apothecia separates it 
 from the Graphidacece and Verrucariaceoe. 5. The 
 
 1 In the study of most of the genera of this family I received speci- 
 mens from the collection of my friend W. W. Calkins, for the use of 
 which I express my sincere gratitude. 
 
GENERA AND SPECIES. 145 
 
 absence of blue-green algje ( CyanophycecB) finally 
 separates it from the Collemacece and Pannariacece. 
 
 KEY TO THE GENERA. 
 
 Thallus crustose and areolate to thickly 
 warty and minutely foliosc. 
 Spores not simple. 
 
 Multilocular, dark 1. Urceolaria. 
 
 Five to seven-celled, acicular, color- 
 less 2, Hiematomma. 
 
 Spores simple, colorless. 
 
 Usual size and number (8) .... 5. Lecanora. 
 Very minute and numerous (200) . 4- Acarospora. 
 Thallus foliose, lobed or branching, spores colorless. 
 
 Spores two-celled <5. Speerschneidera. 
 
 Spores simple. 
 
 Thallus greenish, lobes never erect . 6. Pannelia. 
 Thallus brownish, lobes sometimes 
 
 erect 7. Cetraria. 
 
 Thallus fruticose. 
 
 Lobes distinctly flattened, spores colorless. 
 
 Spores two-celled 8. Ramalina. 
 
 Spores simple 9. Rocella. 
 
 Lobes not distinctly flattened, yellow- 
 ish 10. Evernia. 
 
 Lobes cylindrical, filamentous and 
 very long, spores simple. 
 Central hyp ha I core wanting. 
 
 Thick exosporium 11- Alectoria. 
 
 Normal exosporium 12. Bryopogon. 
 
 Central hyphal cores present . . .13. Usnea. 
 
 1. Urceolaria. 
 
 Thallus crustose, usually quite thick and areolate, 
 the areoles becoming distinctly convex or warty in 
 some species. Tlie prevailing color of the upper sur- 
 face is gray, lower surface whitish. The algaj are 
 no doubt Protococcus ; they usually occur in groups 
 of six to twelve, tlius differing from the usual forms 
 which occur singly. 
 
146 GUIDE TO THE STUDY OF LICHENS. 
 
 The apothecia are quite small, globose, and are 
 immersed in the thallus, opening by a pore. The 
 hypothecium is usually dark. The genus should 
 perhaps be placed with the VerriicariacecE, since 
 its apothecial characters point toward such a relation- 
 ship. 
 
 The spores, when mature, are multilocular and 
 dark. The immature spores are simple, colorless, and 
 larger than the mature spores. It should also be 
 borne in mind that the mature spores are often quite 
 structureless. 
 
 Most of the species are northern in their range. 
 They occur upon rocks, a few upon the soil. 
 
 1. Urceolaria actinostoma. Thallus comparatively 
 thin, areola te, areoles never convex ; gray to dark-gray. 
 Apothecia small, immersed in somewhat convex areoles. 
 Disk dark. Spores dark, multilocular, 14)u, X 7.5/x. 
 
 2. Urceolaria scruposa. Thallus quite thick, areo- 
 late, fissured, gray. Apothecia immersed in somewhat 
 elevated areoles. Disk somewhat darker than thallus. 
 Spores dark-brown, elliptical, multilocular, 21/jt X 9/a. 
 
 An orange coloring substance is obtained from the 
 Urceolarias ; it was used in dyeing woollen goods. 
 
 2. Hcematomma. 
 
 This genus is usually combined with Lecanora, 
 though its spore-characters are wholly different. The 
 thallus is crustose but very thick; sometimes covered 
 over by a soredial powder. The color is gray tinged 
 with green, or sometimes yellowish. 
 
 The apothecia vary from medium to quite large; 
 
GENERA AND SPECIES. 147 
 
 they are usually discoid, irregular in outline, sessile or 
 adnate upon the thallus. The disk is usually flattened, 
 margin only slightly elevated. Hypothecium is color- 
 less. 
 
 The spores are long, acicular, pointed toward one 
 end, curved, undulate or twisted, colorless, five to 
 seven-celled. The spores are very characteristic, and 
 when once seen are not likely to be mistaken ; they re- 
 semble most nearly those of Bacidia. 
 
 I'he species occur upon rock, trees, earth, logs, etc. 
 They are somewhat northern in their range and prefer 
 mountainous districts. 
 
 1. HcBmatomma punicea. Thallus areolate to warty, 
 greenish-gray. Apotliecia small. Disk bright reddish- 
 brown. Spores acicular, colorless, five'to seven-celled, 
 
 2. Hcematomma ochrophcea. Thallus thick, warty, 
 not fissured, grayish-green, white internally. Apothecia 
 small to medium. Disk pale to dark brown. Spores 
 colorless, indistinctly five to seven-celled, curved, 
 49/x X 4.5/x. 
 
 S. Hcematomma ventosa. Thallus very thick, deeply 
 fissured; surface areolate, warty; yellowish-green to 
 dirty green above, white within and beneath. Apothecia 
 medium to large, spreading, margin irregular in out- 
 line and somewhat lobulate. Disk reddish-brown. 
 Spores five to seven-celled, colorless, curved, thinner 
 toward one end, 37/x X 2/x.. 
 
 The so-called L^'Cidea parasitica (perhaps a fungus) 
 is often parasitic upon this plant. H. ventosa is closely 
 related to the foreign Lecanora esculenta already men- 
 
148 GUIDE TO THE STUDY OF LICHENS. 
 
 tioned in the historical review. The HcBmatommas 
 have also found a place in the dyeing industries. 
 
 3. Lecanora. 
 
 The thallus varies from crustose to somewhat foliose. 
 It is highly probable that the Parmelias are the 
 direct descendants of the Lecanoras. The amateur is 
 likely to confuse the Lecanoras and Biatoras^ since 
 they resemble each other in their general characters, 
 especially the spore-characters. The foliose forms 
 have numerous small, more or less jjlicate, lobes which 
 are somewhat ascending and bear numerous rhizoids. 
 Color of the thallus varies from light-green to dark. 
 
 The apothecia are generally plentiful; as compared 
 with the apothecia of the Biatoras they are quite large. 
 They are discoid, sessile, not immersed ; margin ex- 
 tending somewhat above the brown to nearly black 
 disk. Hypothecium colorless. 
 
 The spores are simple, colorless, elliptical, some- 
 what variable in size and form. 
 
 The Lecanoras occur upon bark and rock and have 
 a wide range. 
 
 1. Lecanora lacustris. Thallus very thin, uniformly 
 spreading, indistinctly areolate ; reddish-brown. Apo- 
 thecia small, scattering, partially immersed, margin 
 somewhat raised. Disk reddish-brown to dark. Spores 
 rarely mature. 
 
 2. Lecanora orosthea. Thallus thin, powdery to 
 finely granular, pale sulphur color. Apothecia of 
 medium size, margin barely raised, somewhat crenate. 
 Disk pale-brown. Spores ovoid, colorless, 14/* X 7.5/i. 
 
•LATK L/. Cnistosc Tyiu's. Vn 
 Y. (Mark in ilic li.Tl.iiriimi of tlic 
 Science, Lccduora jKillida. 
 
 ifon 
 
 nllf.'tinli nf X . 
 
 ia Ai'adeiiiN nf 
 
GENERA AND SPECIES. 149 
 
 S. Lecanora Bockii. Thallus granular, somewhat 
 areolate ; dark. Apothecia small, slightly raised above 
 thalhis. Disk somewhat lighter in color than thallus. 
 Spores rare, typical. 
 
 4. Lecanora calcarea. Thallus areolate, dark. 
 Apothecia small, usually numerous, irregular, margin 
 slightly raised above the brown to dark-brown disk. 
 Spores elongated, slightly curved, 15.5^ X 4/x,. 
 
 5. Lecanora Hageni. Thallus granular to indis- 
 tinctly warty, gray to dark. Apothecia small, numer- 
 ous ; margin entire, elevated ; light-gray. Disk reddish- 
 brown to dark-brown. Spores ovoid or elliptical, 7.5/x 
 X 4.5/x. 
 
 Nos. 4 and 5 are generally associated with species 
 of Placodium. 
 
 6. Lecanora pallida. Thallus uniform, areolate, 
 rarely granular and warty, pale color. Apothecia 
 medium to large, somewhat lobulate or folded, elevated 
 margin. Disk flattened, pale-brown to brown. Spores 
 typical, 12/i, X 6/u,. 
 
 7. Lecanora Cupressi. Thallus granular to warty, 
 pale-green. Apothecia small to medium, numerous, 
 margin crenulate. Disk pale yellowish-brown. Spores 
 typical, slightly curved, 13/w, X 4.5/x. 
 
 8. Lecanora varia. Thallus much as in L. 
 Cupressi, more distinctly warty. Apothecia as in 
 No. 7, margin more elevated ; spores the same. 
 
 Nos. 7 and 8 are evidently closely related, if not 
 identical. L. varia is quite common and has a wide 
 range. Saussure and Agassiz collected specimens on 
 the summits of the Alps. 
 
150 GUIDE TO THE STUDY OF LICHENS. 
 
 9. Lecanora suhfusca. Thallus rudimentary to 
 warty or areolate, light-gray to light-brown. Apo- 
 thecia small to medium, margin entire and some- 
 what flexed, slightly elevated. Disk flattened to 
 convex, reddish-brown to black. Spores typical, 
 9/x X 6/t. 
 
 It is perhaps likely that most authors combine several 
 species in the above. It is of common occurrence and 
 has a wide range. 
 
 10. Lecanora atra. Thallus evenly spreading, be- 
 coming warty and areolate, gray. Apothecia medium, 
 margin slightly raised above the flattened black disk. 
 Spores typical, 12/x X 6/x. 
 
 This lichen has been used in dyeing. 
 
 11. Lecanora pallescens. Thallus rather thin, 
 more or less ridged or chinky, according to the 
 nature of the substratum (bark), surface smooth ; 
 pale-gray. Apothecia medium to large, margin some- 
 what rugose. Disk pale-brown. Spores large, typical, 
 SQfi, X 21/*. 
 
 " This lichen yielded the * Orseille d'Auvergne.' 
 The pigment was prepared chiefly at St. Flour and 
 Limoges, and the lichen was collected by the peasantry 
 of Auvergne, Limousin, Languedoc, Provence, Lyons 
 and other districts of southern France. Manufacturers 
 distinguished two varieties, white and gray, depend- 
 ing chiefly on the maturity and purity of the plant, 
 the latter being preferred. Under the name of ' Light 
 Crottle ' it has been much used by the Scotch High- 
 landers to yield an orange or reddish dye for woollen 
 goods ; and as the common ' Crab's-eye Lichen * it 
 
GEJfKRA AND SPECIES. 151 
 
 appears to have been gathered in the North of Eng- 
 land." — Lindsay. 
 
 12. Lecanora cenisia. Thallus thick and readily 
 removed from substratum (rock), consisting of large 
 confluent warts, light-gray. Apothecia medium to 
 large, attached by a narrow neck ; crenate, mar- 
 gin elevated above the dark disk. Spores typical, 
 12/. X 8/01. 
 
 13. Lecanora muralis. Thallus lobed at the mar- 
 gin, areolate toward the interior, sometimes of scat- 
 tered entire lobes. Apothecia small. Disk somo.what 
 convex, brown. Spores typical, 10.5/a X 5/x. 
 
 IJf.. Lecanora tartar ea. Thallus thick, of imbricate 
 ascending branches, sometimes becoming semi-foliose 
 or semi-fruticose, light-gray to grayish-green. Apo- 
 thecia medium to large, margin somewhat rugose. 
 Disk brown to reddish-brown. Spores large, typical, 
 52/>i X 21/a. 
 
 This lichen was employed to make litmus and to 
 produce a purple for dyeing woollen goods and nowhere, 
 perhaps, used more extensively than in England. The 
 lichen was sold at about eighty cents per stone of 
 twenty-two pounds. The same rocks were scraped 
 once every five years. 
 
 15. Lecanora ruhina. Thallus-lobes ascending show- 
 ing a fruticose tendency, grayish-green above and 
 toward the apex, brown and dark below and toward 
 the basq. Apothecia medium to large ; margin cre- 
 nate and raised somewhat above the pale yellowish- 
 brown disk. Spores tyj^ical, 7.5/a X -i.O/x. 
 
152 GUIDE TO THE STUDY OF LtCHENS. 
 
 Jf.. Acarospora. 
 
 This genus is by some authors placed with Lecanora. 
 The thallus is crustose and rudimentary in the lower 
 forms ; in the higher forms it becomes foliose and 
 lobed, especially toward the margin. In many re- 
 spects the thallus resembles that of Hcematomma. 
 Color dark in the lower forms and yellowish in some 
 of the higher forms. Algas are Pleurococcus vulgaris 
 as in Endocarpon. 
 
 The apothecia are immersed in the thallus, variable 
 in size and form. The disk varies from orbicular to 
 irregularly lobate or. crenate ; it is usually flattened, 
 more rarely convex, or margin slightly elevated. 
 Color of disk varies from dark to yellowish. The 
 spore-sacs are cylindrical, and each one contains sev- 
 eral hundred very minute simple colorless spores 
 which are held together by a gelatinous substance, 
 so that the entire contents may be ejected or forced 
 out. 
 
 The Acarospora are quite widely distributed and 
 occur principally upon rock (granite) and sandy soil. 
 
 1. Acarospora privigna. Thallus rudimentary, yel- 
 lowish to dark. Apothecia small, orbicular, scattered ; 
 margin slightly elevated above the dark flat disk. 
 Spores elliptical, typical, 3/a X l-^i^- 
 
 2. Acarospora cervina. Thallus areola te, dark to 
 nearly black. Apothecia barely raised above the 
 thallus, often remaining after the thallus is worn 
 away, irregular in outline. Disk dark. Spores 
 closely adherent owing to a gelatinous substance, 
 typical. 
 
GENERA AND SPECIES. 153 
 
 This plant is often found associated with species of 
 Placodium. 
 
 3. Acarospora dealbata. Thalhis of white scattered 
 warts of considerable .thickness. Apothecia immersed, 
 one in each areole. Disk black. Spores typical. 
 
 5. Speer Schneider a. 
 
 This genus, as represented by the single species, is 
 closely related to Parmelia. The thallus is foliose, much 
 branched, with lobes of uniform width. There is also 
 a slight fruticose tendency. The apothecia are rather 
 small, sessile upon the upper surface of the thallus. 
 Disk light-brown. The spores are small, colorless, 
 elliptical and distinctly two-celled. 
 
 1. Speerschneidera euploca. Thallus much branched, 
 lobes slender, of uniform width and somewhat ascend- 
 ing, gray. Apothecia cup-shaped, sessile. Disk light- 
 brown. Spores typical. 
 
 This is the only species reported from the United 
 States, it is southern in its range. The specimens 
 which came to my notice were associated with species 
 of Collema. It is a small plant, but has a very char- 
 acteristic appearance. 
 
 6. Parmelia. 
 
 It is highly probable that this genus is phylogeneti- 
 cally derived from Lecanora^ as seems evident from a 
 comparison of the higher Lecanoras and the lower 
 ParmeJias. The exact relationship of the Hcematom- 
 mas, Acarosporas and Sj^eerschneidera is not known. 
 
 The thallus of the Parmelias is foliose, large, dis- 
 tinctly branched and lobed. It is held to tlie substra- 
 
154 GUIDE TO THE STUDY OF LICHENS. 
 
 turn by black rhizoids. White or light colored soralia 
 occur in a number of the species. As compared with 
 the Physcias the thallus is larger and less distinctly 
 ash-gray, The color varies from gray and brown 
 tinged with green and bluish-green to brown and dark. 
 
 The apothecia are distinctly cup-shaped and vary 
 from medium to very large. It shows perhaps the 
 highest development of the thalline type. It is in 
 reality a secondary thallus having a combined radial 
 and centric structure. The disk is generally brown. 
 
 The spores are simple, colorless, elliptical, often 
 bearing oil-globules ; the spore-wall is thin. 
 
 The Parmelias are common everywhere, occurring 
 upon trees, rocks, stone walls, fences, roofs of old 
 buildings, etc. Some acquire considerable dimensions, 
 reaching three or four feet in diameter. In many cases 
 there is continued marginal growth while the central 
 portion dies away, thus producing a semblance to the 
 "fairy rings" of toad-stools. 
 
 1. Parmelia conspersa. Thallus quite large, growth 
 radial, branched with lobes imbricate (overlapping) ; 
 upper surface usually smooth, sometimes bearing warty 
 outgrowths, soralia rare, brownish to greenish ; lower 
 surface brown with numerous rhizoids. Apothecia 
 small to medium, margin entire. Disk olive-brown. 
 Spores typical, 13/x X Siw- 
 
 2. Parmelia multisporum n. sp. Thallus of medium 
 size, lobed, adnate to substratum ; upper surface smooth 
 and olive color. Apothecia numerous. Disk olive to 
 chestnut-brown; thecae bearing from 50 to 100 color- 
 less elliptical spores, 5/x, X 4/a. 
 
GENERA AND SPFX'IF.S. 155 
 
 This species may be identical with P. tceniata^ though 
 it differs somewhat in the characteis of the thallus. 
 In the latter the spores are also more numerous (100 
 or more) and smaller (2.5/x X !/-«■)• So far as could 
 be determined P. multisporuin is a western species, oc- 
 curring in Washington, Idaho and Utah. The mate- 
 rial which came to notice was labelled P. olivacea, 
 which has the same general characters but bears only 
 the usual number of spores in each spore-sac (8). 
 
 3. Parmelia caperata. Thallus from medium to 
 large, of typical radial growth, branching, lobes 
 rounded, more or less crenulate, and margins turned 
 slightly upward ; upper surface rugosely folded, bluish- 
 green, soralia upon the ridges of the folds ; lower 
 surface black, brown near margin. Apothecia few 
 or wanting, medium size, margin often covered 
 with soralia. Disk chestnut-brown. Spores typical, 
 25/x X 12/x,. 
 
 In the north of Ireland and on the Isle of Man this 
 lichen is known as " Stone Crottles," and was exten- 
 sively used by the peasantry for dyeing woollen fabrics 
 a lemon color. The lichen has a wide range, occur- 
 ring throughout the United States, South America, 
 Europe and other countries. 
 
 ^. Parmelia physodes. Thallus medium to large, 
 much branched, lobes linear and somewhat ascending ; 
 tips inflated, upper surface generally bearing numerous 
 spermagonia, soralia sometimes present, brownish to 
 ash-gray ; lower surface black, brownish towanl tips. 
 Apothecia usually present. Disk chest nut-brown. 
 Spores small, typical, G/x X 4.5/x. 
 
156 GUIDE TO THE STUDY OF LICHENS. 
 
 This species is the " dark crottle " of the Scottish 
 peasantry by whom it was used to dye woollen stuffs 
 brown. It was also used as an article of diet and in 
 the manufacture of a gum similar to gum-ar?bic. 
 
 5. Parmelia saxatilis. Thallus medium to large, 
 lobes narrowed, terminal ones small ; upper surface 
 smooth, reticulately rugose, sometimes brownish, warty 
 (isidioid) outgrowths covering entire thallus, greenish- 
 gray ; lower surface black, with numerous black rhiz- 
 oids. Apothecia medium, sometimes wanting. Disk 
 brown. Spores typical, 11/x. X 9/x. 
 
 This is the "Steu-laf" of Sweden and Norway, 
 where it was used to dye thread, yarn, etc., a brown or 
 reddish-brown color. In Scotland it is one of the 
 most common " crottles " and is also known as " Stane- 
 raw " or " Staney-rag." Not only do the peasantry 
 use it but it would appear upon the evidence of the 
 border ballads that the border fairies were dressed in 
 tunics dyed with this lichen. 
 
 " Like the feld-elfin of the Saxons, the usual dress 
 of the fairies is green ; though on the moors they have 
 been sometimes observed in heath-brown, or in weeds 
 dyed with ' Stane-raw ' or ' lichen.' This lichen was 
 also used in medicine as an astringent; by the ancients 
 it appears to have enjoyed a celebrity as a sovereign 
 remedy for epilepsy and the plague." — Lindsay. 
 
 6. Parmelia Borreri. Thallus large, lobes rounded, 
 with crenulate margin, bearing a few black cilia ; upper 
 surface bearing numerous warty (isidioid) outgrowths, 
 bluish-green color, no soralia ; lower surface light- 
 brown to whitish with black rhizoids. Apothecia 
 
I'LA'l'K III. Foliosc Typrs, tliallus divitltMl. F1..111 Mt. 
 'rmiKilpais. I, I'tiniu'lid iterlata. '2. /'annelid jifii/sodes. 
 While the latter is classed as luliose, il shows a decided 
 fniticose teiideiiey. 
 
GENERA AND SPECIES. 157 
 
 few or none. Disk brown. Spores few, typical, 
 11/x X 8.5/x. 
 
 7. Parmelia perforata. Thallus large, lobes large, 
 rounded, margin somewhat crenulate, few or no soralia, 
 grayish-green, spermagonia usually numerous ; lower 
 surface black, with long black rhizoids. Apothecia 
 large, bottom of cup perforate. Disk brown. Spores 
 typical, 17/x X 10/a, 
 
 8. Parmelia latissima. Thallus large, rounded lobes, 
 with crenate margin, and bearing white soralia, light- 
 green or grayish-green above ; lower surface black, 
 becoming brown toward margin. Apothecia rare or 
 wanting. Disk brown. Spores typical, 23.5/x X 9.5/x. 
 
 This is evidently a tropical lichen. It is often con- 
 fused with the following species. 
 
 9. Parmelia perlata. Thallus large, lobes rounded, 
 crenate, bearing white soralia, grayish-green ; lower 
 surface as in P. latissima. Apothecia usually want- 
 ing. Spores typical, 13/x X 9.0/x. 
 
 This lichen yields a fine orchill. It was at one 
 time imported into England from the Canary Islands 
 as "Canary rock-moss." 
 
 7. Cetraria. 
 
 This genus is perhaps phylogenetically derived from 
 some Parmelioid type or types. The thallus varies 
 from foliose to typically fruticose, but in all cases the 
 lobes are flattened and broad. The amateur will no 
 doubt confound some species with Parmelia. In 
 general, however, the thallus is more brittle and dif- 
 ferent in color ; brown predominating. In some 
 
158 GUIDE TO THE STUDY OF LICHENS. 
 
 species there is a yellow coloration. Cilia are fre- 
 quently present; soralia are comparatively rare. 
 
 The apothecia are of medium size, discoid, usually 
 less markedly cup-shaped than in Parmelia. Disk 
 chestnut-brown, shining, margin somewhat crenate 
 or torn. The spores are simple, elliptical and color- 
 less, somewhat smaller than in Parmelia, 
 
 Most of the Cetrarias are northern, occurring upon 
 trees and rocks. 
 
 1. Cetraria Fahlunensis. Thallus foliose, much 
 branched, smooth, somewhat ascending, marginal lobes 
 olive-brown to nearly black above ; dark beneath 
 with numerous rhizoids. Apothecia few, medium to 
 large, thin. Disk chestnut-brown, smooth. Spores 
 typical, 8/x X 6.5/x. 
 
 This lichen furnishes a red (vermilion) dye. 
 
 2. Cetraria ciliaris. Thallus foliose and much 
 branched, lobes somewhat ascending and cilia te, 
 smooth ; ash-gray tinged with bluish-green above, 
 light-brown beneath, rhizoids few. Apothecia medium 
 to large, margin crenulate or torn. Disk chestnut- 
 brown, smooth. Spores typical, spherical, 6/x. 
 
 3. Cetraria juniperina. Thallus foliose, medium 
 size, branched, terminal lobes ascending, lacerate ; 
 straw color on both surfaces. Apothecia of medium 
 size, margin crenate. Disk chestnut-brown. Spores 
 typical, S/x X 6.5/x. 
 
 Upon boiling in water this lichen yields a yellow 
 coloring-matter which was much used in Sweden for 
 dyeing home-made cloth fabrics and Easter eggs. With 
 Placodium murorum it was at one time highly rec- 
 
GENERA AND SPECIES. 159 
 
 ommended for the cure of jaundice (according to the 
 similia similihus curantur principle of homeopaths). 
 
 4. Cetraria lacunosa. Thallus foliose, rather large, 
 upper surface reticulate, bluish-green tinged with 
 gray ; lower surface brownish. Apothecia medium. 
 Disk chestnut-brown, base sometimes perforate, as in 
 Parmelia perforata. Spores typical, 7.5;u, X 5./);tx. 
 
 Tiiis species is often confounded with C. ciliaris. 
 
 5. Cetraria cucullata. Thallus fruticose, terminal 
 lobes rather finely divided ; straw color, darker toward 
 base. Apothecia large, attached to che lower surface 
 of turned terminal lobes. Disk chestnut-brown. Spores 
 typical, 9.5/x X 5.5/x. 
 
 6. Cetraria Islandica. Thallus fruticose, lobes 
 comparatively narrow, rolled, rigid, erect; margin 
 lined with rigid cilia ; upper surface chestnut-brown, 
 lower surface somewhat lighter. Apothecia medium. 
 Disk chestnut-brown. Spores typical. 
 
 This lichen, commonly known as " Iceland moss," 
 has enjoyed great popularity as a medicinal substance 
 and as an article of diet. It is still extensively used as 
 food for convalescents and those having weak stomachs. 
 Icelanders powder it and use it as flour. In Scandi- 
 navia it is used as fodder for cattle. It yields a 
 brown color which was once much used for dyeing 
 woollen goods. 
 
 According to the United States Dispensatory, Ice- 
 land moss is demulcent, nutritious and tonic, well cal- 
 culated for affections of the mucous membranes of the 
 lungs and bowels in which the local disease is asso- 
 ciated with debility of the digestive organs, or the 
 
160 GUIDE TO THE STUDY OF LICHENS. 
 
 general system. The plant has, however, no active 
 curative property, and is fast going into disuse as a 
 medicine. 
 
 8. Ramalina. 
 
 In this genus the thallus is typically fruticose, the 
 lobes being flattened. In the majority of species the 
 surface is smooth. The length of the thallus varies 
 greatly ; in the smallest species an inch or less to 
 several feet in the largest. The branches are strap- 
 shaped, and in a few species tend to become cylin- 
 drical. Color varies from greenish to gray or even 
 brown. Large soralia occur on some species. 
 
 The apothecia vary from rather small to medium in 
 size. They are flattened or cup-shaped, lateral, occur- 
 ring either along the margin or upon the flat surface. 
 Disk pale brown. Spores are colorless, elliptical, two- 
 celled. 
 
 The Ramalinas occur upon trees and rocks ; they 
 are not plentiful. 
 
 i. Ramalina minuscula. Thallus minute, half an 
 inch or less in height, branches canaliculate ; ter- 
 minal branches very short ; soralia sometimes present ; 
 color light-gray. Apothecia and spores not seen. 
 
 2. RarnaUna calicaris. Thallus one or two inches 
 in height ; lobes comparatively thin and broad, some- 
 what canaliculate aud slightly reticulate, green. Apo- 
 thecia of medium size, terminal tendency, somewhat 
 cup-shaped. Disk light-brown. Spores typical, not 
 curved, 10.5/x, X 5.5/a. 
 
 Most authors recognize a number of varieties, some 
 of which no doubt deserve the rank of species. R, 
 
Oenera and species. 161 
 
 caUcaris has a wide range and usually occurs upon 
 trees (oak in particular) ; it is also said to occur upon 
 rock. The species has been made use of as a gum in 
 calico-printing, in the preparation of "parchment" 
 andpasteboard, and in the manufacture of hair-pow- 
 ders. The soralia-bearing specimens (mealy Ramalina 
 calicaris) have been highly recommended as an arti- 
 cle of diet. It has also found a use in the treatment 
 of chilblains and chapped hands. A variety obtained 
 from Teneriife yields a yellow dye. According to 
 another authority the species yields a rich red dye 
 equal to that obtained from Rocella tinctoria which 
 was used in dyeing silken and woollen goods. The 
 plant was said to have brought $5,000 per ton in 
 England. 
 
 3. Ramalina homalea. Thallus large, rather spar- 
 ingly branched, lobes ribbon-like, thick, rigid, smooth, 
 not canaliculate ; gray to brown. Apothecia medium, 
 with a terminal tendency, sometimes distinctly cup- 
 shaped. Disk about the same color as the thallus. 
 Spores typical, somewhat curved, loya X 5/x. 
 
 This lichen is essentially southern, and occurs upon 
 rocks. It is no doubt rich in coloring properties. 
 
 ^. Ramaliud cenichis. Thallus rather small, spar- 
 ingly branched, lobes somewhat flattened to nearly 
 cylindrical, gray ; smooth, becoming dark spotted. 
 Apothecia medium, cup-shaped. Disk about the same 
 color as thallus. Spores typical, not curved, 15/x X -^f^' 
 
 5. Ramalina polymorpha. Thallus long, much 
 branched ; lobes narrow, flattened, bearing large 
 soralia. Apothecia rare. Spores, 14/x X ^Z^*- 
 
162 GUIDE TO THE STUDY OF LICHENS. 
 
 6. JRamalina rigida. Thallus long and much 
 branched ; lobes very slender, flattened, gray. Apo- 
 thecia rather small, lateral, not cup-shaped. Disk 
 somewhat convex, color of thallus. Spores typical, 
 oblong, not curved, 21/x X 4/x. 
 
 7. Bamalina reticulata. Thallus very long (sev- 
 eral feet), pendulous, much branched ; lobes slender, 
 flattened, reticulately perforate. Apothecia lateral, 
 small. Disk convex and of the same color as the 
 thallus. Spores typical, curved, 14/x X 7/x. 
 
 This lichen is at once recognized by the reticulate 
 perforations of some of the lobes, or perhaps more cor- 
 rectly the reticulate branching of certain portions. It 
 is southern and occurs upon trees. 
 
 9. Rocella. 
 
 This is a typically fruticose genus. The thallus is 
 sparingly branched, lobes flattened, rigid, thick, not 
 canaliculate ; edges rounded. Color gray to some- 
 what purplish. Large discoid soralia frequently 
 occur along the margin of the lobes. The apothecia 
 are small, marginal, not terminal, and characterized by 
 a black hypothecium, a characteristic not found in any 
 other genera of the family. Disk flattened, dark to 
 black. The algae are Chroolepus. These two characters 
 are in contrast to the other generic groups of the fam- 
 ily and seem to indicate that the genus is perhaps mis- 
 placed. As has already been indicated, Reinke and 
 others place the group with the Graphidacece. The 
 gross characters, however, indicate a relationship to 
 Ramalina* 
 
PLATI'! \'. Fniiicnsf TviM'. In i lif pii\ -iic c. 
 i:. S. (;i;,y. naklaii.l. Calif. Fim,, |{,.,|\v. 
 lliUiudiiiK rdinilalii i> a iiiosi irinaiUalilr lidir 
 in large loiin tiitis. oftrii .•..ntii-.-.l uiili fsn, 
 
 ,( I 
 
 •tloll (.f 
 
 (alii. 
 
 InW iiiix 
 
GENERA AND SPECIES. 163 
 
 The Rocellas are essentially tropical, occurring on 
 rock along the sea-coast. Less frequently they occur 
 upon trees. The American specimens are found prin- 
 cipally in Lower California. 
 
 1. Roceila tinctoria. Thallus quite large, sparingly 
 branched, lobes long, usually flattened, but often be- 
 coming rounded, gray to purplish. Apothecia com- 
 paratively rare, lateral, medium. Disk flattened to 
 slightly convex, black. Lateral white soralia. Spores 
 colorless, oblong, four-celled, 20/x X 7/x. 
 
 This lichen occurs plentifully along the Mediter- 
 ranean coast. It occurs, in fact, in all tropical coun- 
 tries. Its uses as a dyeing agent have already been 
 referred to. It also found a use in the treatment of 
 coughs and in diseases of the kidneys. For the latter 
 purpose it was largely collected from the island of 
 Mauritius. 
 
 2. Roceila leucophcBa. Thallus large, branching, 
 lobes flattened, gray. Apothecia lateral, medium size. 
 Disk flattened, black. Lateral white soralia. Spores 
 
 typical, 21/x X 8/"- 
 
 The occurrence and use of this lichen are similar to 
 those of R. tinctoria. 
 
 10. Evernia. 
 
 There seems to be considerable uncertainty as to 
 the limitation of this genus. As represented by the 
 two types given below, there is certainly a wide differ- 
 ence in anatomical characters. 
 
 The thallus is generally f ruticose, large ; the branches 
 are irregularly angular and not distinctly flattened. 
 The surface of the thallus has the appearance of hav- 
 
164 GUIDE TO THE STUDY OF LICHENS. 
 
 ing been besprinkled with a mealy substance. Color 
 varies from yellowish to grayish-green or bluish-gray. 
 Apothecia, when present, are quite large, discoid, often 
 bearing filiform thalloid branches. Disk of a different 
 color from the thallus. The spores are small, simple, 
 oval, colorless ; resembling those of Cetraria. 
 
 1. Evernia furfuracea. Thallus large, much 
 branched, foliose, but pendulous upon branches of 
 trees ; bluish-green, tinged with gray ; channelled 
 below, light-gray. Usually sterile. Apothecia not 
 seen. 
 
 This lichen is striking in appearance and in the 
 eastern states occurs almost wholly upon pine trees in 
 mountainous districts. It is a handsome, soft, pliable 
 plant, which is only very loosely attached to the 
 branches of the tree. Some authors place it in the 
 group Physcia, 
 
 This species was at one time highly recommended as 
 a substitute for quinine. It yields a red dye. The 
 Egyptians at one time employed it in the making of 
 bread and in the preparation of hair-powders. 
 
 2. Evernia vulpina. Thallus large, typically fruti- 
 cose, branches angular, ridged, thickness of branches 
 decreasing toward the top ; lemon color. Apothecia 
 very large, terminal tendency, margin and lower sur- 
 face bearing thalloid filaments. Disk brown, concave. 
 Spores colorless, elliptical, simple, 7.5/x X 5.5^. 
 
 This is the noted "Ulf-mossa" (Wolf's moss) of 
 the Swedes. It was so named from the popular belief 
 that the plant was poisonous to wolves. The lichen 
 was powdered and mixed with powdered glass ; the 
 
'LATK IV. Fnilic.s,. I'vpc. ('alif..i-iii:i Aca.lciny SfiiMu-e. 
 
 Kcet'niii ciilpiita. 'i'liis is a t\iiit:illv wcsit-ni species, 
 
 and thoiiuli trmicti.se lias niany itt ihc cliaracteis of 
 foliose lichens. 
 
GENERA AND SPECIES. 165 
 
 mixture was then smeared over some dead animal 
 placed in a locality frequented by the wolves. It was 
 also used to dye woollen goods a bright yellow. 
 
 This is the most showy and largest lichen found 
 along the Pacific coast, where it usually occurs fertile ; 
 the specimens found in the interior and eastern states 
 are small and always sterile. 
 
 11. Alectoria. 
 
 This genus has only a few representatives. The thal- 
 lus is typically fruticose, long and pendulous. At the 
 joints the thallus is somewhat flattened, otherwise the 
 branches are cylindrical. There is a semblance to 
 Usnea, but the surface is smoother and the apothecia 
 are smaller. The color varies from light to brown 
 and nearly black. Oval soralia are c^ten present. 
 The apothecia are few, sessile, small to medium. Disk 
 flattened or convex. Spores colorless to dark, simple, 
 two to four in each spore-sac, large, with thick outer 
 spore-wall. The spores remain colorless until matur- 
 ity, when the cell-contents become dark. Oil-globules 
 are frequently present in the spores. 
 
 The Alectorias occur in arctic regions and upon 
 high mountains. They grow upon coniferous trees. 
 
 1. Alectoria sarmeyitosa. Thallus long, pendulous, 
 branched ; flattened at joints ; straw color ; surface 
 smooth or bearing oval soralia. Apothecia few, 
 medium, lateral. Disk light color to brown. Spores 
 typical, 32/u, X 17.5/x. 
 
 This plant is usually described as A. ochroleuca var. 
 sarmentosa ; also as C. ornicularia ochroleuca. 
 
166 GUIDE TO THE STUDY OF LICHENS. 
 
 12. Bryopogon. 
 
 This group is evidently closely related to Alectoria, 
 as is indicated by the histological characters. The 
 thallus is long, pendulous, typically fruticose ; much 
 branched, lobes cylindrical, only slightly compressed at 
 the joints. In a transverse section of the thallus it is 
 found to be nearly hollow in the middle, no central 
 core being present (also true of Alectorid). Color 
 black. Apothecia few, small to medium, lateral. 
 Disk dark, entire, somewhat convex. Spores are 
 small, simple, colorless, eight in each spore-sac (nor- 
 mal number). It must also be kept in mind that the 
 Alectorias as well as Bryopogons are frequently sterile. 
 
 The species occur upon rock, soil, trees and ferns 
 in the higher altitudes and latitudes. 
 
 1. Bryopogon Oregana. Thallus comparatively 
 small, more or less erect, much branched, compara- 
 tively rigid, black. Apothecia medium, comparatively 
 numerous. Disk dark to black. Spores typical, 6/a 
 X 4.5;a. 
 
 2. Bryopogon juhata. Thallus long, pendulous, 
 much branched, branches long and entangled, some- 
 times bearing soralia, brown to black. Apothecia 
 very few or wanting, lateral. Disk of same color as 
 thallus. Spores typical of the genus. 
 
 This is without doubt a most striking lichen. In 
 its perfect development it resembles a tuft of woman's 
 tresses. Because of such a resemblance it has been 
 designated as " tree or rock hair." It has also been 
 called " horse-tail lichen," but this name is less apt 
 
GENERA AND SPECIES. 167 
 
 since the thallus is less rigid than the hair of the 
 horse's tail. 
 
 B.jubata, and perhaps also other species, yields a 
 red dye. Reindeers feed upon it when Cladonia ran- 
 giferina is not obtainable. Laplanders are said to 
 cut down the trees upon which it grows so that the 
 reiudeer may have more ready access to the lichen. 
 
 13. Usnea. 
 
 Thallus fruticose, pendulous, large, much branched ; 
 lobes cylindrical, or rarely flattened, decreasing in 
 size in an acropetal (toward apex) direction. Main 
 branch quite thick and rigid. The surface is less 
 smooth than in the thalli of Alectoria and Bryopogon ; 
 often it is circularly fissured. Soralia are quite rare. 
 Upon making a transverse section of the thallus it is 
 found to contain a rather firm central core of longi- 
 tudinal hyphae. The prevailing colors of the thallus 
 are grayish-green, pale brownish-green or straw color. 
 The apothecia are very variable in size, lateral to 
 terminal. Spores small, simple, elliptical, colorless. 
 
 The Usneas are somewhat northern in their range. 
 They occur upon trees in the higher altitudes. Con- 
 siderable confusion exists as to the limitations of some 
 species and varieties, as, for example, Usnea harhata 
 and its real or imaginary varieties. The following 
 are the more common species irrespective of varieties. 
 
 1. Usnea linearis. Thallus medium, of several 
 main branches, bearing numerous long, slender, cylin- 
 drical branches ; greenish-gray. No fertile specimens 
 have come to notice. 
 
168 GUIDE TO THE STUDY OF LICHENS. 
 
 By many collectors this plant is designated as U» 
 harbata. It occurs on trees in proximity to U. barbata. 
 
 2, Usnea barbata. Thallus medium, much branched ; 
 branches comparatively rigid, transversely fissured, 
 especially the larger main branches, greenish-gray. 
 Apothecia numerous, very large, bearing filiform 
 branches. Disk somewhat concave, light-brown color. 
 Spores typical, 8/x X 5/^* 
 
 This is the " beard-moss " or " tree-moss " of poets 
 — the " idle moss " of Shakespeare. It is a cosmo- 
 politan plant; it occurs plentifully in the arctic 
 regions as well as in the tropics. In some coun- 
 tries it is eaten by wild animals or is collected and 
 preserved as fodder for domestic animals. Bertram 
 states that the Pennsylvanians prepared from it an 
 orange dye, and Humboldt states that the South Ameri- 
 cans used it for dyeing purposes. In the past ages it 
 enjoyed an extensive use as a remedial agent. It was 
 used as an astrigent, tonic, diuretic ; it was highly 
 recommended for whooping-cough, and as an anodyne. 
 It formed the basis of hair-powders and perfumes and 
 was thought serviceable in the preparation of explo- 
 sives. Boiled in beer it was said to cure catarrh 
 and dropsy. The Laplanders used it in the treatment 
 of scald head, and scrofula of children. 
 
 3. Usnea longissima. Thallus much elongated, 
 branched, lobes somewhat flattened, greenish-gray. 
 Apothecia rare or wanting. Spores typical, 9/>(, X 5/x. 
 
 The thallus is much longer than in JJ. barbata, and 
 also more slender and pendulous. It occurs mostly 
 upon trees on high mountains. 
 
PLATE VI. Fruticoso Type. Redwood Canyon. Marin 
 Co., California. Usnea harhafn, tlio familiar ••beard 
 moss. ' ' 
 
GENERA AND SPECIES. 
 
 169 
 
 VII. VERR UCA RIA CE^. 
 
 The representatives of this family are characterized 
 by small globose apothecia, which are either immersed 
 in the substratum (bark or rock) or in the thallus {Der- 
 matocarpon and Endocarpon). In the majority of 
 genera the thallus is crustose, even wholly hypophloeo- 
 dal or hypolithic. Another characteristic of the fam- 
 ily is the indistinct, slender, gelatinized paraphyses. 
 
 With the exception of Endocarpon the members of 
 the family are insignificant in appearance; in fact, 
 some are very doubtful lichens, as, for example, most 
 of the Pyrenulas and some species of Trypethelium. 
 
 Two algal types exist in this family: Ghroolepus 
 occurs in the genera from Trypethelium to Verrucaria, 
 Pleurococcus occurs in Verrucaria, Dermatocarpon 
 and Endocarpon. It must, however, be born in mind 
 that the algal symbiont may vary in different in- 
 dividuals of the same species. This change in sym- 
 bionts requires further study. 
 
 KEY TO THE GENERA. 
 
 Crustose thallus. , , ^ , 
 
 Thallus scarcely visible, mostly hypophloeodal. < 
 Spores six to eight-celled, colorless . 1. Trypethelium. 
 
 Spores four-celled, brown 2. Pyrenula. 
 
 Spores many-celled, colorless . . . 3. Conotrema. 
 Spores multilocular, colorless. 
 
 Spore-wall normal 4- Thelolrema. 
 
 Spore-wall thick 5. G/postomum. 
 
 Thallus visible, mostly epiphloeodal or epilithic. 
 Spores simple, colorless. 
 
 Medium size ^- lerrucana. 
 
 Very large ^- Pertusario. 
 
 Foliose thallus.^ntiro ; spores colorless. 
 
 Spores multilocular: thallus minute . S. Dermatocarpon. 
 Spores simple ; thallus large . . . . 9. Endocarpon, 
 
170 GUIDE TO THE STUDY OF LICHENS. 
 
 1. Trypethelium. 
 
 The thallus is hypophloedal during its entire existence. 
 It consists simply of a deficient network of hyphse en- 
 closing a few algae (^Chroolepus). The bark over the 
 apothecia and thallus is smooth and of a rusty-red 
 color which gradually fades into brownish or green- 
 ish. 
 
 The apothecia are likewise hypophloeodol, and occur 
 in clusters of from five to forty. Each apothecium is, 
 however, independent of its neighbors, and may be 
 considered as an individual of the colony. As the 
 apothecia grow, they push up the superimposed bark 
 mi til it forms a more or less irregular elevation. The 
 spores escape through minute apical pores. 
 
 The spores are normally colorless and eight-celled, 
 spindle-shaped ; the plasmic masses diamond-shaped. 
 
 The genus is essentially southern. The representa- 
 tives occur upon trees. Some authors combine it with 
 Pyrenula. 
 
 li Trypethelium virens. Bark above thallus smooth, 
 light-brown to pale-green. Apothecial colonies con- 
 sist of from ten to forty minute apothecia. Perithe- 
 cium black. Spores colorless, six to eight-celled, 
 42/x X 10/x. 
 
 Bark is tinged reddish or rusty brown, over and 
 about the apothecia. Nearly all of the so-called 
 species of Trypethelium require further study. 
 
 2. Pyrenula. 
 
 This is another lowly-organized lichen-genus. The 
 thallus as well as the apothecia are hypophloeodal, and 
 
GENERA AND SPECIES. 171 
 
 morphologically resemble similar structures of the pre- 
 ceding genus. Sometimes tlie apothecia occur singly, 
 but they also occur in colonies. The perithecium is 
 black. The spores are usually colored dark, four-celled, 
 otherwise resembling those of Trypethelium. 
 
 The representatives of this genus are mostly south- 
 ern in their range. They occur upon the smoother 
 barks. In many the thallus is very rudimentary, so 
 that the algae (Chroolepus) can only be found after 
 careful search. 
 
 1. Pyrenula aspistea. Bark over thallus brown, 
 smooth. Apothecia small, numerous, black. Spores 
 typical, constricted at transverse septa, 17/u, X 8.5/x. 
 
 2. Pyrenulu nitida. Bark over thallus greenish or 
 yellowish-brown. Apothecia larger, fewer, and more 
 scattered than in P. aspistea, black. Spores typical, 
 not constricted, 14/a X 7.5/x. 
 
 3. Conotrema. 
 
 The thallus is in part epiphloeodal, thin, evenly 
 spreading to indistinctly areolate. The alga? are Pro- 
 tococcus instead of Chroolepus. The apothecia are 
 urn-shaped, less hypophloeodal than in Pyrenula and 
 larger. They break through the superimposed bark 
 and have distinct apical pores from which the spores 
 escape. Disk light color. Spores are long, filament- 
 ous, with numerous transverse septa ; when once seen 
 they will not be mistaken. 
 
 The genus requires further study ; only one species 
 has come to notice ; it occurs upon trees, those of 
 the smoother barks, as Betula and Acer. 
 
172 GUIDE TO THE STUDY OF LICHENS. 
 
 1. Conotrema urceolatum. Epiphloeodal portion of 
 thallus evenly spreading, thin, whitish. Apothecia 
 urn-shaped when fully matured, partially enclosed 
 by thallus. Disk of a waxy color, margin black. 
 Spores typical of genus, 140/x, X V- 
 
 ^. Thelotrema. 
 
 As in Conotrema, the thallus is rudimentary and 
 partly hypophloeodal. The algag are Chroolepus. 
 
 The apothecia are characteristic. They resemble a 
 miniature volcanic crater. They are numerous and 
 quite uniformly scattered over the thallus. Upon ex- 
 amining the opening at the top the whitish perithecium 
 can be seen within ; that is, the perithecium becomes 
 separated from the more inflexible cone. A whitish, 
 waxy coloration pervades the entire plant. 
 
 The spores are large, colorless, multilocular, spindle- 
 shaped, with a thick rugose spore-wall. 
 
 There is a considerable number of species which 
 occur upon trees in the warmer latitudes. 
 
 1. Thelotrema lepadinum. Thallus thin, uniformly 
 spreading, smooth, white to cream color. Apothecia 
 usually numerous, conical, immersed, with a circular 
 opening through which the light-colored perithecium 
 can be seen. Spores large, colorless, spindle-shaped, 
 12 to 16 transverse septa, and a few longitudinal septa 
 at the middle. Spore-wall thick, rugose, 51^ X 13/x. 
 
 5, Gyrostomum. 
 
 Thallus rudimentary. Apothecia quite small and 
 semi-globose. Both thallus and apothecia begin their 
 
GENERA AND SPKCIES. 173 
 
 development below the surface of the substratum. 
 The apothecia at maturity open by an apical pore which 
 renders them urn-shaped. The perithecium is black. 
 The spores are colorless, multilocular, with a thick 
 gelatinous outer spore-wall which is not rugosely 
 folded. 
 
 Only one species came to my notice, which is south- 
 ern and grows upon various trees. 
 
 1. Gyrostomum scyphidiferum. Thallus 'rudiment- 
 ary, uniformly spreading, greenish-gray to brownish. 
 Apothecia small, somewhat urn-shaped when mature. 
 Disk dark to black. Spores typical of the genus, 
 
 35)u, X 13/X-. 
 
 6. Verrucaria. 
 
 Thallus distinctly crustose and mostly epilithic or 
 epiphloeodal. It begins its development, however, be- 
 low the surface of the substratum. In the rock-species 
 the thallus begins its development upon the surface, 
 but the lichen-acids disintegrate the rock, and the 
 greater portion of the thallus (hypha?) becomes im- 
 bedded in the loosened particles. The algie are evi- 
 dently Fleurococcus, though some authors report 
 Chroolepus as the generic alga. 
 
 The apothecia are small, globose, more or less im- 
 mersed in the thallus and substratum, perithecium 
 dark or black. The paraphyses and spore-sacs are 
 much gelatinized ; so much so that they are scarcely 
 discernible. The spores are simple, elliptical, color- 
 less, and thin-walled. They generally bear oil-glob- 
 ules. 
 
 The Verrucarias have a wide range, and occur upon 
 
174 GUIDE TO THE STUDY OF LICHENS. 
 
 rock, perhaps rarely upon trees. The majority of so- 
 called tree Verrucarias belong to other genera. 
 
 1. Verrucaria rupestris. Thallus deficient, dark 
 or dirty color. Apothecia small, partially immersed ; 
 perithecium black. Spores typical, 15/x X 6.5/x. 
 
 2. Verrucaria pyrenophora. Thallus rudimentary, 
 uniformly spreading, gray. Apothecia small, raised 
 above the thallus. Disk somewhat flattened, black. 
 Spores not found. 
 
 3. Verrucaria nigrescens. Thallus granular to in- 
 distinctly areola te, dirty gray to nearly black. Apo- 
 thecia numerous, medium size, black. Spores typical, 
 12/A X 7.5/x. 
 
 ^. Verrucaria muralis. Tliallus indistinctly areo- 
 late, light to pale brown. Apothecia numerous. Disk 
 projecting somewhat above thallus, black. Spores 
 typical, 13/A X 8/ix. 
 
 This lichen frequently occurs on brick, mortar, lime- 
 stone, etc. 
 
 5. Verrucaria fuscella. Thallus comparatively 
 thick, distinctly areolate, dirty gray to nearly black. 
 Apothecia small, immersed, black. Spores typical, 
 13.5/x X 6.5/x. 
 
 6. Verrucaria margacea. Thallus thick, areolate, 
 surface smooth ; clay color. Apothecia numerous, 
 almost entirely immersed, black. Spores large, pale 
 yellowish, otherwise typical, 30/>t X 13.5/li. 
 
 7. Pertusaria. 
 
 Thallus crustose, but more highly developed than 
 in Verrucaria, though it varies considerably in thick- 
 
GENERA AND SPECIES. 175 
 
 ness. Its color varies from gray to greenish-gray. 
 The algae are Protococcus. Soralia are quite common 
 and seem to attain a high development in this genus. 
 Darbishire, who has made a special study of the soralia 
 of the Pertusarias, is inclined to the view that they 
 are phylogenetically derived from apothecial structures. 
 
 The apothecia are globose and immersed in warty 
 elevations of the thallus. Usually there is no percep- 
 tible pore-opening. Absence of any marked coloration 
 of the apothecia is characteristic. Spores are simple, 
 large, colorless, one or two in each spore-sac. The 
 inner spore-wall is reticulately marked in some species ; 
 oil-globules are often present. 
 
 Most of species are cosmopolitan ; they occur upon 
 bark and rock, less commonly upon moss. 
 
 1. Pertusaria pustulata. Thallus very deficient, 
 grayish. Apothecia entirely immersed in the substra- 
 tum, producing pustular elevations and finally opening 
 by a minute apical pore. Spores typical, but inner 
 wall not reticulate, 75/x, X 43/x. 
 
 2. Pertusaria leioploca. Thallus deficient of scat- 
 tered apothecial warts, greenish-gray to yellowish- 
 brown. Apothecia wholly immersed in the warts. 
 Spores typical (nor reticulate), usually four to six in 
 each spore-sac, 60/m X 22/i. 
 
 3. Pertusaria multipuncta. Thallus usually entire, 
 somewhat fissured, sometimes rugose or areolate, pale 
 ash-gray. Apothecia immersed in thalline warts, 
 single or confluent. Spores typical, inner spore- wall 
 reticulate, 15CV X 60/>t. 
 
 Jf.. Pertusaria glohularis. Thallus thin, apothecial 
 
176 GUIDE TO THE STUDY OF LICHENS. 
 
 warts united in groups of from two to six ; gray. Apo- 
 thecia entirely immersed, small pore often visible. 
 Spores typical but not reticulate, 95^ X 33/x. 
 
 5. Pertusaria glomeridata. Thallus consists of 
 numerous confluent apothecial warts, nearly white to 
 gray. Apothecia immersed, opening by small pores. 
 Spores typical, inner wall reticulate, loO/x X 60/x. 
 
 6. Pertusaria communis. Thallus thick, rugose 
 and somewhat fissured, gray. Apothecia in groups, 
 immersed in apothecial warts, apical pore present. 
 Spores typical, inner wall reticulate, 1 50/x X 47/*. 
 
 This species, as well as other species of the genus, 
 were formerly included among the PseudoUchenes or 
 Lichenes imperfecti, under the name of Variolaria. 
 P. com. contains a large percentage of oxalate of lime 
 and had been used in France as the source of oxalic 
 acid. It was used as a remedy in feyers and as an 
 astringent in intestinal troubles. Many Pertusarias 
 were more or less recommended in the dyeing industries. 
 
 1. Pertusaria velata. Thallus thick, areolate, light- 
 gray. Apothecial warts bearing apothecia which 
 open by apical pores showing the pale disk. Spores 
 yery large, typical, but not reticulate, 180/x, X 65/x. 
 
 8. Dermatocarpon. 
 
 The only representatiye of this genus which came to 
 notice is generally included in the genus Endocarpon. 
 
 The thallus is yery minute for a foliose type. Care- 
 ful search with a pocket lens is necessary to detect it. 
 It consists of a single entire lobe closely adnate to the 
 substratum (rock) and is of a dark color. Several of 
 
I'LATK Ir. Cruslosc 'l^vpos. Kr..iii ihc i-(«ii»'i'i k.ii oi \. 
 Y. Chirk in tlie liriliariiim nt ilir ( alifoiiiia Ai'utleiiiy oi 
 Scieiii'*'. I'ertitsKriii vrlafn. 
 
GENERA AND SPECIES. 177 
 
 these minute lobes usually occur in close proximity. 
 The algje are Pleurococcus as in Verrucaria. 
 
 The apothecia are very small, usually one is im- 
 mersed in each thallus-lobe- Quite generally minute 
 single-celled algse {^Pleurococcus'^) occur above the 
 thecium ; these are known as thecial algse, and are 
 ejected with the spores and enter into a symbiotic re- 
 lationship with the germinating spore. The spores 
 are colorless, multilocular, thus differing from those of 
 Verrucaria and Endocarpon. 
 
 The only species occurs upon limestone, and seems 
 to be southern in its range. 
 
 1. Dermatocarpon pusillum. Thallus-lobes entire, 
 minute, widely scattered, closely adnate to the substra- 
 tum, dark. Apothecia typical of the genus. Spores 
 typical, two or three in each spore-sac, 23.5/x X 18.5/x. 
 
 9. Endocarpon. 
 
 In this genus the thallus is large, typically foliose, 
 entire ; attached by a central portion (umbilicus) con- 
 sisting either of a single lobe or numerous, more or 
 less plicate, lobes. The thallus is quite thick and rigid 
 and much less brittle than in Umbilicaria and Gyro- 
 phora. Color gray to dark-gray. 
 
 The apothecia are small, globose and entirely im- 
 mersed in the thallus, opening by small dark pores, 
 which are scattered over the thallus. The spores are 
 simple, colorless, elliptical, the usual number (8) oc- 
 curring in each spore-sac. 
 
 The Endocarpons occur principally upon rock, also 
 upon soil and the bark of trees. 
 
178 GUIDE TO THE STUDY OP LICHENS. 
 
 1. JEndocarpon hepaticum. Thallus of orbicular 
 scattered entire lobes, variable in size, closely ad- 
 nate to substratum (soil), margin turned upward, 
 pale flesh color, changing to dark-brown ; soralia some- 
 times present. Apothecia immersed. Spores typical, 
 13.5ya X V 
 
 The color of the thallus is very likely due to 
 the presence of oxide of iron taken up from the 
 soil. 
 
 2. Enndocarpon arhoreum. Thallus quite large, 
 somewhat lobate, margin usually turned downward, 
 attached by numerous long black rhizoids, upper 
 surface gray to light-brown ; lower surface dark. 
 Apothecia immersed, scattered. Spores typical, 13/x 
 X5/X. 
 
 3. Endocarpon Jluviatile. Thallus quite large, 
 lobate at margin, only loosely attached to substra- 
 tum, upper surface gray to dark ; lower, gray to brown ; 
 few rhizoids. Apothecia not seen. 
 
 Jf.. Endocarpon miniatwn. Thallus large, entire, 
 attached by an umbilicus, upper surface smooth, gray 
 to dark ; lower surface pustulate, dark to black, with 
 numerous fine rhizoids. Apothecia immersed and uni- 
 formly scattered, appearing as minute dark specks. 
 Spores typical, 13.5/x X 5/x. 
 
 The pustules on the lower surface prove on exami- 
 nation to be apothecia, bearing spores. A so-called 
 variety consists of numerous imbricate ascending lobes 
 instead of a single thallus. 
 
 A coloring substance is extracted from this lichen, 
 which is, however, said to be of an inferior quality. 
 
GENERA AND SPECIES. 179 
 
 VII I. COLLEMACEJS. 
 
 This family is characterized by a foliose, dark-blue 
 thallus, which is highly gelatinous when moist. As a 
 rule, the thallus is thin and more or less lobate, at- 
 tached by an umbilicus. The surfaces are frequently 
 rugosely folded. Soralia are deficient. Rhizoids are 
 also deficient excepting in the genus Mallotium. The 
 algai are Nostoc, excepting perhaps in Hydrothyria. 
 In all cases they are bluish-green, and occur in chains. 
 This one character alone suffices to mark the repre- 
 sentatives of the family. Owing to the supposition 
 that the algae are not arranged in such well-defined 
 layers as in the other foliose forms these lichens are 
 spoken of as homoimerous. The algae are, however, 
 arranged in more or less definite layers, especially in 
 the groups above Collema. 
 
 The apothecia are rather small, discoid and sessile 
 upon the thallus. Spores vary in form and septation, 
 and are mostly colorless. 
 
 KEY TO THE GENERA. 
 
 Cortical layers wanting 1. Collema. 
 
 Cortical layers present. 
 
 Rhizoids deficient, thallus thin. 
 
 Lower surface of thallus not veined . 2. Leptogium. 
 Lower surface of thallus veined . . . 3. Hydrothyria. 
 Rhizoids long, numerous, thallus com- 
 paratively thick 4' Mallotium. 
 
 1. Collema, 
 This genus is represented by many species. The 
 thallus varies from small and almost fruticose to quite 
 large and typically foliose. The amateur will have 
 
180 GUIDE TO THE STUDY OF LICHENS. 
 
 no trouble in recognizing the more typical representa- 
 tives. The dark-blue to almost black gelatinous 
 (when moist) thin thallus is characteristic ; these 
 general characteristics, however, also apply to Lepto- 
 gium. Upon a microscopical examination it is found 
 that no cortical structure is present in Collema. The 
 algae {Nostoc) and hyphae are loosely intermingled. 
 The margin of the thallus is more or less divided or 
 lobed. 
 
 The apothecia are small to medium in size, discoid, 
 sessile upon the thallus. Disk concave, flattened or 
 slightly convex, usually brown or reddish-brown. 
 
 The spore-characters are very variable. They may 
 be simple, two to many-celled and multilocular. Upon 
 further careful study it will no doubt be possible to 
 subdivide the genus upon its spore-differences. Usually 
 the spores are colorless ; faintly colored spores, how- 
 ever, occur. 
 
 The Collemas occur upon soil, bark, rock, and are 
 even found partially or wholly submerged in water. 
 They seem to be somewhat western in their raia^e ; they 
 are, however, also common sooth and east. 
 
 1. Collema pycnocarpiim. Thallus medium, ascend- 
 ing lobes divided and narrowed ; from yellowish-brown 
 at the base to dark-blue green above. Apothecia very 
 numerous, terminal and marginal margin not elevated. 
 Disk convex, reddish-brown to dark-brown. Spores 
 two-celled, colorless, elliptical, 13.5/x X 6.5/x,. 
 
 2. Collema cyrtaspis. Thallus much as in C. pycno- 
 carpum, larger and darker in color. Apothecia some- 
 what larger, crenate margin raised above the flattened 
 
GENERA AND SPECIES. 181 
 
 dark-brown disk. Spores four to six-celled, colorless, 
 spindle-shaped, 16/i, X ^f"- 
 
 3. CoUema myriococcum. Thallus medium, lobes 
 ascending, more or less flexed and folded, surface 
 somewhat granular or warty, dark-blue to black. 
 Apothecia not seen, said to be small, numerous and 
 somewhat immersed. Spores simple, colorless, 
 Ufx X 8/x. 
 
 4. Collema leucopepla. Thallus thin, lying flat upon 
 the substratum, rather indistinctly lobate, wrinkled 
 above and below, often granular ; dark-green above, 
 somewhat paler beneath. Apothecia rather small. 
 Disk reddish-brown, with a translucent whitish tinge. 
 Spores acicular, four to six-septate, 51/a X 3/x. 
 
 5. Collema nigresceiis. Thallus much as in C. leu- 
 copepla. Apothecia small, numerous. Disk flattened 
 to convex, dark-brown. Spores acicular, resembling 
 those of Bacidea, four to six-septate, 35/x X 3yu,. 
 
 6. Collema ryssoleum. Thallus large, thin, lobes 
 ascending ; wrinkled and rugosely folded above, reticu- 
 late below ; dark-green above, somewhat paler beneath. 
 Apothecia small, much as in C. nigrescens. Spores 
 colorless, spindle-shaped, 21/a X 6.5/x. 
 
 7. Collema pulposum. Thallus medium, compara- 
 tively thick, lobes imbricate and somewhat ascending, 
 smooth, margin crenulate ; leek-green to dark. Apo- 
 thecia large, numerous, margin crenate and warty, ex- 
 tending above the concave brown disk. Spores color- 
 less, spindle-shaped to ovoid, elliptical, four to six- 
 celled, rarely multilocular, 21/x X 7.5/x. 
 
 8. Collema laciniatum. Thallus rather small, lobes 
 
182 ' GUIDE TO THE STUDY OF LICHENS. 
 
 long, margin bearing short small branchlets ; dark 
 above, lighter beneath. Apothecia numerous, on short 
 thalloid branches, margin somewhat crenulate, dark. 
 Disk dark. Spores colorless, two-celled, small, 
 
 9. Collema pUcatile. Thallus comparatively small, 
 lobes narrowed, ascending, margin somewhat crenu- 
 late ; nearly black above, somewhat less dark beneath. 
 Apothecia small, on short thalloid branches, margin 
 somewhat raised. Disk nearly black. Spores multi- 
 locular, oblong, irregular outline, constricted at the 
 septa, 24/t X 6/x. 
 
 10. Collema crispum. Thallus medium size, com- 
 paratively thick, margin thickened and indistinctly 
 crenulate ; dark above, less dark beneath. Apothecia 
 numerous, marginal, cup-shaped, margin crenulate and 
 warty. Disk dark-brown. Spores multilocular, color- 
 less, somewhat constricted at septa, 27yw, X 12/x. 
 
 11. Collema Jlaccidum, Thallus large, lobes large, 
 only slightly ascending, more or less folded and warty ; 
 dark-blue, lighter beneath. Apothecia small, upon 
 surface of thallus, margin entire and raised above the 
 reddish-brown disk. Spores colorless, four to six- 
 celled, 23/x X 6/x. 
 
 2. Leptogium. 
 
 The thallus resembles the thallus of Collema. It is 
 somewhat larger, thicker, and more rigid. The essen- 
 tial difference is made apparent upon a microscopical 
 examination. In Leptogium there is a cortical struct- 
 ure consisting of a single row of cells. This cortical 
 tissue is more highly developed in the apothecium, 
 
GENERA AND SPECIES. 183 
 
 where it attains considerable thickness, otherwise 
 the apothecia are as in Collema. The spores liave 
 tlie general characters of the spores in Collema. 
 
 There can be little doubt that this genus is simply a 
 somewhat higher evolution than Collema. The two 
 genera correspond in habitat and range. 
 
 Although a considerable number of species are 
 known, we shall content ourselves with the description 
 of a single species. 
 
 1. Leptogium chloromelum. Thallus medium to 
 large, much wrinkled and folded, margin of lobes 
 turned upward, bearing numerous isidioid outgrowths, 
 dark-green. Apothecia medium, margin somewhat 
 elevated, slightly rugose. Disk dark-brown. SjDores 
 colorless, multilocular, granular, 20/a X 12/x. 
 
 3. Hydroihyria. 
 
 Thallus quite large, flat, lobed, dark ; distinctly 
 veined below. The veins are simply bundles of 
 hyphasi. The genus is represented by one species 
 only. It is peculiar in that its habitat is on rock in 
 clear running water, in which position it matures its 
 spores. As a rule, lichens do not thrive in very moist 
 places. Some doubt exists as to the nature of the 
 symbiotic algic. Some authors maintain that they are 
 Rlvularia. They certainly are not normal Rivularia ; 
 it is likely that they are modilied Nostoc. Further 
 study is necessary to determine tliis ])oinr. 
 
 1. Hydrothyria venosa. Tliallus large, tliin, lobes 
 large, smootlu dull gray when dry ; somewhat paler 
 beneath and bearing branching veins. Apothecia few, 
 
184 GUIDE TO THE STUDY OF LICHENS. 
 
 medium, usually marginal, margin not raised. Disk 
 convex, reddish-brown. Spores colorless, four-celled, 
 oblong, elliptical, granular contents, 30yu X 7^. 
 
 This rather rare and highly interesting lichen has 
 been found in the New England States and in Cali- 
 fornia. 
 
 Jf.. Mallotium. 
 
 The thallus of this genus indicates a higher develop- 
 ment than Leptogium ; it is thicker and larger ; it fre- 
 quently bears soralia or soredia ; its cortical tissues are 
 more highly developed. Color is dark-blue. The 
 lower surface bears numerous very long delicate rhi- 
 zoids. The algee are JVostoc. 
 
 The apothecia are similar to those of Collema and 
 Leptogium. As a rule, the few representatives which 
 occur in the United States are found to be sterile. 
 
 They occur upon trees and rocks, and range from 
 north to south, though they are quite rare. Generally 
 Mallotium is classed with Leptogium. As a genus it 
 requires further study. 
 
 1. Mallotium saturninum. Thallus large, quite 
 thick, nearly monophyllous, margin lobate ; upper sur- 
 face granular, dull gray to dark-blue ; lower surface 
 bearing long, slender, grayish rhizoids. Apothecia not 
 
 seen. 
 
 IX. PANNARIACE^. 
 
 Considerable uncertainty exists as to the limitations 
 of this family ; genera are included which seem to have 
 no possible genetic relationship to other genera {Ephehe, 
 Lichina). The algal-characters vary greatly, and have 
 been made the basis of the generic determination. The 
 
GENERA AND SPECIES. 185 
 
 characters of the thalhis also vary greatly ; the smaller 
 and more insignificant forms are fruticose ; the higher 
 forms are foliose. This seems to be contradictory to 
 the arrangement of the Parmeliacece, in which family 
 the fruticose forms are placed highest. Upon close 
 examination it is, however, very evident that the fruti- 
 cose forms of the Pannariacece are very lowly organ- 
 ized as lichens. 
 
 The algae of this family are blue-green, with the ex- 
 ception of those of Psoroma and Sticta in which genera 
 they are bright-green. As regards spore-characters, 
 the only thing that can be stated here is that none are 
 multilocular and that th^y are not very large ; most of 
 them are colorless. The apothecial-characters are as 
 variable as the thallus-characters. 
 
 KEY TO THE GENERA. 
 
 Symbiotic algae {Sirosiphon) forming the 
 bulk of the thallus-structure of 
 minute brandling filaments , . 1. Ephehe. 
 Symbiotic algae (not Sirosiphon) not form- 
 ing the bulk of the thallus struc- 
 ture. 
 
 Thallus crustose, dark 2. Lecofhecium. 
 
 Thallus fruticose, dark, minute. 
 
 Cortical tissue \v;vnting, spores simple. 
 
 Algae in chains {Rivularia) . . . . 3. Lichina. 
 
 Algae singly ( Gloeocapsa) 4. Omphalaria. 
 
 Cortical tissue present, spores two- 
 celled, colorless 5. Polychidium. 
 
 Thallus folio«e. 
 
 Spores simple, colorless. 
 Apothecia innate in depression of 
 
 thallus 6. Heppia. 
 
 Apothecia discoid, sessile. 
 Algae singly, bright -green {Proto- 
 
 coccus) 7. Psoroma. 
 
 Algae in colonies, blue-green (Poly- 
 coccus) , . . . . S. Pannaria. 
 
186 GUIDE TO THE STUDY OF LICHENS. 
 
 Spores not simple. 
 Apothecia innate upon upper surface 
 of thallus. 
 Spores acicular, 4-6 celled, colorless 9. Peltigera. 
 Spores two-celled, elliptical, brown 10. Solo'rina. 
 Apothecia innate upon lower surface 
 
 of upturned lobes 11. Nephromium. 
 
 Apothecia discoid, sessile, spores acic- 
 ular, 4-6 celled. 
 Algae blue-green (Polycoccus) . . 12. Stictina. 
 Algae bright-green (Protococcus) . 13. Sticta. 
 
 1. Ephehe. 
 
 This genus evidently does not belong to this family 
 since it has nothing in common with the other genera. 
 The thallus is very minute, fruticose and dark in color. 
 It consists of an alga {Sirosiphon pulvinatus) which is 
 branching and through which the hyphas of the fungal 
 symbiont ramify. In that respect it is highly different 
 from any other lichen-group ; that is the alga forms 
 the supporting and protecting structure while the 
 fungus is the protected symbiont. 
 
 The Ephehes occur upon rock in moist places. It 
 is in most instances very difficult to decide whether 
 the plant be Ephehe or the alga Sirosiphon pulvinatusj 
 which is exactly similar in form and in its habitat. 
 Very frequently the plant bears spermagonia which at 
 once proves it lichen-nature. I am even of the 
 opinion that the spermagonia are the fungal sym- 
 bionts ; these appear as semi-translucent swellings 
 along the side of the branches. A good pocket- 
 lens is necessary to make out the structure of the 
 Ephehes. 
 
 1. Ephehe puhescens. Thallus minute, much 
 branched, rigid when dry, more or less decumbent, 
 
GENERA AND SPECIES. 187 
 
 dark to nearly black. Spermagonia sometimes numer- 
 ous. 
 
 Considerable material from widely different localities 
 has been examined, but no apothecia have been found. 
 It is perhaps always sterile in this country. Lindsay 
 and others report it as apothecia-bearing in Europe. 
 Bornet, the noted French lichenologist, states that it 
 is dioeciaus, that is, the male reproductive organs (sper- 
 magonia) occur upon one plant, while the female or- 
 gans (apothecia) occur upon another plant. It seems 
 to be an undecided question whether Ephehe puhescens 
 is a genuine lichen ; it is perhaps only an alga (^S. pul- 
 vinatus) parasitically associated with fungi (sperma- 
 gonia and apothecia). 
 
 Tuckerman reports two more species, E. mammiUo- 
 sum and E. solida, both of which are said to resemble 
 the one described. 
 
 2. Lecothecium. 
 
 Thallus crustose to perhaps minutely foliose, dark, 
 closely adnate to substratum. The algoe are bluish- 
 green and occur in chains {Rivularia nitida). 
 
 The apothecia are of medium size, discoid, sessile or 
 partially immersed. The hypothecium is usually dark, 
 sometimes blue-black. The spores are few, variable 
 in size and form, due to the fact that but few attain 
 maturity. Wlien mature they are oblong, colorless, 
 four-celled. 
 
 Only a few representatives are known in this coun- 
 try, they occur in the arctic regions and the north 
 temperate zone. They grow upon rock or sandy 
 soil. 
 
188 GUIDE TO THE STUDY OF LICHENS. 
 
 1. Lecothecium nigrum. Thallus crustose, granular, 
 indistinctly areolate, nearly black. Apothecia small, 
 somewhat raised above the thallus. Disk black. Spores 
 oblong, colorless, indistinctly once to thrice septate, 
 bearing oil-droplets, 13/x X 5/i,. 
 
 This lichen is also known as Collema nigrum. It 
 forms inky-black stains upon the rock on which it 
 grows. 
 
 2. Lecothecium corallinoides. Thallus crustose to 
 minutely scaly, scales ascending, dark-brown. Apo- 
 thecia sessile, somewhat immersed. Disk flattened, 
 dark-brown. Spores few, elliptical, 14/x X '^/w,. 
 
 This species is generally described as Pannaria 
 
 microphyllum. 
 
 3. Lichina. 
 
 Thallus crustose, minute, branching, dark, some- 
 what resembling that of Ephehe, but differs in that the 
 fungal symbiont forms the greater bulk of the struct- 
 ure and the protective tissue. The algse are Rivularia 
 nitida, hence blue-green and in chains. No cortical tis- 
 sue is present. 
 
 The apothecia are small, terminal, globose, appear- 
 ing as small nodular enlargements of the ends of some 
 branches. They are dark. Spores are simple, ellipti- 
 cal, colorless. The hypothecium is colorless. 
 
 Only a few species are known, they occur upon 
 rock in moist places and are found in the tropics 
 as well AS in the far north. 
 
 1. Lichina conjinis. Thallus minute, branching, 
 lobes rigid and erect, dark. Apothecia terminal, 
 globose, dark. Spores colorless, simple, elliptical. 
 
GENERA AND SPECIES. 
 
 189 
 
 ^. Omphalaria. 
 
 Thallus small, fruticose, lobes flattened, dark. The 
 apothecia are terminal, nearly globose, dark. In fact 
 the genus closely resembles Lichina. The algal sym- 
 biont varies, however. Upon close examination it 
 will be found that the predominating alga is single 
 celled, with a thick, colorless, gelatinous covering, and 
 is evidently Glceocapsa polydermatica. Nostoc is, how- 
 ever, also present, at least in most specimens. 
 
 The spores are simple, colorless, elliptical ; again 
 they are evidently septate. They occur upon rock in 
 the temperate and arctic zones. The genus requires 
 
 further study. 
 
 1. Omphalaria umhella, Thallus small, attached 
 by an umbilicus, branching, lobes flattened and crenu- 
 late, dark to nearly black. Apothecia terminal, 
 globose to discoid. Disk brown. Spores simple, 
 colorless, elliptical, 18/w, X 7.5^. 
 
 5. Polychidium. 
 
 Thallus small, fruticose, branching, lobes cylindrical, 
 dark. There is a cortical tissue present, thus distin- 
 guishing the genus from the genera already described. 
 The algfe are evidently Rivularia or modified Nostoc. 
 The general gross characters of the thallus resemble 
 those of Ephehe. 
 
 The apothecia are small, discoid, and sessile upon 
 the basal portion of the thallus. Disk brown and 
 hypothecium colorless. The spores are oblong, ellipti- 
 cal or spindle-shaped to somewhat curved, two-celled, 
 colorless. This genus also requires further careful 
 
190 GUIDE TO THE STUDY OF LICHENS. 
 
 study; at present it is generally included under Lepto- 
 gium. 
 
 1, Polychidium muscicolum. Tliallus small, fruti- 
 cose, much branched, lobes cylindrical, dark to olive- 
 black. Apothecia medium, discoid upon the older 
 basal branches. Disk flattened to concave, brown. 
 Spores typical of the genus, 25;a X 8/x. 
 
 This lichen is found growing over moss, on rocks, 
 and occurs at great altitudes. It frequently occurs on 
 high rocks facing the ocean. 
 
 6. Heppia. 
 
 Thallus of medium size, foliose,- monophyllous, 
 closely adnate to the substratum ; margin more or less 
 lobed ; brown color, becoming quite dark with age. 
 Rhizoids numerous. The algse are perhaps a species 
 of Scytonema. 
 
 The apothecia are comparatively large, innate in 
 concave depressions of the thallus, a characteristic not 
 occurring in any other lichen-genus. The hypothecium 
 is colorless. Disk reddish-brown. Spores are colorless, 
 simple, thin-walled with granular contents, and vari- 
 able in size and form. 
 
 1. Heppia Despreuxii. Thallus foliose, monophyl- 
 lous, margin lobate, closely adherent to substratum, 
 dark. Apothecia typical of the genus. Spores typical, 
 22/t X 9/^. 
 
 There is perhaps only one authentic species in exist- 
 ence. The European specimens labelled H. urceolata 
 and H. adglutinata are in all respects similar. H. 
 Despreuxii is southern and occurs upon sandy soil. 
 
GENERA AND SPECIES. 191 
 
 7. Psoroma. 
 
 Thallus foliose, branching, lying flat over substra- 
 tum. The alga3 are Protococcus. It is perhaps prob- 
 able that this genus is phylogenetically derived from 
 Pannaria which genus it resembles in all but the algal 
 characters. 
 
 Apothecia discoid, margin irregular. Disk reddish- 
 brown. Spores colorless, simple, spindle-shaped. 
 
 1. Psoroma hypnorum. Thallus consisting of as- 
 cending scales which are more or less lobed, reddish- 
 brown. Apothecia medium to large, margin crenulate 
 and bearing thalloid outgrowths. Disk reddish-brown. 
 Spores typical, 13.5/x X 9/w- 
 
 2. Psoroma stellata. Thallus of imbricate, many 
 cleft, ascending lobes with crenate margin, pale brown 
 above ; whitish beneath with numerous rhizoids. Apo- 
 thecia few, small to medium, sessile. Disk convex, 
 pale brown to reddish-brown. Spores rare, not seen. 
 
 8. Pannaria. 
 
 Thallus foliose, lobed and usually of a reddish-brown 
 color above, pale beneath. The lower forms, however, 
 approach the crustose type. The alga? are blue-green 
 in color, and occur in groups (^Poly coccus punctiformis). 
 The apothecia are usually quite small, discoid, sessile. 
 Disk flattened, with margin somewhat raised, reddish- 
 brown ; hypothecium colorless. The spores resemble 
 those of the preceding genus. 
 
 The genus is somewhat southern in its range ; the 
 species occur upon moss, soil, rock and trees. At present 
 
192 GUIDE TO THE STUDY OF LICHENS. 
 
 considerable confusion exists as to the limitations of 
 the genus. 
 
 i. Pannaria hrunnea. Thallus from coarsely warty 
 to minutely foliose, tawny-brown. Apothecia medium, 
 margin rugose, warty. Disk flattened to concave, red- 
 dish-brown. Spores simple, colorless, granular, ends 
 pointed, 18/x X 9/><" 
 
 2. Pannaria lepidiota. Thallus of small closely 
 adnate or sometimes ascending lobes, branching, warty 
 and more or less crenate, brown to dark-brown. Apo- 
 thecia small, margin crenate. Disk flattened, reddish- 
 brown to dark-brown. Spores simple or apparently two- 
 celled, contents granular, oblong elliptical, 15/x X 6/x,. 
 
 3. Pannaria leucosticta. Thallus foliose, adnate, 
 lobed, much divided and more or less ascending, mar- 
 gin whitish ; greenish-gray above, dirty gray beneath. 
 Apothecia small, margin crenulate. Disk convex, 
 reddish-brown. Spores simple, colorless, enclosed by 
 a spindle-shaped gelatinous mass, 12/x X 6/i. 
 
 4- Pannaria luridum. Thallus quite large, lobed, 
 brown to bluish-brown above ; light-gray to bluish-gray 
 beneath, with numerous dark rhizoids. Apothecia 
 small, margin almost entire. Disk convex, pale chest- 
 nut to dark. Spores simple, colorless, spheroidal to 
 spindle-shaped, spore-wall warty, 10.5/x X 8/x. 
 
 This lichen is often classed as Physma luridum. 
 
 5. Pannaria ruhiginosa. Thallus much branched, 
 margin faintly white ; brown above, dark beneath. 
 Apothecia rather small, margin crenate. Disk con- 
 vex, reddish-brown. Spores spheroidal, spore-wall 
 comparatively thick, 13/x X 10/** 
 
GENERA AND SPECIES. 193 
 
 6. Pannaria molybdcea. Thallus large, mostly en- 
 tire, margin lobed, gray to bluish-gray • light-gray 
 to yellowish beneath with gray rhizoids. Apo- 
 thecia variable in size. Disk convex, irregular in 
 outline, pale chestnut changing to nearly black. 
 Spores simple or indistinctly two-celled, colorless, 
 spindle-shaped, 11^ X 4.5/x. 
 
 9. Peltigera. 
 
 Thallus large, lobes rounded and large. As a rule 
 the thallus is quite thick and rigid but not brittle. 
 Color above is generally bright blue-green, which 
 promptly changes to brown on drying ; the lower sur- 
 face is light-brown and bears large simple and branch- 
 ing rhizoids. 
 
 Upon examining a vertical section of the thallus it 
 is found that no lower cortical tissue is present, as one 
 would expect in so large a plant. The algae are blue- 
 green, as in Pannaria {Poly coccus punctiformis) . 
 
 The apothecia are quite large and are innate upon 
 the upper margin or terminal upon special lobes. In 
 outline the apothecia are orbicular to somewhat oval. 
 The spores are acicular, colorless, three to five-septate, 
 usually somewhat curved. 
 
 The range of the species is northern, though some 
 occur south. They grow upon rock, more commonly 
 upon soil in forest lands among mosses, also at the 
 basal portions of tree-trunks. They do not thrive in 
 open, exposed places. 
 
 1. Peltigera apthosa. Thallus large, lobes broad, 
 upper surface sprinkled with flattened brown warts, 
 
194 GUIDE TO THE STUDY OF LICHENS. 
 
 bluish-green above ; pale and reticulate beneath, with 
 comparatively few large rhizoids. Apothecia medium, 
 marginal on large lobes. Disk reddish-brown. Spores 
 typical, 65/A X 6/a. 
 
 Some of the uses of this lichen have already been 
 referred to elsewhere. According to Willemet, it was 
 an excellent vermifuge when given in doses of twelve 
 grains, evening and morning, during six or eight days. 
 It was also said to possess emetic properties. 
 
 2. Peltigera canina. Thallus large, lobes large, 
 rounded, greenish-gray and smooth above ; beneath 
 paler and reticulate with whitish rhizoids. Apothecia 
 medium to large, marginal. Disk reddish-brown. 
 Spores acicular, three to five-septate, 65/a X^/x. 
 
 This is the lichen which obtained such renown as a 
 remedy for the cure of hydrophobia. It was also con- 
 sidered to have diuretic properties. 
 
 3. Peltigera polydactyla. Thallus large, smooth 
 above, greenish to brown ; beneath reticulate with com- 
 paratively few rhizoids. Apothecia medium, terminal 
 on narrowed thallus-lobes. Spores typical. 
 
 10. Solorina. 
 
 The thallus is quite large, foliose, rigid, and re- 
 sembles the thallus of the foregoing in that the lower 
 cortical layer is wanting. It is loosely attached to 
 the substratum by long rhizoids. The upper surface 
 is smooth and brown in color ; the lower surface is 
 light-brown to brick-red {S. croced). Two forms of 
 algae are present; one bright-green {Dactylococcus), 
 the other blue-green i^Poly coccus). 
 
GENERA AND SPECIES. 195 
 
 The apothecia resemble those of Peltigera ; the disk 
 is brown to dark-brown. The spores are elliptical, 
 two-celled and brown in color. 
 
 The Solorinas are northern in their range, occurring 
 among moss, upon rock and soil. 
 
 1. Solorina crocea. Thallus rather small, not dis- 
 tinctly branching, closely adnate to substratum ; brown 
 above, orange-red beneath, with darker veins. Apo- 
 thecia medium to large. Disk reddish-brown. Spores 
 typical of genus, 50/x, X 20/a. 
 
 2. Solorina saccata. Thallus thinner than in S. 
 croceay paler. Apothecia medium, in depressions of 
 the thallus. Spores typical, 50/tx X 20/x. 
 
 11. Nephromium. 
 
 The thallus of Nephromium has a distinct, well- 
 developed Ibwer cortical layer, from the lower surface 
 of which extend long rhizoids. In other respects the 
 thallus resembles that of the Peltigeras. (The algae 
 are blue-green and occur in colonies as in Peltigera.') 
 
 The apothecia are more or less oval or kidney-shaped 
 and are marginal upon the lower surface of upturned 
 lobes, a character not found in any other lichen-group. 
 The disk is reddish-brown. The spores vary from 
 nearly acicular to oval, usually four-celled and brown. 
 
 Some species have bright-green algte (Protococcus), 
 and should be classed with another genus {Nephroma). 
 
 The species are northern in their range, and occur 
 upon rock and tree-trunks in shaded places. 
 
 i. Nephromium*l(Evigatum. Tliallus medium, lobes 
 rather small, rounded, undulate, brown above; paler 
 
196 GUIDE TO TFIE STUDY OP LICHENS. 
 
 beneath and somewhat reticulate. Apothecia medium. 
 Disk reddish-brown. Spores fusiform-elliptical, brown, 
 20/x X 6/i. 
 
 2. Nephromium Lusitanicum. Thallus medium, 
 lobes deeply cut, sinnate, margin crenate, dark-brown ; 
 the interior appears yellowish. Apothecia and spores 
 mufeh as in N. Icevigatum. 
 
 3. Nephromium Helveticum. Thallus medium, lobes 
 rather narrowed, undulate, smooth above gray to 
 tawny ; dark beneath. Apothecia medium. Disk dark. 
 Spores as in N. Icevigatum. 
 
 4' Nephromium tomentosum. Thallus large, lobes 
 rounded, undulate and crenate margin, gray to reddish- 
 brown above ; paler beneath. Apothecia medium. Disk 
 reddish-brown. Spores much as in N Icevigatum. 
 
 12. Stictina. » 
 
 Most authors combine Stictina with Sticta, but ow- 
 ing to distinct algal differences we have kept them 
 separate. 
 
 The thallus is large, lobed, medium in thickness and 
 brittleness. It reminds one somewhat of Parmelia 
 and Physcia. The lobes usually lie flat upon the sub- 
 stratum and are rather loosely attached by rhizoids. 
 Color is generally dark-brown tinged with bluish-green. 
 The algae are blue-green and occur in colonies (as in 
 Pannaria and Peltigerd). 
 
 There is a morphological character by means of 
 which one may recognize most of the representa- 
 tives of Stictina as well as Sticta, and that is the 
 occurrence of cyphellae upon the lower surface. (See 
 
GENERA AND SPECIES. 197 
 
 Cyphella.) There are, however, exceptions (Sticta 
 amplissima, S. pulmonaria, and several others). 
 
 The apothecia are rather small, discoid, sessile. 
 Disk slightly concave, flattened to slightly convex. 
 Spores colorless, oblong to acicular, four-celled. 
 
 The species are southern in their range, they occur 
 upon trees and rocks. 
 
 1. Stictina tomentosa. Thai! us medium, deeply 
 lobed, pitted above and bluish-brown, paler beneath, 
 with white cyphella3 and rhizoids. Apothecia medium, 
 scattered, sometimes marginal. Disk reddish-brown 
 to dark. Spores typical, 4o/a X 10/u,. 
 
 2. Stictina quercizans. Thallus rather large, lobes 
 rounded and somewhat imbricate, sinuate and crenate, 
 dark-brown above; rhizoids and white cyphella? be- 
 neath. Apothecia rare, medium. Disk dark-brown. 
 Spores typical. 
 
 There are a considerable number of species, but 
 none have marked distinctive characters. The ama- 
 teur will perhaps be satisfied to give the plants col- 
 lected their generic position. In fact, by doing so 
 he will do no small part toward defining the limitations 
 of the two genera. Further study may show that the 
 Stictinas and Stictas devoid of cyphellce do not belong 
 
 here. 
 
 13. Sticta. 
 
 Thallus in all respects similar to that of Stictina. 
 Color less dark and less tinged with blue, owing to 
 the fact that the algaj are briglit-green {Profococ- 
 cus). 
 
 The apothecial and spore-characters are similar. 
 
198 GUIDE TO THE STUDY OF LICHENS. 
 
 Considerable variation has been noted in the apo- 
 thecial characters of some Stictas which leads to the 
 conclusion that some of the apothecia may be the fruc- 
 tification of a fungal parasite closely related to Arthonia. 
 Particularly has this been observed in S. pulmonaria. 
 Further careful research is necessary to determine the 
 parasites living upon lichens. Let us hope that some 
 of the amateurs for whom this book is written may 
 make observations and studies which will aid in clear- 
 ing up some of these mysteries. 
 
 The Stictas are less distinctively southern in their 
 range. The change in algal symbiont may have en- 
 abled the plants to thrive in a colder climate. They 
 occur upon rocks and trees. 
 
 1. Sticta amplissima. Thallus large, parmelioid, 
 rather thin and papery, lobed, grayish-green and 
 smooth above ; brown beneath, with rhizoids but no 
 cyphellae. Apothecia rather large, numerous. Disk 
 chestnut-brown. Spores colorless, long, slender, some- 
 what curved, indistinctly septate, 46/x X 6/x. 
 
 2. Sticta pulmonaria. Thallus large, lobes long, 
 upper surface divided into concave areas, ridges and 
 margin lined with soralia, dirty brown tinged with 
 bluish-green ; lower surface of convex areas light- 
 brown, no cyphellae. Apothecia few, medium. Disk 
 reddish-brown to dark. Spores very closely resemble 
 those of Arthonia, 18/x X 5.5/x. 
 
 This lichen quite generally occurs at the base ot 
 trees (weather-side) at high altitudes. It is usually 
 isolated, and the entire plant has the appearance of 
 being decrepit and old, so that upon seeing it for the 
 
I'LATK II. Folinst' Types, tliallus nearly I'liiin-. \, Sticta 
 jiuliitoHKrid. tr.iiii Mt. Tanialpais, .Marin ("it., ("alifornia. 
 .'», i'liiliiliairia jtustulata, from California Aeadeuiy of 
 Science. 
 
GENERA AND SPECIES. 199 
 
 first time one is likely to pass it by hoping to find a 
 "better" specimen. 
 
 " This lichen was at one time much prized as a 
 remedial agent and in the dyeing industry. Its specific 
 name as well as its familiar desis^nation 'luniks of oak' 
 or * tree lungwort ' is due either to its efficacy, real or 
 supposed, in pulmonary affections, as a nutrient, de- 
 mtflcent or tonic; or from a fancied resemblance be- 
 tween the reticulate character of the thallus and the 
 mesh-like structure of lungs. The Swedish peasantry 
 were wont to employ it in epidemic catarrh of cattle, 
 especially of sheep ; and in Germany, probably for 
 similar purposes, it was given to cattle mixed with 
 salt." — Lindsay. 
 
 Library 
 
LICHENES IMPERFECTI OR FALSE LICHENS. 
 
 Formerly various lichens and parts of lichens were 
 classed as Pseudolichens or Lichenes imperfecti. Of 
 these six generic groups were recognized: Isidium 
 Ach., Variolaria Ach., Lepra Hall., Pulveraria Ach., 
 Spilonema Ach., Pyrenothea Fr. Isidium included 
 the peculiar warty and isidioid outgrowths quite fre- 
 quent on the upper surface of foliose thalli ; it also 
 comprised various sterile warty crustose lichens. Un- 
 der Variolaria were included sterile forms of Pertusa- 
 ria communis, P. lactea, besides other sterile crustose 
 lichens of a gray or whitish color, especially those 
 bearing numerous soredia. Lepra included the pseudo- 
 lichen L. viridis as well as sterile forms of Placodium 
 and perhaps Rinodina. Under Pulveraria were evi- 
 dently included incipient primary thalli of Cladonia 
 as well as sterile forms of Calicium, etc. The char- 
 acters of Spilonema are very uncertain, referring, per- 
 haps, to sterile forms of Graphis, Arthonia, etc. The 
 term Pyrenothea referred, no doubt, to low forms of 
 lichens (perhaps old, dying plants) bearing numerous 
 8permagonia, pycnidia, or perhaps parasitic fungi. 
 
THE CONTINENTAL RANGE OF THE MORE IM- 
 PORTANT LICHEN GENERA OCCURRING 
 IN THE UNITED STATES. 
 
 The following table gives the general continental 
 range of the lichen-genera represented in the United 
 States. Some of the genera are not sufficiently known 
 to indicate their true range; such are marked with 
 an *. Those given under *' U. S." are perhaps about 
 uniformly distributed in the United States. 
 
 Northern 
 
 Southern 
 
 Eastern 
 
 Western 
 
 U.S. 
 
 [ros 
 Sphseropho- 
 
 Pilophoron 
 Stereocaulon 
 Cladoiiia 
 Thamnolia 
 
 Biatorella* 
 Bilimbia* 
 
 Buellia 
 
 Catillaria* 
 
 Megalospora* 
 
 Gyrophora 
 Umbilicaria 
 
 BsBomyces 
 
 Bacidia 
 Lopadinm 
 
 Caliciacex 
 Mycocalici- 
 
 [um* 
 
 Cyphelium 
 Cladoniaceee 
 
 Lecideacese 
 Graphidacese 
 
 
 Coniocybe* 
 Calicium 
 Cyphelium 
 Acolium 
 
 Biatorella* 
 Biatorina* 
 Biatora 
 Bilimbia 
 
 Lecidea* 
 
 Celidiopsis* 
 
 Buelliopsis* 
 
 Gyaleota 
 Psora 
 
RANGE OF LICHENS IN THE INITED STATES. 203 
 
 Northern Soatbern 
 
 Eastern 
 
 Western 
 
 U.S. 
 
 Hazslinskya* 
 
 Opegrapha 
 Graphis 
 Xylographa 
 Arthonia 
 Mycoporura 
 Arthotheli- 
 [um 
 
 Placodiuin 
 Pyxine 
 
 Physciacess 
 
 Rinodina 
 Placodium 
 
 Hazslinskya 
 
 Rinodina 
 
 Pyxine* 
 Physcia 
 
 
 Physcia 
 
 
 
 
 Theloschistes 
 
 Parmeliacese 
 
 
 
 Urceolaria 
 
 " 
 
 
 
 
 Haematomma 
 
 
 
 
 Lecanora 
 
 
 [dera 
 Speerschnei- 
 
 
 [dera 
 Speerschnei- 
 
 Acarospora 
 Parraelia 
 
 Cetraria 
 
 Ramalina 
 
 
 Evernia 
 Ramalina 
 
 
 Alectoria 
 
 
 
 
 
 Bryopogon 
 
 [um 
 Trypetheli- 
 Pyrenuia 
 
 Thelotrema 
 Gyros torn um 
 Verrucaria* 
 
 [cex 
 Verrucaria. 
 
 1 
 
 
 Usnea 
 
 Conotrema 
 Verrucaria 
 
 Pertusaria 
 
 Dermatocar- 
 
 
 
 Pertusaria 
 
 
 [pon 
 
 Collemaceae 
 Pannariacese 
 
 Hydrothyria* 
 
 Endocarpon 
 
 Collenia 
 Leptogi um 
 Maliotiura 
 Hydroihyria* 
 
 Lecothecium 
 
 
 
 
 Ephebe 
 Lecothecium 
 
 Omphalaria 
 Polychidium 
 
 
 
 
 Licliina 
 Omphalaria 
 
 Psoroma* 
 
 Eleppia 
 Pannaria 
 
 
 
 
 Solorina 
 
 
 
 
 Peltigera 
 
 Nephron) ium 
 
 Stictina 
 
 
 
 
 Sticta J 
 
 sticta i 
 
 Sticta 
 
 
LIST OF LICHENS OCCURRING IN THE UNITED 
 STATES. 
 
 This list is by no means complete. It is, in fact, at 
 present impossible to give the exact number of species 
 occurring within the territory indicated. Willey be- 
 lieves that ultimately one thousand species will be 
 found. No authentic list can be compiled until the 
 existing species have been carefully determined. It is 
 very probable that a considerable number of lichens 
 have been described as distinct species which are in 
 reality one and the same species ; particularly is this 
 true of the lower forms. 
 
 The list gives some idea of tho number of species 
 occurring in the various genera, and will be found of 
 great value to those who wish to make exchanges or 
 who wish to build up a fairly complete lichen-herba- 
 rium. 
 
 The families are given in their natural order, while 
 the genera and species are given in alphabetical order. 
 This arrangement in alphabetical order is simply for 
 convenience of reference. The list gives about 1,250 
 species and varieties ; of these, no doubt a consider- 
 able number are synonyms. Furthermore, there are 
 a few doubtful genera and species which have been en- 
 tirely omitted. It is highly probable that there are 
 not more than 1,200 authentic species and varieties of 
 lichens in the United States. 
 
CALICIACE^. CLADONIACE^. 
 
 205 
 
 I. Caliclaceee 
 
 J. Acolium 
 
 Bolanderi 
 
 Californicura 
 
 Carolinianum 
 
 chloroconium 
 
 Hawaiiense 
 
 Javanicum 
 
 leucampyx 
 
 stigonela 
 
 Sti. Jacobi 
 
 tympanella 
 
 viridula 
 
 S. Acrocyphus 
 
 sphasrophoroides 
 
 S. Calicium 
 
 albo-nigrum 
 
 brunneolum 
 
 byssaceum 
 
 chrysocephalum 
 
 citrinum 
 
 Curtisii 
 
 curtum 
 
 disseminatum 
 
 eusporum 
 
 facultatum 
 
 fucipes 
 
 hyperellum 
 
 lenticulare 
 
 leucochlorum 
 
 leucopodum 
 
 melanophaeum 
 
 microcephalum 
 
 parietinum 
 
 phaeocephalum 
 
 polyporajum 
 
 praecedens 
 puUatulum 
 quercinurn 
 Ravenelii 
 roscidum 
 subcinereum 
 subtile 
 trachelium 
 trichiale 
 tubaeforme 
 turbinatum 
 4- Coniocybe. 
 albella 
 furfuracea 
 pallida 
 
 5. Mi/cocalicium 
 
 Curtisii 
 fucipes 
 
 6. Pyrgillus 
 
 Araericanus 
 
 7. Sphcerophorus 
 
 compressus 
 coralloides 
 fragilis 
 
 8. Sphinctrina 
 
 anglica 
 
 leucopoda 
 
 turbinata 
 
 II. Cladonlaces 
 
 1. Bccomyces 
 absolutus 
 ffiruginosa 
 byssoides 
 fungoides 
 placopliyllus 
 roseus 
 
206 
 
 CLADONIACEiE. 
 
 S. Cladonia 
 alcicomis 
 amaurocraea 
 bellidiflora 
 Boryi 
 botrytis 
 caespiticia 
 cariosa 
 carneola 
 
 cyanipes 
 cenotea 
 
 furcellata 
 ceratophylla 
 cornucopioides 
 cornuta 
 cristatella 
 
 ramosa 
 dactylota 
 decorticata 
 deformis 
 degenerans 
 delicata 
 digitata 
 Dilleniana 
 endiviafolia* 
 fimbriata 
 
 tubseformis 
 
 radiata 
 Floerkeana 
 furcata 
 
 a. crispata 
 
 h. ramosa 
 
 c. subulata 
 
 d. pungens 
 
 e. racemosa 
 gracilenta 
 gracilis 
 
 a. verticilata 
 * cervicornis 
 
 ** sy mphy carpia 
 
 b. hybrida 
 
 c. elongata 
 hypoxantha 
 leporina 
 macilenta 
 mitrula 
 papillaria 
 pulcliella 
 pyxidata 
 
 b. pocillum 
 rangiferina 
 
 b. sylvatica 
 
 c. alpestris 
 Ravenelii 
 santensis 
 sympliycarpa 
 
 6. epiphylla 
 squamosa 
 turgida 
 
 b. conspicua 
 uncialis 
 
 3. Endogene 
 informis 
 4- Pilophoron 
 cereolus 
 a. fibula 
 6. Hallii 
 
 c. aucicularis 
 
 d. robustus 
 5. Siphula 
 
 ceratites 
 dactyliza 
 Pickeringii 
 Ramalinoides 
 
CLADONIACEiE. — LECIDIACK^E. 
 
 20: 
 
 cornuta 
 simplex 
 subtabularis 
 6. Stcreocdulon 
 albicans 
 alpestre 
 clavipes 
 coiidensatum 
 coralloides 
 (lemulatum 
 maderense 
 nahodes 
 paschale 
 piliatum 
 pilophoroides 
 proxinum 
 ramulosum 
 
 vimineum 
 Wriffhtii 
 tomentosuin 
 
 b. Alpinum 
 7. Thamnolia 
 
 vermicularis 
 
 a. subuliformit 
 
 b. taurica 
 
 III. Lecidiacese 
 
 1. Bacidia 
 
 alborussula 
 
 atrogrisea 
 
 atrosanguinea 
 
 Beckliausii 
 
 chloraniha 
 
 cUlorosticta 
 
 effusa 
 
 b. arcontina 
 fusco-rubella 
 
 incompta 
 inundata 
 rnedialis 
 raicTophyllina 
 millegrana 
 nmscoruni 
 rubella 
 rufescens 
 Schweinitzii 
 stigniatella 
 subabbrevians 
 suffusa 
 unibrian 
 2. B I at or a 
 aenea 
 
 anthrocophila 
 apochroeiza 
 atro-rufa 
 aurigera 
 carnulenta 
 cinnabarina 
 circumflexa 
 
 coarotata 
 
 b. Brugeriana 
 
 cuprea 
 
 denotata 
 
 Uiapensia) 
 
 ementiens 
 
 exigiia 
 
 flavido-liviens 
 
 flexuosa 
 
 furfuracca 
 
 furfurosa 
 
 fuscescens 
 
 glebulosa 
 
 granulosa 
 
 hypouiela 
 
208 
 
 LECIDIACE^. 
 
 inspersabilis 
 
 internectans 
 
 Konyamensis 
 
 leucophaea 
 
 lucida 
 
 mutabilis 
 
 myriocarpoides 
 
 Nylanderi 
 
 oxyspora 
 
 parvifolia 
 
 b. subgranuloea 
 
 c. corallina 
 peliaspis 
 peliaspistes 
 punctella 
 pycnotheliza 
 quernea 
 rivulosa 
 
 b. mollis 
 rubidula 
 rufo-fusca 
 rufo-fuscella 
 russula 
 
 sanguineo-atra 
 spurococca 
 subdeusta 
 Torneonsis 
 turgidula 
 uliginosa 
 varians 
 vernalis 
 viridescens 
 b. gelatinosa 
 S. BiatoreUa 
 campestris 
 cyphalea 
 fossarum 
 
 geophana 
 ilicis 
 
 moriformis 
 resinae 
 4- Biatorina 
 
 atro-purpurea 
 
 curaulata 
 
 cyrtella 
 
 denigrata 
 
 erysibe 
 
 expallescens 
 
 glauconigrans 
 
 globulosa 
 
 gyalizella 
 
 Heerii 
 
 lutea 
 
 micrococca 
 
 mixta 
 
 pineti 
 
 prasina 
 5. Bilimbia 
 
 allinita 
 
 artyta 
 
 caudata 
 
 cupreo-rosella 
 
 declinis 
 
 Friesiana 
 
 hyaliniza 
 
 hypnophila 
 
 leucoblephara 
 
 melaena 
 
 milliaria 
 
 Nagelii 
 
 obscurata 
 
 pallidella 
 
 parasitula 
 
 sphaeroides 
 
LECIDIACE^. 
 
 209 
 
 suballinita 
 
 subfuscula 
 
 trachona 
 
 tricholoma 
 
 trisepta 
 
 verecunda 
 6. Buellia 
 
 Africana 
 
 albo-atra 
 
 b. saxicola 
 allothallina 
 alpicola 
 amphidextra 
 atro-albescens 
 attendenda 
 badia 
 badio-atra 
 bolacina 
 Bolanderi 
 calcarea 
 Caloosensis 
 catasema 
 Catawbensis 
 coUudens 
 coracina 
 decinerascens 
 destitula 
 dialyta 
 Eliza 
 epigea 
 geographica 
 
 b. lecanorina 
 glauconiaria 
 glaucomarioides 
 halonia 
 ignobile 
 infernula 
 
 inquilina 
 
 Japonica 
 
 lactea 
 
 lepidastra 
 
 leptocline 
 
 leucosepha 
 
 meiosperma 
 
 myriocarpa 
 
 b. polyspora 
 minimula 
 ochrodela 
 Oderi 
 oidalea 
 pappillata 
 parasenia 
 parasitica 
 parasitula 
 parmeliarura 
 pertusaricola 
 petraea 
 
 b. grandis 
 
 c. Montagnaei 
 
 d. albinae 
 praebadia 
 pulchella 
 pullata 
 Ravenelii 
 retrovertens 
 Rittokensis 
 saxatilis 
 scabrosa 
 Schaereri 
 Semitensis 
 seinotula 
 Smithii 
 spuria 
 squamulata 
 
210 
 
 LECIDIACE^. 
 
 stellulata 
 
 vellea 
 
 stigmsea 
 
 12. Lecidea 
 
 trypethelia 
 
 acclinis 
 
 turgescens 
 
 aglam 
 
 urceolata 
 
 aglasida 
 
 vilis 
 
 albocoerulescens 
 
 7. BuelUopsis 
 
 h. flaA'ocoerulescens 
 
 platycarpa 
 
 alpestris 
 
 8. Cattillaria 
 
 amylacea 
 
 grossum 
 
 arctica 
 
 9. Celidiopsis 
 
 b. pallida 
 
 vernicoma 
 
 Armeniaca 
 
 10. Gyalecta 
 
 aromatica 
 
 carneo-luteola 
 
 assimilata 
 
 cupularis 
 
 atrobrunnea 
 
 faxicola 
 
 auriculata 
 
 riotovii 
 
 diducens 
 
 Friesii 
 
 Brandegeei 
 
 geoica 
 
 borealis 
 
 * trivialis 
 
 brachyspora 
 
 lutea 
 
 Candida 
 
 nana 
 
 caudata 
 
 pineti 
 
 cceruleonigricans 
 
 rhexoblephara 
 
 conferenda 
 
 Valenqueliana 
 
 confluens 
 
 11. Gyrophora 
 
 contigua 
 
 anthracina 
 
 h. hydrophila 
 
 h. reticulata 
 
 crassipes 
 
 Dillenii 
 
 cruciarea 
 
 erosa 
 
 crytidia 
 
 flocculosa 
 
 cumulata 
 
 hirsuta 
 
 dendroclinis 
 
 hyperborea 
 
 dispecta 
 
 Miihlenbergii 
 
 elata 
 
 polyphylla 
 
 enteroleuca 
 
 proboscidea 
 
 h. theioplaca 
 
 6. arctica 
 
 c. equata 
 
LECIDIACEiE. 
 
 211 
 
 d. muscorum 
 €. achrista 
 /. flavida 
 g. ambigua 
 
 epiiodiza 
 
 erratica 
 
 flavovirescens 
 
 fusco-atra 
 
 fusco-cinerea 
 
 glaucospora 
 
 granosa 
 
 insularis 
 
 lapicida 
 
 Laurentiana 
 
 limosa 
 
 lugubrior 
 
 lugubris 
 
 lygotropa 
 
 mamillana 
 
 Manni 
 
 massata 
 
 melanoheima 
 
 melapsepha 
 
 monticola 
 
 micytho 
 
 neglecta 
 
 pallida 
 
 panocola 
 
 paraphana 
 
 parasitica 
 
 paupercula 
 
 planetica 
 
 platy carpa 
 
 polycarpa 
 
 Pringlei 
 
 pruniosa 
 
 psephota 
 
 pycnocarpa 
 
 Rhajtica 
 
 ruginosa 
 
 scrobiculata 
 
 Simodensis 
 
 sporostatia 
 
 apeiorea 
 
 squalida 
 
 subliraosa 
 
 subtristisinscula 
 
 sylvicola 
 
 tenebrosa 
 
 tessellata 
 
 tessellina 
 
 ultima 
 
 variegata 
 
 viiellinaria 
 
 vorticosa 
 13. Lopadium 
 
 pezizoideum 
 
 vulpinum 
 14- Afegalospora 
 
 porphyrites 
 
 sanguinaria 
 15. Psora 
 
 anthracophila 
 
 atro-rufa 
 
 caulophylla 
 
 crenata 
 
 decipiens 
 
 Friesii 
 
 glob if era 
 
 b. rubiformis 
 
 icteria 
 
 luridella 
 
 ostreata 
 
 Petri 
 
212 
 
 LECIDIACKiE. 
 
 GRAPHIDACE^. 
 
 rufo-nigra 
 
 Russellii 
 
 scotopholis 
 
 16. Sporastatia 
 
 morio 
 6. coracina 
 
 17. Toninia 
 
 aclinis 
 
 caudata 
 
 flavovirescens 
 
 granosa 
 
 massata 
 
 ruginosa 
 
 squalida 
 
 18. Umbillcaria 
 
 Pennsylvanica 
 pustulata 
 h. papulosa 
 
 IV. Qraphidacese 
 
 1. Arthonia 
 
 abrothallina 
 albofuscescens 
 astericus 
 •astroidea 
 
 swartzoidea 
 atrata 
 carneo-rufa 
 caudata 
 chiodectella 
 cinnabarina 
 conturbata 
 cupressina 
 cyrtodes 
 diffusa 
 dispersa , 
 Eekfeldtii 
 
 epipastoides 
 
 erubescens 
 
 erupta 
 
 excedens 
 
 exilis 
 
 fissurinea 
 
 Floridana 
 
 glaucescena 
 
 glebosa 
 
 gregaria 
 
 gregarina 
 
 hamamelidis 
 
 Hibernica 
 
 impallens 
 
 impolita 
 
 chiodectiodes 
 incarnata 
 lapidicola 
 lecideella 
 leucastraea 
 lurida 
 lurido-alba 
 mediella 
 melaspora 
 ochrolutea 
 opegraphina 
 oxytera 
 palmicola 
 paralia 
 
 platygraphidea 
 platyspeila 
 polymorpha 
 punctiforrais 
 phyrrhula 
 phyrrhuliza 
 quintaria 
 radiata 
 
(JKAl'HIDACK^:, 
 
 213 
 
 ramulosa 
 
 Kavenelii 
 
 reneformis 
 
 rubella 
 
 saiiguinoa 
 
 subastroidella 
 
 subcyrtodes 
 
 subminutissima 
 
 subniinutula 
 
 subpalliduscula 
 
 subrubella 
 
 taedescens 
 
 tagdiosa 
 
 terigena 
 
 varia 
 
 varians 
 
 velata 
 
 vernans 
 
 violascens 
 subcinerascens 
 
 Xylographica 
 S. Arthothelium 
 
 interveniens 
 
 macrotheca 
 
 mesoleuca 
 
 spectabile 
 S. Gli/phis 
 
 Achariana 
 
 labyrintliica 
 4' Graphis 
 
 Afzelii 
 
 assirailis 
 
 Babingtonii 
 
 botryosa 
 
 eolumbina 
 
 conietia 
 
 dendritica 
 
 discurrens 
 
 Dumaslii 
 
 elegans 
 
 erumpens 
 
 eulectra 
 
 Floridana 
 
 glaucoderma 
 
 haematites 
 
 hololeucoides 
 
 hypoleptella 
 
 intricans 
 
 inusta 
 
 leiogrammodes 
 
 leprocarpa 
 
 leucocephola 
 
 leucopepla 
 
 Mosquitensis 
 
 nitida 
 
 nitidella 
 
 nitidesceiM 
 
 oscitans 
 
 patellula 
 
 Pavoniana 
 
 Poitaeoides 
 
 punctiformis 
 
 radiata ^ 
 
 rigida 
 
 rufula 
 
 scalpturata 
 
 scolecites 
 
 scripta 
 
 linitata 
 
 recta 
 
 serpentina 
 
 varia 
 sophistica 
 striatula 
 
214 
 
 ^ 
 
 GRAI'HIDACK^. 
 
 PHYSCIACE^. 
 
 
 subnitidula 
 
 ciliaris 
 
 
 substriatula 
 
 b. crinalis 
 
 
 tricosa 
 
 comosa 
 
 5 
 
 HazUnszkya 
 
 crispa 
 
 
 demissa 
 
 dilatata 
 
 6. 
 
 Opegrapha 
 
 integrata 
 
 
 astraea 
 
 erinacea 
 
 
 atra 
 
 granulifera 
 
 
 hapalea 
 
 hispida 
 
 
 Bonplandi 
 
 hypoleuca 
 
 
 levidensis 
 
 hypomela 
 
 
 microcyclia 
 
 Leana 
 
 
 notha 
 
 leucomela 
 
 
 oalochila 
 
 major 
 
 
 prosodea 
 
 obscura 
 
 
 quaternella 
 
 pulverulenta 
 
 
 riraalis 
 
 b. leucoleiptes 
 
 
 tribulodes 
 
 Ravenelii 
 
 
 varia 
 
 setosa 
 
 
 viridis 
 
 speciosa 
 
 
 vulgata 
 
 stellaris 
 
 
 lithyrga 
 
 6. aipolia 
 
 7. 
 
 Xylographa 
 
 tribacea 
 
 
 disseminata 
 
 Wrightii 
 
 
 hians 
 
 3. Placodium 
 
 
 •pegraphella 
 
 aurantiacum 
 
 
 parallela 
 
 cerinum 
 6. sideritis 
 
 
 V. Physciaceae 
 
 c. pyracea 
 
 1. 
 
 Dimelcena 
 
 cinnabarinum 
 
 
 oreina 
 
 cirrochroum 
 
 2. 
 
 Physcia 
 
 citrinum 
 
 
 adglutinata 
 
 cladodes 
 
 
 aquila 
 
 comptidium 
 
 
 b. detonsa 
 
 coralloides 
 
 
 astroidea 
 
 crenatellum 
 
 
 ceasia 
 
 elegans 
 
PHYSCIACK^. 
 
 PARMELIACE^. 
 
 215 
 
 erythranthum 
 eupyrmn 
 fcrnitrineum 
 h. Pallinii 
 
 c. discolor 
 
 d. Wright ii 
 ferruginosum 
 Floridanum 
 fulgens 
 
 b. bracteatum 
 galactophyllum 
 Jungerraanniae 
 luteorninium 
 microphyllum 
 murorum 
 nivale 
 Faumotense 
 peliophyllum 
 phaeum 
 rupestre 
 sinapispemum 
 spadiceura 
 Spraguei 
 variabile 
 
 b. atro-album 
 vitellinum 
 
 b. aurellum 
 
 4. Pi/xine 
 
 cocoes 
 
 Frostii 
 
 Meissneri 
 
 picta 
 
 sorediata 
 
 5. Rinodina 
 
 ascocisoana 
 
 aterrima 
 
 Bishoffi 
 
 chrysomelaena 
 
 Conradi 
 
 constans 
 
 flavonigella 
 
 Hallii 
 
 maniillana 
 
 niilliaria 
 
 nimbosa 
 
 ochrotis 
 
 radiata 
 
 sophodcs 
 
 b. atrocinera 
 
 c. tephraspis 
 
 d. confragosa 
 
 e. exigua 
 Thorn ae 
 thysanota 
 turfaceae 
 
 6. roscida 
 
 c. mniaraea 
 6. Thelochistes 
 
 crysophthalmus 
 
 b. flavicans 
 concolor 
 
 b. effusa 
 flavicans 
 lychneus 
 parietinus 
 polycarpus 
 ramulosus 
 
 VI. Parmeliaceie 
 
 1. Ahctoria 
 Fremontii 
 Japonica 
 
 (I. bicolor 
 
 6. chalvlti'ifDrmis 
 
216 
 
 > PARMELIACE^. 
 
 c. iniplexa 
 
 odontella 
 
 Loxensis 
 
 platyphylla 
 
 nitulifera 
 
 ramulosa 
 
 ochroleuca 
 
 Richardsoma 
 
 a. rigida 
 
 saepincola 
 
 * asteina 
 
 b. chlorophylla 
 
 ** nigrescens 
 
 tristis 
 
 b. cincinnata 
 
 4' Conotrema 
 
 c. sarmentosa 
 
 urceolatum 
 
 £. Bryopogon 
 
 5. Evernia 
 
 Oregana 
 
 divaricata 
 
 jubata 
 
 furfuracea 
 
 S. Cetraria 
 
 b. cladonia 
 
 aculeata 
 
 prunastri 
 
 aleurites 
 
 trulla 
 
 h. placardia 
 
 vulpina 
 
 arctica 
 
 6. Gt/rostomum 
 
 aurescens 
 
 scyphuliferum 
 
 Califomica 
 
 7. Hcematoma 
 
 chrysantha 
 
 achrophaea 
 
 ciliaris 
 
 clatina 
 
 cucullata 
 
 Hageni 
 
 Fahlunensis 
 
 punicea 
 
 Fendleri 
 
 ventosa 
 
 glauca 
 
 8. Lecanora 
 
 b. stenophylla 
 
 acarospora 
 
 Islandica 
 
 b. pruniosa 
 
 b. Delisaei 
 
 c. Clavus 
 
 juniperina 
 
 d. revertens 
 
 h. terrestris 
 
 athrocarpa 
 
 c. pinastri 
 
 atra 
 
 lacunosa 
 
 atriseda 
 
 b. stenophylla 
 
 Bockii 
 
 madreporiformis 
 
 badia 
 
 nigricans 
 
 calcarea 
 
 nivalis 
 
 b. contorta 
 
 Oakesiana 
 
 Cenisia 
 
PARMKLIACKiE. 
 
 217 
 
 cervina 
 
 b. Tliamnina 
 cinerea 
 
 b. lasvata 
 
 c. gibbosa 
 cupressi 
 epulotica 
 
 b. subpulotica 
 frustulosa 
 fuscata 
 
 6. rufescens 
 gelida 
 glaiicocarpa 
 
 b. verrucosa 
 Haydeni 
 lacustris 
 lentigera 
 miculata 
 raolybdina 
 niurialis 
 
 a. saxicola 
 
 b. Garovaglii 
 
 c. diffracta 
 
 d. semitensis 
 €. versicolor 
 
 odora 
 pallescens 
 
 b. rosella 
 pallida 
 
 b. cancriformis 
 
 c. angulosa 
 rubina 
 
 b. heteromorpha 
 
 c. opaca 
 sordida 
 subfusca 
 
 a. allophana 
 
 b. hypnoruin 
 
 c. argentata 
 
 d. coilocarj)a 
 
 e. distans 
 tartarea 
 varia 
 
 b. polytropa 
 
 c. intricata 
 
 d. symmicta 
 
 e. saepincola 
 verrucosa 
 
 b. mutabilis 
 virens 
 vitellina 
 Willeyi 
 xanthophana 
 9. Mi/coporum 
 
 pycnocarpum 
 10. Parmelia 
 ambigua 
 
 b. albescens 
 
 c. Halli 
 aurulenta 
 Borreri 
 
 b. rudecti 
 
 c. hypomela 
 caperata 
 centrifuga 
 cervicornis 
 cetrata 
 colpodes 
 conspersa 
 crinita 
 cyclocelis 
 encausta 
 
 b. alpicola 
 flavicans 
 
218 
 
 PARMELIACE^. 
 
 glomulifera 
 hypoleuca 
 incurva 
 
 Japonica [icana 
 
 Kamtschadalis Amer- 
 laevigata 
 lanata 
 lattissima 
 leucochlora 
 lophyraea 
 molliuscula 
 olivacea 
 *aspidota 
 
 b. prolixa 
 
 * pannif ornis 
 
 c. soridiata 
 perforata 
 
 * hypotropa 
 perlata 
 pertusa 
 physodes 
 
 b. obscurata 
 
 c. enteromorpha 
 
 d. vittata 
 placardia 
 revoluta 
 saxatilis 
 
 b. sulcata 
 
 c. panniformis 
 
 d. amphalodes 
 speciosa 
 subrugata 
 sulphurata 
 stygia 
 Texana 
 tiliacea 
 
 b. subleavijijata 
 
 c. relicina 
 
 d. sulphurosa 
 11. Pertusaria 
 
 albinea 
 
 ambigens 
 
 bryontha 
 
 coccophora 
 
 colobina 
 
 communis 
 
 concreta 
 
 dactylina 
 
 euglypta 
 
 flavicunda 
 
 globularis 
 
 glomerata 
 
 lactea 
 
 lecanina 
 
 leioplaca 
 
 multipuncta 
 
 panyrga 
 
 pertusa 
 
 pustulata 
 
 rhodocarpa 
 
 velata 
 
 Wulfenii 
 
 12. Phlyctis 
 
 subtile 
 
 13. Ramalina « 
 
 calicaris 
 a. fraxinea 
 6. fastigiata 
 
 c. canaliculata 
 
 d. farinaeea 
 ceruchis 
 complanata 
 crinita 
 dasypoga 
 
U- 
 
 15. 
 
 PARMKLIACE^. 
 
 denticulata 
 
 leucastrum 
 
 *canalicularis 
 
 lirelliforme 
 
 honialea 
 
 microcarpum 
 
 leavigata 
 
 monosporum 
 
 linearis 
 
 myrioporum 
 
 Manni 
 
 piluliferum 
 
 Menziesii 
 
 platycarpoides 
 
 poUinarella 
 
 platycarpum 
 
 pollinaria 
 
 postpositum 
 
 polyinorpha 
 
 Ravenelii 
 
 pusilla 
 
 Santense 
 
 b. geniculata 
 
 simplex 
 
 reticulata 
 
 subtile 
 
 rigida 
 
 Wightii 
 
 Montagnaei 
 
 Wrightii 
 
 scopulorum 
 
 16 Urceolaria 
 
 stenospora 
 
 actinostoma 
 
 usneoides 
 
 chloroleuca 
 
 Speerschneidera 
 
 cinerea 
 
 euploca 
 
 scruposa 
 
 Thelotrema 
 
 17. Usnea 
 
 actinotuni 
 
 angulata 
 
 Auberianum 
 
 barbata 
 
 auratum 
 
 a. Florida 
 
 catastictum 
 
 c. dasypoga 
 
 Cubanum 
 
 d. plicata 
 
 Domingense 
 
 e. articulata 
 
 glaucescens 
 
 cavernosa 
 
 granulosum 
 
 ceratina 
 
 interpositum 
 
 hirta 
 
 lathraeum 
 
 longissima 
 
 latilabrum 
 
 mollis 
 
 leiostonium 
 
 rubiginea 
 
 lepadium 
 
 strigosa 
 
 lepadodes 
 
 sulphurea 
 
 leprocarpum 
 
 trichodea 
 
 219 
 
220 
 
 VERRUCARIACE^. 
 
 VII. Verrucariaces 
 
 1. Dermatocarpon 
 
 pusillum 
 f. Endocarpon 
 
 arboreum 
 
 cinereum 
 
 fluviatile 
 
 hepaticum 
 
 Manitense 
 
 miniatum 
 complicatum 
 fulvofuscum 
 aquaticum 
 
 Moulinsii 
 
 Miihlenbergii 
 
 ochroleucura 
 
 pallidum 
 
 pusillum 
 
 rufescens 
 
 tephroides 
 
 Texanura 
 3. Pyrenula 
 
 aggregata 
 
 aspistea 
 
 aurantiaca 
 
 cinchonae 
 
 fallaciosa 
 
 fetivica 
 
 geminella 
 
 gemmata 
 
 glabrata 
 
 hyalospora 
 
 lactea 
 
 leucochlora 
 
 leucoplaca 
 
 mamillana 
 
 nitida 
 
 oblongata 
 
 ochraceo-flava 
 
 pachycheila 
 
 punctiforrais 
 
 quinque-septata 
 
 rhyponta 
 
 subcinerea 
 
 subprostans 
 
 thelaena 
 
 thelomorpha 
 
 tropica 
 
 4- Tri/pethelium 
 aggregata 
 catervarium 
 cruentum 
 Eleuteriae 
 exocanthum 
 Kunzei 
 
 madrepiforme 
 mastoideum 
 megaspermum 
 ochroleucum 
 pallescens 
 pyrenuloides 
 scorites 
 tropica 
 uberinoides 
 virens 
 
 S Verrucaria 
 
 centhocarpa 
 
 consequella 
 
 dermoplaca 
 
 epigaea 
 
 fuscella 
 
 glabrata 
 
 margacea 
 
 maura 
 
VERRUCARIACKiE. COLLEMACEA:. 
 
 221 
 
 microbola 
 
 mucosa 
 
 mnralis 
 
 nigresccns 
 
 papillosa 
 
 pinguicola 
 
 prospersella 
 
 punctiforrais 
 
 ruderella 
 
 rupestris 
 
 purpurascens 
 Sprucei 
 striatula 
 tartaricola 
 umbrina 
 virens 
 viridula 
 
 VIII. Collemacese 
 
 1. Col I e ma 
 
 aggregatum 
 
 callebotris 
 
 cladodes 
 
 cocophorum 
 
 crispum 
 
 cristatellum 
 
 cristatum 
 
 cyrtaspis 
 
 flaccidum 
 
 furvum 
 
 glaucophthalnium 
 
 granosuin 
 
 laciniatuni 
 
 leptalt'um 
 
 limosum 
 
 melainum 
 
 microphyllum 
 
 microptychium 
 multipartitum 
 myriococcum 
 nigrescens 
 
 b. leucopepla 
 plicatile 
 piilposum 
 pustulatum 
 pycnocarpum 
 ryssoleum 
 stellatum 
 stenopliyllum 
 ten ax 
 Texanum 
 verruciforme 
 
 2. Hydrothyria 
 
 venosa 
 
 3. Leptofjitnn 
 
 adpressum 
 apalachense 
 bolacinum 
 bullatum 
 Burgessii 
 caesiellum 
 Californicum 
 chloromelum 
 a. conchatum 
 h. stellaris 
 corniculatum 
 crenatcllum 
 dactylinum 
 dendriscum 
 hypotracliinum 
 iiiflexuni 
 intricatulum 
 juniperinum 
 lacerum 
 
COLLEMACE^. PANNARIACE^E. 
 
 marginellura 
 minutissium 
 palmatum 
 phyllocarpum 
 insidiosum 
 macrocarpum 
 pulchellum 
 rivale 
 sinuatum 
 tenuissimum 
 tremelloides 
 4' Mallotium 
 
 albociliatum 
 myochroum 
 saturninum 
 
 IX. Pannariacese 
 
 1. Ephehe 
 
 maramillosum 
 
 Lesquereuxii 
 
 pubescens 
 
 solida 
 f . Heppia 
 
 arenivaga 
 
 Despreuxii 
 
 Guepii 
 
 polyspora 
 
 virescens 
 S. Lecothecium 
 
 corallinoides 
 
 nigrum 
 
 4. Lichina 
 
 confinis 
 
 * Willeyi 
 
 pygmea 
 
 5. Nephromium^ 
 
 articura 
 
 cxpallidum 
 Helveticuni 
 leavigatum 
 h. parile 
 Lusitanicum 
 subleavigatum 
 tomentosum 
 
 6. Omphalaria 
 
 Cubana 
 
 deusta 
 
 Gerardi 
 
 leptophylla 
 
 lingulata 
 
 phyllisca 
 
 pulvinata 
 
 pyrenoides 
 
 symphorea 
 
 Texana 
 
 Wrightii 
 
 7. Polychidium 
 
 muscicolum 
 
 8. Pannaria 
 
 brunnea 
 
 byssina 
 
 carnosa 
 
 crassophylla 
 
 flabellosa 
 
 glaucella 
 
 grannatina 
 
 Hookeri 
 
 hypnorum 
 
 lanuginosa 
 
 lepidiota 
 
 leucosticta 
 
 lurida 
 
 melamphylla 
 
 microphylla 
 
PANNARIACE^:. 
 
 223 
 
 molybdaea 
 
 b. cronia 
 
 c. incisa 
 nigrocincta 
 pannosa 
 Petersii 
 pholidota 
 placodopsis 
 plumbea 
 rubiginosa 
 
 b. conoplea 
 Sonomensis 
 stellata 
 stenophylla 
 symptychia 
 tryptophylla 
 9. Pel tiger a 
 aphthosa 
 canina 
 
 b. spongiosa 
 
 c. membranacL'ii 
 horizontalis 
 malacea 
 polydactyla 
 pulverulenta 
 rufescens 
 scutata 
 
 venosa 
 10. Psoroma 
 
 hypnorum 
 stellata 
 
 11. Solorina 
 
 crocea 
 
 saccata 
 
 spongiosa 
 
 12. Sticta 
 
 amplissima 
 
 anthraspis 
 
 aurata 
 
 damaecornis 
 
 dissecta 
 
 erosa 
 
 herbacea 
 
 glomulifera 
 
 pallida 
 
 pulmonaria 
 /'. hypomela 
 c. linita 
 
 13. Stlctina 
 
 crocata 
 
 fuliginosa 
 
 Hallii 
 
 Huraboldtii 
 
 limbata 
 
 Oregana 
 
 Pickeringi 
 
 quercizans 
 
 scrobiculata 
 
 sylvatica 
 
 tomentosa 
 
 Wrightii 
 
GENERAL INDEX. 
 
 Acarospora, 152 
 
 cervina, 152 
 
 dealbata, 153 
 
 privigna, 152 
 Accessory structures, 48 
 Acharius, 1, 6 
 Acids, 37 
 - action of, 18 
 Acoliuni, 85 
 
 tigillare, 85 
 Adaptations, mutual, 53 
 Aerial alg£B, 33 
 Affinity, double, 33 
 Affinity of lichens, 11 
 Africa, 3, 19 
 Agardh, 7 
 Agassiz, 149 
 Alaska, 20 
 Alcohol, 24 
 Alectoria, 165 
 
 ochroleuca, 165 
 
 sarmentosa, 165 
 Algse, 25 
 Algal layer, 43 
 Algeria, 19 
 Alps, 149 
 Altrnism, 31 
 Altruistic, 18 
 Analogy, 40 
 Andes, 111 
 Antberidia, 11 
 Apr>thecia, 46 
 Arabia, 3 
 
 Arthonia, 128 
 astroidea, 129 
 atra, 131 
 dispersa, 129 
 glabrata, 130 
 lecideellft> 130 
 polymorpha, 130 
 punctiformis, 130 
 quintaria, 130 
 radiata, 130 
 tsediosa, 130 
 varia, 131 
 
 Arthothelium, 132 
 spectabile, 132 
 
 Artificial key, 77 
 
 Asci, 28 
 
 Ascomycetes, 28 
 
 Assimilation, 26 
 
 Association, 31 
 
 Autonomy, 14 
 
 Bacidia, 109 
 
 albescens, 109 
 atrogrisea, 110 
 chlorosticta, 109 
 cuprea-rosella, 109 
 iuundata, 110 
 rubella. 110 
 Schweinitzii, 110 
 sufifusca, 110 
 
 Bacteria, 26, 27 
 
 BsBomyres, 87 
 seruginosus, 89 
 
226 
 
 GENERAL INDEX. 
 
 Baeomyces. 
 
 byssoides, 89 
 
 roseus, 88 
 Baranetzky, 13 
 Basidia, 28 
 Basidospores, 28 
 Beard-moBS, 23, 168 
 Beer, 24, 168 
 Bertram, 168 
 Biatora, 105 
 
 cinnabarina, 107 
 
 contigua, 106 
 
 dlapensisB, 106 
 
 granulosa, 107 
 
 myriocarpoides, 106 
 
 parvifolia, 107 
 
 peliaspis, 107 
 
 russula, 107 
 
 uliginosa, 106 
 
 varians, 105 
 
 vernalis, 107 
 Biatorella, 104 
 
 geophaiia, 104 
 Biatorina, 104 
 
 lutea. 104 
 
 pineti, 105 
 Bilimbia, 108 
 
 hypnophila, 108 
 
 mixta, 108 
 
 sphaeroides, 108 
 Bitter principle, 20 
 Blotting-paper, 66 
 Bornet, 13, 187 
 Brewing, 24 
 Brittleness, 57 
 Bryopogon, 166 
 
 jubata, 166 
 
 Oregana, 166 
 Bucke, 101 
 Buellia, 112 
 
 badia, 114 
 
 colludeus, 114 
 
 coracina, 114 
 
 dialyta, 113 
 
 Elizae, 114 
 
 Buellia. 
 
 myriocarpa, 114 
 
 Parmeliarum,113 
 
 parasema, 113 
 
 pulchella, 115 
 
 Schaereri, 113 
 
 spuria, 115 
 
 stellulata, 114 
 Buelliopsis, 112 
 
 vernicoma, 112 
 
 CaesHlpinus, 4 
 Caliciacese, 81 
 Calicium, 83 
 
 Curtisii, 83 
 
 f uscipes, 83 
 
 byperellum, 83 
 
 lenticulare, 83 
 
 quercinum, 84 
 Calkins, 144 
 Camex'arius, 4 
 Canada, 20 
 Canary Islands, 21 
 Canary rock-moss, 157 
 Candelaria, 143 
 Cape Verde Islands, 2^ 
 Carbon dioxide, 32 
 Catillaria, 115 
 
 grossa, 115 
 Cave dwellings, 19 
 Celidiopsis, 112 
 
 platycarpa, 112 
 Centric, 40 
 Cephalodia, 50 
 Cetraria, 157 
 
 ciliaris, 158 
 
 cucullata, 159 
 
 Fahlunensis, 158 
 
 Islandica, 19, 159 
 
 juniperina, 158 
 
 lacunosa, 159 
 Cbeese, manufacture of, 27 
 Cbilblains, 161 
 (Jbloropbyoeae, 34 
 Chloropbyll, 26, 27 
 
GENKRAL INDEX. 
 
 227 
 
 Chroolepus umbriua, 34 
 Cladonia, 92 
 
 alclcoruis, 96 
 
 aiuaurocraja, 100 
 
 bellidiflora, 97 
 
 cseapiticia, 94 
 
 cariosa, 95 
 
 ceuotea, 96 
 
 cornucopioldes, 97 
 
 cristatella, 95 
 
 decorticata, 95 
 
 deformis, 97 
 
 delicata, 94 
 
 digitata, 98 
 
 timbriata, 98 
 
 furcata, 99 
 
 gracilis, 98 
 
 lepidota, 96 
 
 leporina, 100 
 
 luacileuta, 95 
 
 mitrula, 94 
 
 papillaria, 93 
 
 pulchella, 94 
 
 pyxidata, 96 
 
 rangiferiua, 19, 100 
 
 squamosa, 99 
 
 symphycarpa, 94 
 
 turgida, 99 
 
 micialis, 99 
 
 verticillata, 98 
 Cladoniacese, 87 
 Classiticatiou, 73 
 
 methoda of, 75 
 Cold, 36 
 
 Collecting-box, 58 
 Collection of lichens, 56 
 Collema, 179 
 
 crispum, 182 
 
 cyrtaspis, 180 
 
 tiacciduiu, 182 
 
 laciuiatutu, 181 
 
 leucopepla, 181 
 
 limosum, 8 
 
 myriococcuni, 181 
 
 nigrescens, 181 
 
 Collema. 
 
 plicatile, 182 
 
 pulposmu, 181 
 
 pycnocaipuHj, 180 
 
 ryssoleum, 181 
 ColleraacesB, 179 
 Color, restoration of, 63 
 Couiocybe, 82 
 
 furfuracea, 82 
 
 pallida, 82 
 Conotrema, 171 
 
 urceolatum, 172 
 Cousortism, 12 
 Cora, 28 
 
 Cortical layer, 42 
 Cortical tissue, 47 
 Crabbe, 100 
 Crab's-eye lichen, 150 
 Crombie, 12 
 Crottle, 150, 156 
 Crystals, acid, 43 
 Cudbear, 22 
 Cyanophyceai, 35 
 Cyphelium, 84 
 
 tubseforme, 84 
 
 turbinatum, 84 
 Jyphell*, 49, 196 
 Cystococcus bumicola, 34 
 
 Dactylococcus, 35 
 Darbishire, 14 
 Dark crottle, 156 
 De Bary, 12 
 De Candolle, A. P., 6 
 De Notaris, 2 
 Dermatocarpon, 17t 
 
 pusillum, 177 
 Dilleu, 5 
 Dioecious, 187 
 Dioscorides, 3,21, 23 
 Disintegration of rock, 17 
 Disk, 126 
 Dog-lichen, 23 
 Dropsy, 168 
 Dryers, 66 
 
228 
 
 GENERAL INDEX. 
 
 Dye, 21 
 Dyeing, 20 
 
 Earth-bread, 19 
 
 Elepliautiasis, 20 
 
 Endlicher, 7 
 
 Endocarpon, 177 
 arbox-eum, 178 
 fluviatile, 178 
 hepaticum, 178 
 iniuiatuni, 178 
 
 Evernia, 163 
 
 f urf uracea, 3, 1()4 
 vulpina, 22, 164 
 
 Evolution, 39 
 
 Ephebe, 186 
 
 maniminosuru, 187 
 pubescens, 186 
 solida, 187 
 
 Epidermis, 40 
 
 Epilepsy, 23 
 
 Eschweiler, 7 
 
 Esenbeck, Nees von, 8 
 
 Excrescences, 56 
 
 Exine, 86 
 
 Exosporium, 86 
 
 Exodus, 19 
 
 Ezekiel, 21 
 
 Fabr ictus, 23 
 Fairies, 156 
 Fairy rings, 49, 154 
 False lichens, 200 
 Famintzin, 13 
 Faveoli, 17 
 Federigo, 21 
 F6e,7 
 
 Feld-elfln, 156 
 Female organs, 11 
 Fermentation, 26 
 Fevers, 23 
 Food-substances, 26 
 
 inorganic, 26 
 
 organic, 27 
 France, 22, 150 
 
 Franklin, 20, 121 
 Freezing, 36 
 Fries, 7, 10 
 Function, loss of, 27 
 
 mechanical, 31 
 
 of lichens, 17 
 Fungal type, 40 
 Fungi, 26 
 
 spores of, 37 
 
 Generation, spontaneous, 7, 9 
 Georgi, 6 
 Germany, 10 
 Gessner, 3 
 Glass, 23 
 
 Gloeocapsa, 35, 189 
 Glueing, 67 
 Gonidia, 9, 11 
 Graphidaceai, 124 
 Graphis, 127 
 
 dentritica, 127 
 
 elegans, 127 
 
 eulectra, 127 
 
 scripta, 127 
 Green mould, 30 
 Green substance, 8 
 Gyalecta, 117 
 
 cupularis, 117 
 Gyrostomum, 172 
 
 scyphuliferum, 173 
 Gyrophora, 119 
 
 Dillenii, 122 
 
 erosa, 121 
 
 floculosa, 121 
 
 hyperborea, 120 
 
 Miihlenbergii, 121 
 
 proboscidea, 120 
 
 vellea, 121 
 
 Hsematomma, 146 
 
 ochrophjea, 147 
 
 punicea, 147 
 
 ventosa, 147 
 Hair-powders, 23 
 Haustoria, 41 
 
GENERAL INDEX. 
 
 229 
 
 Huzslinskya 125, 
 deniissa, 126 
 gibberuloaa, 126 
 
 Hedwig, C 
 
 Hemaus, Mrs., 97 
 
 Heppia, 190 
 
 adglutinata, 190 
 Deapreuxii, 190 
 urceolata, 19(» 
 
 Herbarium, 65 
 
 Heterocysts,35 
 
 Heterotbecium, 116 
 
 Himalayas, 111 
 
 History, 1 
 
 Horse-tail, lichen, 166 
 
 Hii^, 12, 52 
 
 Humboldt, 168 
 
 Hydrophobia, 23 
 
 Hydrothyria, 183 
 veuosa, 183 
 
 Hypothallus, 133 
 
 Hysterium, 34 
 
 Icelaud, 20 
 Icelaud moss, 19, 159 
 Iceland scurvy, 20 
 Idle moss, 168 
 Individualisni, 31 
 Insects, 44 
 Iodine reaction, 19 
 Ireland, 155 
 Isidiuni, 200 
 Isle of Man, 155 
 Isolateral, 40 
 Israelites, 19 
 Italy, 3, 21 
 Itzigsohn, 11 
 
 Jaundice, 23, 159 
 Jumelle, 13 
 
 Key, artificial, 77 
 
 natural, 80 
 Keys, 76 
 Korber, 10 
 
 Krempelhuber, 1 
 
 Labelling, 69 
 Lamarck, 7 
 I^af,37,40 
 Ijecanora, 148 
 
 atra, 150 
 
 Bockii, 149 
 
 calcaria, 149 
 
 cenisia, 151 
 
 Cupressi, 149 
 
 esculenta, 19 
 
 Hageni, 149 
 
 lacustris, 148 
 
 muralis, 151 
 
 orosthea, 148 
 
 pallescens, 150 
 « pallida, 149 
 
 r.ubina, 151 
 
 subfusca, 150 
 
 tartarea, 151 
 
 varia, 149 
 Lecidea, 110 
 
 enteroleuca. 111 
 
 geographicH, 111 
 
 melancheima, 111 
 
 panaeola, 111 
 Lecideaceae, 102 
 Lecothecium, 187 
 
 corallinoides, 188 
 
 nigrum, 188 
 Ledges, 01 
 Leighton, 12 
 Lepra, 200 
 
 viridis, 200 
 Leptogium, 182 
 
 chloromeluni, 183 
 Lichen-alga?, 37 
 Licheu-starch, 19, 37 
 Lichen-tundra, 52 
 Lichenes im perfect i, 2(X) 
 Licheniu, 19» 37 
 Lichenology, history oi, 1 
 Lichens, altltudinal range, 62 
 
 autonomy of, 14 
 
230 
 
 GENERAL INDEX. 
 
 Licbeus. 
 
 cleauiug of, 66 
 
 collection of, 56 
 
 contiueutal rauge of, 202 
 
 distribution of, 52 
 
 economic value of, 18 
 
 false, 200 
 
 function of, 17 
 
 latitudinal range of, 52 
 
 list of, 204 
 
 morpbology of, 39 
 
 naming of, 68 
 
 occurrence of, 52 
 
 origin of, 25, 29 
 
 pbysiology of, 39 
 
 preservation of, 65 
 
 relation to algse, 33 
 
 relation to fungi, 33 
 
 sets of, 65 
 
 spores of, 37 
 
 study of, 63 
 
 uses of, 16 
 Licbina, 188 
 
 confinis, 188 
 Lindau, 14 
 Liudley, 7 
 Lindsay, 11 
 Linn^, 5, 16, 124 
 Litmus. 22 
 Liverworts, 7 
 Lopadium, 116 
 
 pezizoideum, 117 
 Lungs of oak, 199 
 Lungwort, 199 
 
 Male organs, 11 
 Mallotium, 184 
 
 saturninum, 184 
 Malpbigi, 4 
 Manna, 19 
 Massalonga, 10 
 Mead, Dr., 23 
 Medullary layer, 43 
 Medullary tissue, 47 
 Megalospora, 116 
 
 Megalospora. 
 
 sanguinaria, 116 
 Metamorpbosis, 9 
 Meyer, 2, 8 
 Micbeli, 1, 4 
 Microcosnios, 36 
 Micrometer, 82 
 Micron, 82 
 Microscope, 9, 64 
 Moisture, 62 
 Monstrosities, 16 
 Morison , 4 
 Morpbology, 39 
 Mosses, 4, 5 
 Mould, 26 
 
 Mounting sbeets, 67 
 Mucor, 83 
 Mudd, 10 
 Mummies, 3 
 Mycoporum, 131 
 
 pycnocarpuni, 131 
 
 Nageli, 11 
 Natural key, 80 
 Neoformations, 50 
 Nepbromium, 195 
 Helveticum, 196 
 Icevigatum, 195 
 Lusitanicum, 196 
 tomentosum, 196 
 Nostoe licbenoides, 35 
 Nostoc muscorura, 8 
 Note-book, 62 
 Nova Zembla, 111 
 Nux vpmica, 23 
 Nylander, 10, 52 
 
 Okeu, 7 
 Ompbalaria, 189 
 
 umbella, 189 
 Opegrapba, 126 
 
 varia, 126 
 
 vulgata, 126 
 Orcbella-weed, 22 
 Orcbill, 22 
 
GENERAL INDEX. 
 
 231 
 
 Organs, female, 11 
 
 male, 11 
 Orjcellarii, 21 
 Orseille, 22, 150 
 
 Pannaria, 191 
 
 bruniiea, 192 
 
 lepidota, 192 
 
 leucosticta, 192 
 
 luridum, 192 
 
 molybdasa, 193 
 
 rubigiuosa, 192 
 Pannariaceae, 184 
 Paper, manufacture of, 24 
 Paraphyses, 47 
 Parasitism, 12, 27 
 Parchment, 161 
 Parmelia, 153 
 
 Borreri, 156 
 
 conspersa, 154 
 
 caperata, 155 
 
 latissima, 157 
 
 multisporum, 154 
 
 olivacea, 155 
 
 perforata, 157 
 
 perlata, 157 
 
 physodes, 155 
 
 paxatilis, 156 
 
 taeniata, 155 
 Parmeliaceas, 144 
 Parry, 101 
 Paste-board, 24 
 Patella, 29 
 Peltigera, 193 
 
 aphthosa, 50, 193 
 
 canina, 23, 194 
 
 polydactyla, 191 
 Perfumes, 24, 101 
 Pertnsaria, 174 
 
 communis, 176 
 
 globnlaris, 175 
 
 gloiiierulata, 176 
 
 leioploca, 175 
 
 iiuiltipuncta, 175 
 
 pustulata, 175 
 
 Pertusaria, 
 
 velata, 176 
 Phylogenesis. 32 
 Phylogeny, 36 
 Physcia, 138 
 
 adglutinata, 139 
 
 aquila, 140 
 
 caesia, 139 
 
 ciliaris, 141 
 
 comosa, 141 
 
 hispida, 141 
 
 hypoleuca, 140 
 
 obscura, 139 
 
 parietina, 23 
 
 pulverulenta, 140 
 
 setosa, 139 
 
 speciosa, 141 
 
 stellaris, 140 
 
 tribacea, 140 
 Physciacese, 132 
 Physiology, 39 
 Pilophoron, 89 
 
 cereolus, 89 
 Placodium, 135 
 
 aurautiacum, 136 
 
 cerinum, 136 
 
 cinnabarinum, 136 
 
 citrinum, 136 
 
 elegans, 137 
 
 ferrugineum, 136 
 
 murorura, 136 
 Pleurococcus vulgaris, 35 
 Plinius, 3, 21 
 Pockets, 68 
 Podetium, 46, 92 
 Poisoning, 22 
 Poly-ancestry, 32 
 Polycoccus punctiformis, 35 
 Polyps, 6 
 Polychidium, 189 
 
 muscicohim, 100 
 Porcher, 121 
 Potatoes, 20 
 Powders, liair, 101 
 Preservation of lichens, 65 
 
232 
 
 GENERAL INDEX. 
 
 Priestley, green substance of, 
 Primal substance, 8 
 Propagation, vegetative, 9 
 Propagative organs, 49 
 Protococcus vulgaris, 8 
 Prototype, 32 
 Pseudo-lichens, 200 
 Psora, 118 
 
 atro-rufa, 119 
 
 decipieus, 119 
 
 icteria, 118 
 
 rufonigra, 119 
 
 Rusellii, 11§ 
 Psoroma, 191 
 
 hypnorum, 191 
 
 stellata, 191 
 Puff-balls, 26 
 Pulveraria, 200 
 Pustules, 178 
 Pycnidla, 51 
 Pyrenoid bodies, 35 
 Pyrenotliea, 200 
 Pyrenula, 170 
 
 aepistea, 171 
 
 nitida, 171 
 Pyxine, 137 
 
 cocoes, 138 
 
 picta, 138 
 
 sorediata, 138 
 
 Quinine, substitute for, 23 
 
 Rabies, 23 
 Ramalina, 160 
 
 calicarlB, 160 
 
 ceruchis, 161 
 
 homalea, 161 
 
 miuuscula, 160 
 
 polymorpha, 161 
 
 reticulata, 162 
 
 rigida, 162 
 Range, continental, 60, 
 Red cup moss, 97 
 Red pepper, 23 
 Reicheubach, 7 
 
 Reindeer moss, 20, 101 
 Reiuke, 2, 12, 13 ' 
 Rejuvenescence, 49 
 Rhizoids, 44 
 
 aerial, 44 
 Rinodina, 133 
 
 Bishoffii, 134 
 
 chrysomelsena, 135 
 
 constans, 134 
 
 oreina, 134 
 
 sophodes, 134 
 
 turfacea, 135 
 Rivularia nitida, 35 
 Rocella, 3, 21, 162 
 
 leucophfea, 163 
 
 tinctoria, 163 
 Rock, disintegration of, 17 
 Rock-hair, 166 
 Rock -moss, 122 
 Rock -tripe, 20 
 Roman empire, 21 
 Roots, 44 
 Rucellai, 21 
 Rucellarii, 21 
 Ruellius, 3 
 Rust, 26 
 
 Sac-fungi, 28 
 Sanders, 24 
 Saprophytes, 28, 29 
 Saussure, 149 
 Schweudener, 2, 11 
 Scrap-book, 68 
 Scrofula, 168 
 Scurvy, 20 
 Scytonema, 190 
 Shakespeare, 168 
 Sirosiphon,35, 186 
 Snails, 43 
 Solomon, 3 
 Solorina, 194 
 
 crocea, 195 
 
 saccata, 195 
 Soralia, 14, 107 
 Soralium, 49 
 
GKNERAL INDEX. 
 
 233 
 
 Soredia, 6, 37, 48 
 Soredium, 49 
 Speerschneidera, 153 
 
 euploca, 153 
 SpermagODia, 6, 11, 50, loc. 
 Spermatia, 10, 51 
 Spermatozoa, 11 
 Sphaerophorus, 86 
 fragilis, 86 
 globiferus, 86 
 Spilonema, 200 
 Spore-characters, 10 
 Spore-sac. 28, 47 
 Spores, 28 
 Sprengel, 7 
 Stahl, 12 
 Stane-raw, 156 
 Staney-rag, 156 
 Starch, 19 
 Sten-laf , 156 
 Stereocaulou, 90 
 condensatum, 90 
 coralloides, 91 
 denudatum, 91 
 paschale, 91 
 ramulosum, 91 
 Sterigmata, 51 
 Sticta, 49, 197 
 
 ampllssima, 198 
 Oregana, 50 
 pulmonaria, 198 
 Stictina, 49, 196 
 quercizaus, 197 
 tomentosa, 197 
 Stitzeuberger, 10 
 Stone-crottles, 155 
 Study of lichens, 63 
 Sturgis, 12 
 Substance, primal, 8 
 Substrata, 53 
 Sweden, 20 
 Switzerland, 10 
 Symbionts, 31 
 Symbiosis, 12 
 
 antagonistic, 31 
 
 Symbiosis. 
 
 mutualistic, 31 
 Systems, 73 
 
 artificial, 73 
 
 natural, 73 
 
 Tanning, 24, 27 
 Tartars, 19 
 Tartary, 19 
 Thalline type, 47 
 Thallophytes, 39 
 Thallus, 39 
 crustose, 40 
 foliose, 40 
 fruticose, 40 
 secondary, 92 
 vertical, 92 
 Thamnolia, lu2 
 
 vermicularis, 102 
 Thecae, 47 
 Thecium, 47 
 Thekes, 47 
 Theloschistes, 142 
 
 chrysophthalmus, 143 
 concolor, 142 
 flavicans, 143 
 leucomela, 144 
 lychneus, 142 
 parietiuus, 143 
 polycarpus, 142 
 Thelotrema, 172 
 
 lepadinum, 172 
 Theophrastus, 1, 3, 4, 21 
 Toad-stools, 26, 88 
 Tournefort, 1 
 Tree-hair, 166 
 Tree-moss, 168 
 Tripe de roche, 121 
 Trypethelium, 170 
 
 vireus, 170 
 Tiickerman, 12 
 Tulasne, 11 
 Type, crustose, 47 
 foliose, 52 
 fruticose, 44 
 
234 
 
 GENERAL INDEX. 
 
 Type. 
 
 fungal, 46 
 thalline, 47 
 
 Ulf-mossa, 22, 164 
 
 Umbilicaria, 20, 123 
 papulosa, 123 
 Pennsylvanica, 124 
 pustulata, 124 
 
 "Umbilicus, 44 
 
 Units, morphological, 6 
 
 Urceolaria, 145 
 
 actinostoma, 146 
 scruposa, 146 
 
 Usnea, 3, 167 
 
 barbata, 23, 168 
 linearis, 167 
 longissima, 168 
 
 Variolaria, 200 
 
 Vasculum, 58 
 
 Velvet-moss, 122 
 
 Verrucaria, 173 
 fuscella, 174 
 margacea, 174 
 
 Verrucaria. 
 muralis, 174 
 nigrescens, 174 
 pyrenophora, 174 
 rupestris, 174 
 
 Verrucariacefe, 169 
 
 Vesuvius, 92 
 
 Virey,22 
 
 Voigt, 7 
 
 Wallroth, 2, 8 
 Weather-side, 60 
 Weber, 1 
 
 Whooping-cougb, 23, 168 
 Willey, 
 
 Wolf's-moss, 22, 164 
 Woroniu, 13 
 
 Xylographa, 128 
 
 opegraphilla, 128 
 parallel! a, 128 
 
 York, duke of, 23 
 
 Zambia, 111 
 
PLATES AND DESCRIPTIONS 
 
PLATE I. 
 
 Algal Types. 
 
 1. Ci/stococciis (Protococcus). The individual cells are sur- 
 
 rounded by terminal branches of hyphae known as 
 haustorio. 
 
 2. Chroolepus. The branching chain of cells is enclosed by 
 
 haustorial hyphse. 
 
 3. Nostoc. The chains are intermingled with hyphas, which 
 
 form no haustoria. The larger cells in the chains are 
 known as heteroci/sts. 
 
 4. Gloeocapsa. The cells are small, enclosed by a thick strati- 
 
 fied gelatinous covering which is penetrated by the 
 haustorial branches. 
 6. Rivularia. Algae and hyphae. In Nostoc as well as in Rivu- 
 laria the individual chains are enclosed by a gelatinous 
 substance. 
 
 6. PobjcoccHS. Cells form colonies which are enclosed by 
 
 haustorial hyphae. 
 
 7. Dactijlococcus. The cells are elliptical. 
 
 8. Pleurococcus. The cells are irregular in outline and en- 
 
 closed by a dense hyphal structure. 
 
 9. Sirosiphon. This is a branching many-celled alga. The 
 
 figure represents a terminal branch. Hyphae are not 
 shown. 
 
GUIDE TO LICHENS Schneider, 
 
 plate I 
 
 ALGAL TYPES. 
 
PLATE II. 
 Lichen-types. 
 
 Crustose forms : 
 
 1. Calicium hypereUum. 
 
 2. Graphis scripta. 
 
 3. Rhwdina oreina. 
 
 Foliose forms : 
 
 4. Endocarpon miniattim. 
 
 5. Collema nigrescens. 
 
 6. Sticta puhnonarla. 
 
 Fruticose forms. 
 
 7. Cetraria Islandica. 
 
 8. Rocella tinctoria. 
 
 9. Usnea harhata. 
 
 1, 2 and 3 are about natural size. 4 to 9 inclusive are some 
 what reduced. 6, 7 and 9 represent only portions of 
 plants. 
 
GUIDE TO LICHENS Schneider. 
 
 Plate II. 
 
 LICHEX-TVPES. 
 
PLATE III. 
 
 Histology of a Foliose Lichen. 
 
 {Sticta amplissinia.) 
 
 \. Vertical section through apothecium : 
 
 a, b, thecium, consisting of the spore-sacs and para- 
 physes ; o, colored ends of paraphyses ; c, d, hypothe- 
 cium ; c, upper hyphal layer; d, lower cortical layer; e, 
 upper algal layer; /j medullary layer; g, lower algal 
 layer; h, cortical layer; /, rhizoids (aerial). 
 
 2. Vertical section through thallus: 
 
 a, epidermal layer ; b, upper cortical layer ; r, algal layer; 
 d, medullary layer ; e, lower cortical layer; /, rhizoids. 
 
 3. Paraphyses and spore-sac more highly magnified. 
 
 4. Spores highly magnified. 
 
 5. Algae {Protococcus} and haustoria. 
 
 1 and 2 magnified about 300 diameters ; 3, 4 and 5 more highly 
 magnified. 
 
GUIDE TO LICHENS Schneider 
 
 Plate III 
 
 HISTOLOGY OF A FOLIOS E L/CHEiV. 
 {Sticta amflissima.) 
 
PLATE lY. 
 Apothecial axd Thalline Types. 
 
 Apothecial types : 
 
 1. Fungal type of apothecium as it occurs in the (^ali- 
 
 ciaeese.. 
 
 2. Fungal type of apotheciuni as it occurs in tlie Cla- 
 
 doniaceae and some Lecideaceae. 
 8. Fungal type of apotheciuni as it occurs in the major- 
 ity of Lecideaceae. 
 
 4. Thalline type of apotheciuni as it occurs in the Phys- 
 
 ciaceae and Parmeliacea?. 
 
 5. Immersed type of apotheciura as it occurs in Endo- 
 
 carpoti and other genera. 
 Thalline types : 
 
 6. Crustose thallus. 
 
 7. Crustose thallus with upper cortical layer. 
 
 8. Foliose thallus without upper cortical la^'^er. 
 i>. Foliose thallus with both cortical layers. 
 
 10. Fruticose thallus as in Stereocauhn. 
 
 11. Fruticose thallus as in Cladonia. 
 
 12. Fruticose thallus as in Usnea. 
 
 All the figures are diagramatic ; 1 to 9 inclusive represent ver- 
 tical sections; 10, 11 and 12, longitudinal sections. 
 
GUIDE TO LICHENS. Schneider. 
 
 Plat* IV. 
 
 AFOTHECIAL AXD JHALLLVE TYPES. 
 
PLATE Y. 
 Generic Spore-tyfks. 
 
 1. Acarospora. 
 
 2. Acolium. 
 8. Alectoria. 
 
 4. Arthonia. 
 
 5. Arthothelium. 
 
 6. Bacidia. 
 
 7. Baeomyces. 
 
 8. Biatora. 
 
 9. Biatorella. 
 
 10. Biatorina. 
 
 11. Bilimbia. 
 
 12. Bryopogon. 
 
GUIDE TO LICHENS. Schneider. 
 
 Plate. V. 
 
 0)05 
 
 y 
 
 ^ 
 
 
 
 o 
 o o 
 
 OrP© 
 
 ^0 
 ^0 
 
 /JJ 
 
 SPORES. 
 
PLATE VI. 
 
 Generic Spore-types (con.). 
 
 13. Buellia. 
 
 14. Buelliopsis. 
 
 15. Caliciura. 
 
 16. Catillaria. 
 
 17. Celidiopsis. 
 
 18. Cetraria. 
 
 19. Cladonia. 
 
 20. Collema 
 
 21. Coniocybe. 
 
 22. Conotrema. 
 28. Cyphelium. 
 
 24. Dermatocarpon. 
 
GUIDE TO LICHEWS Sfht»«fdfr 
 
 Plate \'\. 
 
 
 Jl 
 
 ^1 
 
 Jl 
 
 6> 
 
 
 % 
 
 JS 
 
 
 ^ 
 
 
 a 
 
 o 
 
 O 
 
 ^^K^ 
 
 ^^. 
 
 \ 
 
 ^ 
 
 zc 
 
 O o 
 
 Vf 
 
 STORES, 
 
PLATE VII. 
 Generic Spore-types (con.)- 
 
 25. Endocarpon. 
 
 26. Ephebe. 
 
 27. Evernia. 
 
 28. Graphis. 
 
 29. Gyalecta. 
 
 30. Gyrophora. 
 
 31. Gyrostomum. 
 
 32. Haematomma. 
 
 33. Hazslinskya. 
 
 34. Heppia. 
 
 35. Hydrothyria. 
 
 36. Lecanora. 
 
GUIDE TO LICHENS. Schneider. 
 
 Plale VII. 
 
 iP 
 
 Z5 
 
 
 
 ^ 
 
 Z6 
 
 
 ^ <^ 
 
 27 
 
 ZS 
 
 ^ 
 
 M 
 
 % # 
 
 i2 
 
 JJ 
 
 O 
 
 55 
 
 Jo 
 
 SPORES. 
 
PLATE VIII. 
 
 Generic Spore-types (con.). 
 
 37. Lecidea. 
 
 38. Lecothecium. 
 
 39. Leptogium. 
 
 40. Lichina. 
 
 41. Lopadium. 
 
 42. Mallotiuin. 
 
 43. Megalospora. 
 
 44. Mycoporum. 
 
 45. Nephromium. 
 
 46. Omphalaria. 
 
 47. Opegrapha. 
 
 48. Pannaria. 
 
GUIDE TO LfrHENS. Schneider.. 
 
 Flatc Vin 
 
 S FOXES. 
 
PLATE IX. 
 
 Generic Spore-types (con.)= 
 
 49. Parmelia. 
 
 50. Peltigera. 
 
 51. Pertusaria. 
 62. Physcia. 
 5.3. Pilophoron. 
 
 54. Placodium. 
 
 55. Polychidiuni. 
 
 56. Psora. 
 57! Psoroma. 
 
 58. Pyrenula. 
 
 59. Pyxine. 
 
 60. Ramalina. 
 
GUIDE TO LICHENS Schneider. 
 
 Plate rX 
 
 SPOKES. 
 
PLATE X. 
 
 Generic Spore-types (con.). 
 
 61. Rinodina. 
 
 62. Rocella. 
 
 63. Solorina. 
 
 64. Speerschneidera. 
 66. Sphaerophorus. 
 
 66. Stereocaulon. 
 
 67. Sticta. 
 
 68. Stictina. 
 
 69. Theloschistes. 
 
 70. Thelotrema. 
 
 71. Trypethelium. 
 
 72. Umbilicaria. 
 
GUIDE TO LICHENS Sahn^ider 
 
 PJatt X. 
 
 SPORES. 
 
PLATE XI. 
 Generic Spore-types (con.). 
 
 73. Urceolaria. 
 
 74. Usnea. 
 
 75. Verrucaria. 
 
 76. Xylographa. 
 
GUIDE TO LICHENS. Schneider 
 
 PUte XI. 
 
 73 
 
 ^0 
 
 ^ 
 
 
 
 
 JM. 
 
 
 SPORES.