B-II47 l '“R,L\f~", September I974 APR Z b i975 phology and Anatomy Texas Persimmon as Agricultural Experiment Station Ier, Director, College Station, Texas i. . . 1i Cover Photographs Top, a typical infestation of multi-stemmed Texas persimmon plants on the D. B. Wood Ranch near Georgetown, Texas. Bottom, Sam Barkley, owner, with the largest recorded Texas persimmon plant in Texas near Uvalde. - CONTENTS SUMMARY .............................................................................................. .. 4 INTRODUCTION ................................................................................ .. 5 EXTENT OF INFESTATION ............................................................ -- 5 GENERAL MATERIALS AND METHODS .................................... .. 5 Sites .................................................................................................... .- 5 Field Plant Collection ............................................................... 6 Morphological and Anatomical Methods .................................... .. 6 Animal Feeding ................................................................................ .- 6 Growth Chamber and Greenhouse Plant Propagation .............. .. 6 Herbicide Spraying and Evaluation .............................................. -- 7 FLOWER, FRUIT ANDSEEDLING ................................................ .. 7 Flower, Fruit and Seed Morphology and Anatomy .................... .. 7 Flower .......................................................................... Q. ............ .. 7 Fruit .......................................................................................... .. 7 Seed ............................................................................................ .. 8 Seed Germination ............................................................................ -- 8 Physical and Chemical Treatments ...................................... -- 8 Fruit Pulp Inhibitor Study .................................................... .. 9 Seed Passage Through Animals .................................................. .. l0 Cattle .......................................................................................... .- l0 Spanish Goat ............................................................................ .. l1 Rambouillet Sheep .................................................................. .- ll Whitetail Deer .......................................................................... -. ll Raccoon .................................................................................... .- ll Summary of the Feeding Experiments .............................. _. ll Seedling Morphology ...................................................................... -. ll Seedling Growth Rate ............................................................ -. l1 Temperature Effects on Growth Rate .................................. .. l2 Seedling Surface ........................................................................ .. l2 Seedling Anatomy ............................................................................ -. 12 MORPHOLOGY OF THE STEM ...................................................... .. 25 Types and Sizes of Plants ................................................................ .- 25 New Stem Development ............. .. 25 Older Stem Development ................................................................ -. 25 ANATOMY OF THE STEM ................................................................ -. 29 New Stem Transections ............. .; ................................................... .- 29 One-Year-Old Stem Transections .................................................. -. 30 Older Stem Transections ................................................................ .- 30 Tangential and Radial Stem Sections .......................................... ._ 31 BUDS ................................................................................................ .-; ..... .. 35 Stem Buds .......................................................................................... .. 35 Root Buds ........................................................................................ -_ 35 Sprouting Characteristics of Stems and Roots ............................ .- 36 LEAF MORPHOLOGY AND ANATOMY ....................................... .- 41 Location and Number of Production .......................................... ._ 41 Morphology ...................................................................................... .- 41 Anatomy ............................................................................................ .. 41 ROOT MORPHOLOGY AND ANATOMY .................................... -. 47 Morphology .................................... ................................................ -. 47 Anatomy ............................................................................................ .. 47 SEEDLING RESPONSE TO HERBICIDES ........................ .1 .......... -- 53 DISCUSSION ......................................................................... ............... .. 53 ACKNOWLEDGMENTS ...................................................................... .- 53 LITERATURE CITED .................................... -.; ................................. .. 54 GLOSSARY .............................................................................................. -- 54 PHOTOGRAPH SYMBOL IDENTIFICATION LIST .................. .. 55 SUMMARY Texas persimmon (Diospyros texana Scheele) is an important, largely undesirable woody species which has invaded about 6 million acres of Texas, mostly on the Edwards Plateau, Central Basin and South Texas Plains. It also occurs in nothern Mexico. Texas persimmon produces male and female flow- ers on separate plants (dioecious). Most flowers ap- pear from March to May. The fruit, a black, de- pressed globose berry, ripens in August through Octo- ber. The seed are dark red and glossy; they contain an embryo and food reserves stored as a hard, lustrous endosperm. Seed germinate much more readily when washed free from the fruit pulp than when left in the fruit. Seedlings grow most rapidly at 80° F, but al- most no growth occurs at 65° F. Seed were fed to a Jersey steer (Bos taurus L.), a Spanish goat (Capra hircus L.) a Rambouillet sheep (Ovis aries L.) and a whitetail deer [Odocoileus vir- ginianus (Boddaert)]. Also, seed were collected in the field after they had passed through the digestive tracts of cattle and raccoons (Procyon lotor L.). Of 600 seed fed to the steer, only 289 were recovered, and only about 1 percent of these subsequently germinated. Of seed collected from cattle feces in the field,=22 percent germinated compared to 64 percent of the un- fed seed. Twelve percent of the seed washed from raccoon droppings germinated. The Spanish goat, Rambouillet sheep and whitetail deer masticated and digested essentially all the seed fed. Texas persimmon occurs both as individual plants and as mottes. Most are multistemmed plants 8 to 12 feet tall. However, the largest tree recorded in Texas is 26 feet tall with a crown diameter of 31 feet. Texas persimmon is seldom the height-dominant species, ex- cept where other woody plants have been removed. In Central Texas, new stems begin growth from apical buds in March and April, and complete elon- gation of about 5 centimeters [by the end of May. Flowers are located at the base of the new stem and at buds, primarily on the 1- and 2-year-old stems. Many stems produce short lateral shoots. At first the stem is green, but in May or June a simple periderm forms, turning the stem gray and slightly furrowed. Stems 1 to 2 centimeters in diameter are relatively smooth, as the surface periderm and outer phloem strip off annually in late summer. The apical stem meristem elongates, producing an axillary bud and a leaf at each node. Some axillary buds produce a shortlateral shoot the first year, and some produce stems, leaves and flowers the second year. However, most remain dormant until released 4 stem, except that it produces no axillary A ~thiuron [l-(S-tert-butyl-l,3,4-thiadiazol-2-yl)-l from apical dominance. When the stem is se, the top of the plant, usually about four new i] produced; when the entire top is removed, as j 20 vigorous stems are produced on the base stem and on the root. A Texas persimmon generally produces adv_ buds on the root either along cut edges o" branch roots join the main root. These bu ently arise on potentially meristematic tissu phellogen, phloem or cambium. When the cut off at the root, sprouts arise near the en tical roots but may occur all along the y roots. Plants can be propagated in the gree i, holding 3- to 4-inch-long stem or root segmen :_ 0.5-inch in diameter in soil for 2 to 6 mont ever, greenhouse plants l year old sprouted i‘ stem, but not from the root, when the plant ped at the soil level. a One leaf is produced at each node on n, The leaves expand to full size within 3 " emergence. At first they are light green; turn dark green. The largest leaves occur in section of the stem; younger and older l smaller. Most other leaves are produced on ' two older stem increments. These leaves are but appear almost whorled on foreshorten usually three to five leaves are produced on A shoots. The leaf blade arises on a 2-millimeter-li iole. The leaf blade is simple and obovate,j entire margin, acute base and an acute, emarginate apex. The upper blade surface i‘ glabrous, but the lower surface varies from i‘ to highly pubescent. Leaves vary from l t0 meters long, but most are 2 to 3 centime i They are slightly more than twice as long V The lower surface of the blade has 219 to 32 per square millimeter. i Seedling plants produce a prominent‘ Plants in the field also generally produce at However, plants growing in areas with sh" over rock generally have spreading, shallow tems until the roots can penetrate deeper int The structure of the root body is similar to ,1 contains no pith. a Of the herbicides tested on seedling pl i ylurea] and the potassium salt of picloram i 3,5,6-trichloropicolinic acid) were the most for controlling Texas persimmon. A as persimmon (Diospyros texana Scheele) is an 'ngly important woody plant which infests _ eas of Texas. It is also known as Mexican per- i , chapote and chapote prieto (15). It is bene- producing fruit that is readily eaten by many d mammals. Generally, however, Texas per- a is considered undesirable because it readily A: grassland, is difficult to control and is toxic i the fruit causes scours in cattle. Texas per- g commonly persists where chemical or me- f“ measures have been employed to control p‘ It readily resprouts from roots. Consequently, sure that fails to kill the roots allows it to be- stablished, frequently with significantly less ftion from other woody plants than before. aim of this study was to describe the plant e, seasonal growth patterns and seedling re- * to herbicides to provide a basis for developing methods of control. This study supplements information on woody species presented by 3 and Chalk (7) and Panshin and de gZeeuw he objectives were (a) to determine the mor- i'cal and anatomical structure of the fruit, seed- d mature plant; (b) to determine the seasonal g pattern and factors affecting growth; and (c) ‘ mine the response of greenhouse seedlings to ‘des. The response of Texas persimmon to her- in the field has been studied by others (5, 10, is study was undertaken in the field at George- , ano, Marble Falls, Sonora and Uvalde, Texas, , the greenhouses at College Station, Texas. hysiologist, Agricultural Research Service, U.S. Depart- ‘of Agriculture, The Texas Agricultural Experiment (Department of Range Science). ention of a trademark name or a proprietary product tot constitute a guarantee or warranty of the product U.S. Department of Agriculture or The Texas Agri- l Experiment Station and does not imply its ap- a to the exclusion of other products that also may be ~ lc. Morphology and Anatomy of Texas Persimmon (Diospyros texcma Scheele) e R. E. Meyer* EXTENT OF INFESTATION Texas persimmon grows in central, southern and southwestern Texas and in northern Mexico (16). Hoffmanl estimates that about 6 million acres of Tex- as rangeland are infested with Texas persimmon in the counties shown in Figure l. Wilson (l6) described Texas persimmon as a problem on the eastern edge of the Edwards Plateau and the Central Basin, including the following counties: Bandera, Blanco, Burnet, Comal, Gillespie, Hays, Kendall, Kerr, Kimble, Llano, Mason, McCulloch and San Saba. Scattered plants grow north of the Rio Grande River from Hidalgo County on the southeast to Terrell County on the west. Plants occur as far east as Dewitt, Goliad and Gonzales counties. Plants also have been observed in Brewster, Coleman, Concho, Tom Green and Travis counties. In a recent survey by Scifres and Hoffman? range workers in Texas felt that density increases of Texas persimmon can be attributed primarily to over- grazing and the use of mechanical brush control meth- ods that‘ fail to kill the plant. Texas persimmon occurs in the states of Nuevo Leon, Coahuila and Tamaulipas in northern Mexico (l5), but no infor- mation was found on its distribution in those States. GENERAL MATERIALS AND METHODS Sites The research was conducted in the greenhouse facilities at College Station and at field sites in Georgetown, Llano, Marble Falls, Sonora and Uvalde, Texas. Most plant samples were collected at the D. B. 1Hoffman, G. O. 1974. Private communication; Texas Agricul- tural Extension Service, Texas A8¢M University, College Station, Texas 77843. "Scifres, C. J. and G. O. Hoffman. 1974. Distribution of Texas Persimmon (Unpublished Survey), The Texas Agricultural Ex- periment Station (Department of Range Science), Texas A8¢M University, College Station, Texas 77843. 5 Texas Persimmon Distribution Acreage Infested (°/<>) 70-95 I 50-69 E 25-49 5-24 B 1-4 Figure 1. Infestation of Texas persimmon (Diospyros texana Scheele) in Texas, 1974. (Courtesy of C. J. Scifres and G. O. Hoffman). “food Ranch ilear Georgetown, on the eastern edge of the Edwards Plateau. On this ranch, Texas per- simmon was a scattered infestation of about 2O plants per acre. The plants were 6 to 12 feet tall and grew on rocky loam soil. Other woody species on the area included live oak (Quercus virginiana Mill.) with scattered cedar elm (Ulmus crassifolia Nutt.) and pricklypear (Opunlia sp.). The remaining plant sam- ples were collected in the Central Basin on the Ann Etta Hall Ranch near Llano and the Fred Horlen Ranch near Marble Falls. Other woody species in these areas were largely honey mesquite [Prosopis juliflora (Swartz) DC. var. glandulosa (Torr.) Cockerell], white- brush (Aloysia lycioides Cham.) and tasajillo (Opun- tia lcploczitllis DC.). Field Plant Collection Immature and ripe fruit were collected from plants near Georgetown, Llano, Marble Falls or So- nora from 1967 through 1973. Stem and root samples were collected at the D. B. “food Ranch near George- town l4 times in 1969 and 13 times in 1970. Twigs, stems l, 2, 4 and 8 centimeters in diameter, and roots of various sizes were collected at each date. The twigs included tip growth from the previous year and new shoots when they occurred. The twig samples con- tained leaves and buds; flowers were collected when present. Segments about 1 centimeter long were cut from stems l and 2 centimeters in diameter. On 4- and S-centimeter-diameter stems, sections were re- moved by sawing transectional cuts with a hand saw and chipping out the tissue with a hammer and chisel. Root samples were often difficult to secure because of the rocky soil. However, root samples 0.5, 1 and more than 2 centimeters in diameter were collected on each date. Samples were taken from two or three 6 trees on each date. Miscellaneous other stem samples were collected at Georgetown and Lla b early in 1973. The tissue was placed in a Cra solution (13) immediately after cutting. A Morphological and Anatomical Metho All photographs were made with 4- by 5-in eras. Overall photographs fwere made with; Plus-X Pan Professional film? Enlarged plant . and histological sections were photograph either Kodak Panatomic-X or Ektapan Pro‘. film, which was developed either in Kodak or DK-GOA for adequate contrast in detail. , Anatomical sections were prepared by fi tissue in a Craf solution (13) comprised of 30 ' of a l-percent aqueous chromium trioxide sol i, percent concentrated acetic acid, l0 percent w, percent formalin solution and 57 percent A volume. The tissues were dehydrated in etha tertiary butyl alcohol and embedded in (m.p. 101° to 104° F). The embedded samp microtomed 8 to 20 microns thick. The tiss y stained with safranin (30 minutes) and fast 31 to 5 minutes) (13). a Stomatal counts were made on three fiel an ocular-mounted rectangular reticle on eaci leaves. Stem and root tissue dimensions w sured either on transections of stored tissu had been fixed in the Craf solution and par , hydrated to 70 percent ethanol in water, or i tissue held in water. The blocks of stem or r y mounted directly into a rotary microtome, g tions 2O microns thick were prepared. The . either were left unstained or were stained i. ranin and mounted in a glycerol:water (1:1) Dimensions were measured on three radii stem or root in each size group at every date; Animal Feeding z Texas persimmon fruit and/or washed seed: to a 400-pound jersey steer (Bos taurus L.), a- goat (Capra hircus L.), a Rambouillet she arias L.) and a whitetail deer [Odocoiletts vir (Boddaert)]. The numbers of fruit and see included with the results. All animals were: pens with concrete floors. The fruit for all whitetail deer was force-fed, and washed i mixed with feed grain. The deer readily ate , Feces were collected daily for 5 or 6 days after‘ All experiments were repeated. The seed recovered daily from each animf were counted, washed and germinated in t_i house. No more than 25 seed were planted Also, 100 or 200 washed, unfed seed were p) a control with each experiment. The pots we , in a warm greenhouse and kept watered for, 3 months. Growth Chamber and Greenhouse Plant Propagation 7 Plants were propagated from seed that washed free from the fruit pulp and stored r y 10 seed were placed on the surface of a soil ii comprised of Houston clay loam soil, washed peatmoss and Perlite at a 10:6:3:3 volume to e (v/v) ratio in a plastic pot 5 inches in di- i. The seed were covered with 1 inch of sand. soil mixture and sand potting procedure was ? roughout the study. The pots were kept in the ouse. The seedlings were subsequently thinned -" to five per pot. ree growth chambers were used for temperature iuit inhibitor experiments and for precondition- ants before spraying with herbicides. The plants vept on a 12-hour light (1,000 foot candles) and ycle at 80° F. A mixture of fluorescent and in- . ent illumination was used. Herbicide Spraying and Evaluation nts were propagated from seed in the green- . Because of their slow growth rate, they were ditioned in growth chambers for 2 months un- . to 18 inches tall. Eight pots of plants (replica- 'were sprayed with a laboratory sprayer (1) for Qtreatment. All herbicides were applied at 1 _ per acre in water at a spray volume of 20 gal- 'r acre. The plants were subsequently kept in eenhouse for 3 months. They were then eval-- i for percentage defoliation and percentage dead y. The experiment was repeated. e herbicides used included amitrole (3-amino-s- e); atrazine [2-chloro-4-(ethy1znnino)-6-(isopro- iino)-s-triazine]; bromacil (5-bromo-3-sec-butyl-6- luracil); cacodylic acid (hydroxydimethylarsine j dicainba (dimethylamine salt of 3,6-dichloro-0- i acid); 2,4-D [butoxy ethanol ester of (2,4-dich- '. enoxy)acetic acid]; dichlorprop [butoxy eth- Ster of 2-(2,4-dichlorophenoxy)propionic acid]; i [butoxy ethanol ester of 4-(2,4-dich1orophen- l tyric acid]; fenac [sodium salt of (2,3,6-trich- enyl)acetic acid]; karbutilate [tert-butylcarba- l id ester with 3-(m-hydroxyphenyl)-1,l-dimethy- .~; MCPA [dimethyl amine salt of [(4-chloro-0- xy]acetic acid]; mecoprop [butoxy ethanol ester 4-chloro-0-tolyl)oxy]propionic zicid];MCPB [bu- thanol ester of 4-[(4-chloro-0-tolyl)oxy]butyric i picloram (potassium salt of 4-amino-3,5,6-tri- picolinic acid); picloram + 2,4,5,-T [triethyla- lts of picloram + (2,4,5-trichlorophenoxy)acetic lfsilvex [butoxy ethanol ester of [2- (2,4,5-trichlo- yoxy)propionic acid]; tebuthiuron [l-(5-tert- ,3,4-thiadiazol-2-yl)-l,3-dimethylurea]; and 2,4,5- toxy ethanol ester of 2,4,5-T). FLOWER, FRUIT AND SEEDLING ' Flower, Fruit and Seed Morphology and Anatomy xas persimmon is dioecious, in that male and y flowers are produced on separate trees. At town, male and female trees were intermingled jere about equal in numbers. Most flowers ap- rom March to May; however, a few open later in the growing season after periods of abundant rain- fall. The flowers appear either solitary or in clusters of 2 or 3 on the distal end of branches that were pro- duced either the previous two seasons or early in the same season (Figure 2).“ According to Britton (2) The staminate flowers are on nodding hairy pedicels, iisii- ally in clusters of 2 or 3; the calyx is about 3 mm. long, deeply 5-lobed, and silky; the corolla is urn-shaped, twice the length of the calyx, white, scarcely 5-lobed; the l6 stamens are distinct, in two rows; the anthers are linear- lanceolate, and open at the apex; the pistillate flowers are usually solitary on shorter pedicels, their calyx silky, half the length of the hairy corolla, which is nearly 12 inm. across; ovary ovoid, 8~celled, with l ovule in each cavity. and 4-spreading, 2-lobed styles; there are no stamens nor staminodia. ' Floral structures are shown in Figure 3. Figure 3A shows an overall view of male flowers on April 15, 1971. Typical male flowers with part of the corolla and calyx removed are shown in Figure 3B. Large numbers of male flowers are frequently produced on one stem but fewer female flowers are produced (Figure 2). Mature, intact female flowers are shown in Figure 3C and with part of the corolla and calyx removed in Figure 3D. Fifteen male stems with four elongation-growth increments each were collected from plants at George- town on April 1, 1971. Branch increments, beginning at the youngest (the one produced in 1971), averaged 1.6, 5.4, 7.0 and 9.9 centimeters in length and had 4.0, 15.5, 6.5 and 0.4 flowers, respectively. The flowers on the youngest increment were at the base. Fifteen sim- ilar female stems had branch increments 1.5, 5.7, 6.8 and 8.4 centimeters long with 2.1, 3.3, 1.4 and 0.3 flowers, respectively. The flowers of Texas persimmon produce nectar, and when open, are visited by numerous insects. On April l and 5, 1974, insects were captured on flower- ing plants at Georgetown. The most numerous in- sects visiting the flowers were the honey bee and the two types of halictid bees (Table l). However, a num- ber of other insects were present which probably are important for pollination. Consequently, Texas per- simmon may be either partially or entirely insect pol- linated. Fruit The fruit ripens from August through October. “The fruit . . . is a depressed globose berry, 2 cm. in diameter, black and tipped by the style and sub- tended by the enlarged, reflexed calyx-lobes; the skin is thick, the pulp sweet, dark colored, and contains 3 to 8 triangular seeds” (2). Figure 4A shows the intact fruit in various stages of maturity. The immature fruit is green and pubescent. The fruit turns from entirely green to splotchy green and black before turning com- pletely black at maturity. The fruit is firm when green, and soft when black and mature. Figure 4B shows a transection of a fruit that pro- duced five seeds. The fleshy mesocarp turns darker “Fi tires are laced at the end of the res ective sections. Letter- g p . - I a p ing on photographs 1S identified on page 55. Table 1. Insects captured on Texas persimmon plants, April 1 and 5, 1974 during the flowering period at Georgetown, Texas Order Family Common name Scientific na Coleoptera Cantharidael Soldier beetle Chau/iognathus margina Chrysomelidae Leaf beetle Nodonata tristis (Oliv.l e- Cu rculionidae Weevil Anthonomus faber Dietz- Diptera Calliphoridae1 Blowfly ~ Chloropidael Frit fly Tachinidael Tachinid fly ,7 Hemiptera Coreidae Leaf footed plant bug Acanthocephala termin ~‘ Lygaeidae Lygaeid bug Nysius sp Miridae Plant bug Neuroco/pus sp Hymenoptera Apidael Honey bee Apis me/Iifera L. Halictidael Halictid bee Agaposteman sp Halictid bee Lasiog/ossum sp , Vespidael Vespid wasp Stenodynerus anormis Lepidoptera Danaidael Monarch butterfly Danaus plexippus (L) g Hesperiidae Skipper Ata/opedes campestris = 4/ Nymphalidael Painted beauty Vanessa virginiensis (Dr A Pieridae Alfalfa caterpiller C0/ias eurytheme Bolsd w Sulfur butterfly K ricogonia castalia Fab. _‘ Neuroptera Mantispidae Mantispid C/imaciel/a brunnea (S t Odonata Libellulidae Dragonfly 1 lFamily members listed probably involved with pollination. orange rapidly after being exposed to the air. Ap- parently colored oxidation products form rapidly in the mesocarp when it is exposed to oxygen upon cut- tmg. Figure 5 shows transections through a full-size but immature fruit collected at Georgetown April 21, 1969. The exocarp is a single layer of epidermal cells, with a cuticle and some trichomes. The mesocarp is comprised of a layer of about 40 parenchyma cells deep underneath the epidermis. They enlarge pro- gressively from the outside toward the center, and most of these parenchyma are more or less spherical. Sclereids occur singly or in small groups about 5 cells deep from the epidermis. Vascular bundles (Figure 5A) occur in the paren- chyma in an undulating line outside the seed cavities and in a ring at the center (Figure 5B). The endo- carp of the fruit consists of one layer of flat cells, with little or no cuticle to the inside of the mesocarp. Im- mature seed sections are shown in Figures 5B and 5C. Upon ripening of the fruit, the parenchyma become more irregularly shaped and more loosely packed than in the immature fruit. Seed , The seed are triangular, about 8 to l0 millimeters long and 1 to 2 millimeters thick. The thin edge is almost straight (Figure 6A). The seed are dark red and glossy. The food reserves are stored as hard, lustrous endosperm, and an embryo lies in a hollowed area at one end of the seed (Figure 6B). The seed is similar to that of common or eastern persimmon Diospyros virginiana L.) (6, l4). The outer covering of the seed (Figure 7A) is comprised of 1 or 2 layers of large cells which stain brown with safranin; they are covered with a cuticle. These cells are underlain by 1O to 15 smaller cells, 8 which are either cubical or elongated on the; tion. The endosperm is white, lustrous .{_ (Figures 7A and 7B) and forms a protective j as well as a food supply for the embryo (Fi The endosperm comprises the bulk of the and consists of a network of elongated cell stain green with fast green (Figure 7A). i The embryo occurs in a hollow of the e at one end of the seed (Figure 6B). The em, two cotyledons with net veination (Figure7 veins converge at the base of the cotyledons tering the primary root (Figure 7D). The I root narrows to a point near the edge of the i (Figure 7E). Frequently, the embryo will bei to the outside if the seed is killed and placed in water. f Figure 8 shows histological longitudinal - the embryo through the apical meristem at t I the cotyledons (Figure 8A), the primary i! section (Figure 8B) and the primary root ti {I 8C). Seed Germination , Seed in mature fruit did not germina / when planted in soil in the greenhouse; sub 1: germination of seed under different envir conditions was studied. a Physical and Chemical Treatments , Two experiments were conducted to eva mination of washed seed and seed in intact the first, 140 pots were filled with the soil; Ten washed seed were placed in each of half; Two fresh, chilled (4l° F) fruit, each contain five seed, were placed in each of the other pots. The seed were then covered with washed sand. The seed or fruit were pla placed in the greenhouse on September 7, l_ rcentage germination, root length and percentage Texas I seedlings with stems after several physical and chemical Root Seedlings Germination length with stems (%) (mm) (%) Plated October 4 and’ rated December 30, 1968 i ified control 92 2o 6 f . - tip 97 17 13 A ird of seed removed 97 6 4 ter, 10 min 93 21 9 f m, so min 94 17 3 Plated September 18 and rated t November 18, 1968 i’ ted 89 41 2o 'de control2 87 1 1 5 trated H2804, 2 min2 so 10 4 y trated H2804, 1o min2 s8 12 15 a trated H2804, 3o min2 32 3 4 trated H2804, so min2 42 2 o i, ure 720150 F. s applied as a fungicidal slurry. lings were washed from five of the pots from up weekly for 14 weeks. The seedlings were n a fixing solution for subsequent anatomical , At the end of l4 weeks, 88 percent of the A‘ seed and 13 percent of the seed in fresh, ifruit had germinated. ycond, similar experiment was conducted _ air-dried fruit were included, as well as y. " seed and fresh, chilled fruit. At the end of s, 43, 16 and 3 percent of the washed seed, I fresh, chilled fruit and seed in air-dried fruit, vely, had germinated. Thus, the fruit pulp dan inhibiting mechanism which prevented '- from germinating. . 'rd experiment was conducted to study the in- y of scarification and hot water treatments on tion and seedling growth. The treatments in- (an unscarified control, scarification of the seed i at the end of the embryonic root, removal of third of the seed at the end opposite the em- d immersion of the seed in hot (l36° F) water "ods of l0 and 60 minutes. Twenty washed t e placed on filter paper in each of five plastic shes, 9 centimeters in diameter, per treatment. i hes were placed on a naturally lighted labora- i4 ch at 72i5° F and were kept moist with dis- ater for 6 weeks. treatments gave 192 percent or more germina- g tlow production of stems (Table 2). No treat- as superior to the control. Root length was the same in most treatments, except that re- of the top third of the seed reduced the root Apparently, the reduction in food materials exposure to diseases resulted in less root . At the end of the experiment, 5 to 20 percent of the surfaces of all petri dishes were contaminated with a white fungus. A fourth experiment was conducted to investigate the possibilities of reducing fungus contamination and accelerating seed germination. The petri-dish technique was similar to that used in the scarifica- tion and hot water treatments. On September 18, 1968, five plastic petri dishes, each with 20 Texas persimmon seed, were prepared for each of six treat- ments at three temperatures. The seed treatments consisted of the following: an unscarified control, an unscarified control with a thiram [bis(dimethylthio- carbamoyl)disulfide] fungicide slurry treatment and immersion in concentrated sulfuric acid (H2504) for 2, 10, 30 and 60 minutes. The seed treated with acid were subsequently rinsed with tap water and treated with the fungicide slurry. One set each was placed in dark growth chambers at 60° and 86° F. A third set of dishes was placed on a naturally illuminated lab- oratory bench at 72° F. The results of holding the seedlings at 72° F are presented in Table 2. The concentrated H2504 treat- ments for 30 and 6O minutes reduced seed germina- tion and root length. Thiram did not affect germina- tion, but it did retard root growth compared to the untreated control. At 60° F, none of the seed germi- nated (data not shown). Apparently the temperature was too low for growth. Seedlings held at 86° F ger- minated about the same as those held at 72° F but failed to elongate as well, probably because of the inability to photosynthesize. Comparisons between the two highest temperature regimes are limited be- cause the seedlings were grown under different light conditions, which were undoubtedly important dur- ing a 2-month period. In summary, Texas persimmon seed germination is markedly inhibited by the fruit pulp. None of the scarification, hot water or acid treatments promoted earlier germination, longer root growth or earlier stern production. Microbial contamination was abun- dant in the petri dishes and was not satisfactorily con- trolled by a fungicide treatment. Fruit Pulp Inhibitor Study Further research was conducted on the inhibitor in the fruit pulp (8). Crude extracts were made by macerating the fruit pulp (without seed) in water with a blender. The macerated mixture formed a char- treuse foam above a dark yellow liquid. Ten milli- liter volumes of 5, l, 0.1 and 0.01 milligram per milli- liter concentrations of the extract were pipetted into plastic petri dishes with two pieces of filter paper. Distilled water was subsequently added to keep the seeds moist. In the first experiment, mechanically scarified honey mesquite, sorghum [Sorghum bicolor Moench.] and wheat (Triticum aestivum L.) seed were germinated in extracts of the fruit pulp. Twenty-five seed of each species were placed on filter paper in each of the four plastic petri dishes for each treat- 9 Table 3. Root length and percent germination of honey mesquite, sorghum and wheat seedlings germinated 4 to 6 days at 80° F1 Species Honey mesquite Sorghum Wheat Concentrationz Root length Germination Root length Germination Root length (mg/ml) (mm) (%) (mm) (%) lr_nm) o 18.6 a 99 a 14.1 a 69 a 29.0 a 0.1 14.3b 100a 12.9a 61 a 12.2b 1 3.7 c 94 a 6.6 b 28 b 11.0 b 5 0.9d 63b 1,2c 11c 0.1c 10 1.1d 70b 0.3d 8c O c lMeans within columns followed by the same letter are not significantly different at the 5% level, as determined by Duncan's T8811. 2Ten ml of the extract were added initially; subsequently, distilled water was added as required. ment, and the extract was added. Seed were germi- nated at 80° F. Root length and percent germination were recorded 4 to 6 days after exposure to the various fruit extracts. Germination and root elongation of all three species were strongly inhibited by the Texas persim- mon fruit extract (Table 3). As concentration of the extract was increased, growth inhibition of roots in- creased. Root-length measurements were more usable as a bioassay than was percentage germination, al- though germination was inhibited at the higher con- centrations of extract. Texas persimmon fruit were collected at various stages of development on May 20, June 6, July 7, August 26, September l0 and October 1, 1969, at Georgetown and stored at 41° F. Fruit were macerated as in the previous experiment. The entire fruit were macerated at the first two dates; the seed were re- moved at all other dates. Honey mesquite root length was used as the bioassay. Averaged over six dates, concentrations of 0.01, 0.1. 1 and l0 milligrams of fruit pulp per milliliter re- duced honey mesquite root length markedly to 68, 46, 23 and 12 percent of that of the control, respectively. The inhibitor was about equally effective at all stages of fruit development. In other experiments, extracting the fruit pulp with hexane or a 1:1 mixture of diethyl etherzhexane did not affect the recovery of the inhibitor compared to water. Filtering and freezing the extract for 5 hours likewise had no effect. However, the inhibitor was lost by boiling the extract to dryness and resus- pending in distilled water. Further research is needed to characterize this inhibitor fully. Seed Passage Through Animals Cattle A ‘100-pound Jersey steer was fed three lots of 200 washed Texas persimmon seed in 1972. The seed were mixed with small amounts of grain and fed on April 11, 19 and 25. The steer was kept in a pen with a concrete floor, and all feces were collected daily dur- l0 ing the 6-day period after each feeding. T’ are presented in Table 4. In the three runs, percent of the number of seed fed, were reco the 200 fed each time, the numbers recove i from 68 to 142. The largest number of w creted the second day after feeding. Howe L“ were recovered as long as 6 days after feedl gradual passage of seed is caused by the c_ mixing of the feed in the rumen. Since th‘. heavier than the other rumen contents, so seed probably were retained for varying 1 time. Remastication destroyed others. Thef system reduced the germination from 36 vif‘ unfed controls to less than 1 percent wh _ through the steer. On September l5, 1972, Texas persi were collected in cattle feces in the field town and Marble Falls. Some lots of feces» ' numbers of seed, indicating the animals? abundantly on the Texas persimmon fruit. 1 dred seed from feces, as well as 100 seed W fruit at each location, were planted, 25 per greenhouse at College Station. On Nov 1972, the seedling stems were about 4 centi Again, germination of seed from feces (2 was markedly less than that from fresh, w , (64 percent). There was no difference in \ tween the two sites. A Table 4. Texas persimmon seed recovered from a H steer in 1972, after feeding 200 seed at each of three ~ Date fedl Days after :~ feeding April 11 April 19 April 25 '1 (Number) (Number) (Number) f 1 0 2 3 2 21 92 27 3 26 24 14 4 13 22 15 5 18 2 7 '6 1 0 2 Total 79 142 63 lFewer than 1 percent of the seeds recovered had - , July 20, 1972, whereas 36 percent of the unf germinated. : gxas persimmon seedling length during a 14-week period i tion Seedling organ length Root Hypocotyl Stem (mm) (mm) (mm) 0 0 0 2 0 0 28 6 0 17 7 0 56 8 0 88 30 10 91 35 12 91 30 24 76 29 24 88 21 33 99 20 31 142 23 45 122 20 53 128 19 51 i, cattle appear to spread Texas persimmon ‘A They reduce germination markedly, but seeds remain viable to infest the area, partic- ihen large numbers of the fruit are eaten. ltly cattle like the fruit. Unfortunately, calves ‘scours after eating large numbers of fruit. jGoat ebruary 1969, one Spanish goat was fed 100 Seed in feed, and another was force-fed 1O in- ture fruit (about 5O seed). Feces were col- ‘ily for 5 days. The experiment was repeated. 2 were recovered from either source of seeds l. f run. Consequently, goats do not appear to grtant for spreading Texas persimmon. " illet Sheep ' ebruary 1969 and April 1972, a Rambouillet i“ fed 200 washed seed in a grain mixture. ere collected daily for 5 days. Each experiment ated each year. Only two seed were recovered year. These may have been dropped on the floor from the feed tray and mixed with the fithout actually being ingested. Therefore, '0 not seem to be an important source of ‘ng Texas persimmon, because first, they do the fruit freely when herbaceous vegetation Able, and second, they masticate and digest the y Deer ebruary 1969 and 1970, a whitetail deer was . washed seed in the feed, and another was fed ct, mature fruit (about 50 seed). The penned gerly ate the fruit fron1 hand feeding. The ere collected for 5 days. The experiments were f1 No intact seeds were recovered in either nly seed fragments ever were found. Conse- , , whitetail deer are not an important means of 'ng Texas persimmon, even though they eat the large numbers. a l September 15, 1972, raccoon feces contining numbers of Texas persimmon seed were col- lected at Marble Falls. The seed were washed from the feces; 25 were subsequently planted in each of four plastic pots containing the soil mixture. On November 29, 1972, 12 percent of the seed had germi- nated, in comparison to 64 percent of the seed washed from the fruit before planting. Consequently, rac- coons could be an important means of spreading Tex- as persimmon even though they reduce germination of the seeds markedly during digestion. Summary of the Feeding Experiments These experiments indicate that cattle readily pass about half the number of seed eaten, but markedly reduce the viability of most that do pass. However, because of passing large numbers of seed, they could readily spread Texas persimmon. Raccoons readily pass the seed, leaving about 12 percent viable for ger- mination. The Spanish goat, Rambouillet sheep and whitetail deer destroy all or almost all of the seeds consumed. Hamilton (4) reported that nine-banded armadillos (Dasypus novemcinetus var. texanus L.) readily ate Texas persimmon fruit near San Antonio, Texas, but he did not check the resulting seed for germination. Seedling Morphology Seedling Growth Rate An experiment was conducted in the greenhouse to determine the growth rate of Texas persimmon. Nylon screen packets containing 100 seed treated with thiram were buried in damp peatmoss in a refrigera- tor at 41° F. Initially and at weekly intervals, a packet of seed was removed. Twenty seed were then planted in each of five plastic pots filled with the soil mixture. The experiment was initiated October 2, 1968. Per- cent seedling emergence and average seedling height were recorded 14 weeks later. At 14 weeks, 88 percent of the seed had germinated (Table 5). The first seed germinated in about 2 weeks. The number generally increased progressively during the remainder of the 14-week period. Apparently these seed with endosperm require a longer period to germinate than seed of honey mesquite (9) and other species that have food reserves stored in their cotyle- dons. No reason was found for the characteristic var- iation in germination time for the Texas persimmon seed. Figure 9A shows a series of typical seedlings 2, 3, 4, 5, 6, 8, l0, 12 and 14 weeks old. Upon germination, a black taproot emerges and elongates continuously during the 14-week period. In fact, appreciable tap- root elongation occurs before the epicotyl begins elongation. Generally the taproot reaches the bottom of the pot before much lateral root growth occurs. Subsequently, in the pot, the major emphasis on root growth is on lateral root production. The hypocotyl emerges from the seed coat about the third week. The hypocotyl straightens out the fifth or sixth week, pulling the cotyledons covered with the empty seed coat from the soil. The hypo- cotyl ceases elongation at 19 to 35 millimeters. Most ll Table 6. Texas persimmon seedling growth at three temperatures over a 121-day periodl Date sampled in 1968 and 1969 Tempera- Measurement ture Dec 17 Jan 20 Mar 4 Apr 17 1° Fl Plant fresh weight (g) 95 0.83 a 1.42 b 1.58 b so 0.422 1.10 b 2.02 c 3.54 c 65 .84 a .73 a .76 a Stem length (cm) 95 6.6 b 9.8 b 13.5 b 8o 3.92 5.4 ab 12.4 c 15.4 t; 65 4.4 a 4.4 a 5.8 a Root length (cm) 95 36 a 37 a 38 a so 302 43 a 47 b 7o b 65 37 a 39 a 35 a lValues in the same column for each measurement followed by the same letter are not significantly different at the 5% level using Duncan's multiple range test. 2Plants sampled at the beginning of the experiment. cotyledons al)scise from the stem the fourth through the sixth week. The epicotyl was green and began elongating about the sixth week; it attained a mean length of 51 millimeters by the 14th week. The new stem produced 4, 5, 8 and 16 leaves at 8, 10, 12 and 14 weeks, respec- tively. The first four to seven leaves above the cotyle- dons became progressively larger. Subsequently leaves were the same size. Growth of Texas persimmon seedlings is erratic in the greenhouse. Stems continue to elongate, but at various rates. Most greenhouse plants 1 year old were 18 to 24 inches tall (Figure 9B). The stems are gray. Some plants become long and spindly, whereas others are shorter and branched. Older leaves abscise periodically, and new ones are subsequently produced. The new leaves are light green and gradually turn darker. Temperature Effects on Growth Rate An experiment was conducted using growth cham- bers to determine the influence of temperature on seedling growth. On December 17, 1968, 15 plastic pots filled with the soil mixture, each with five Texas persimmon seedlings with stems 2 to 8 inches tall, were placed in growth chambers set at 65°, 80° and 95° F, respectively, with 12-hour light and dark pe- riods. Five pots of plants were used initially, and five pots of plants were taken from each growth chamber on January 20, March 4 and April 17, 1969. The seed- lings were washed free from the soil, and the surface was allowed to air-dry. Stem and root lengths and seedling fresh weights were measured. Texas persimmon seedlings grew best at 80° F and poorest at 65° F (Table 6). Plant fresh weight increased from 0.42 grams on December 17 to 0.76, 3.54 and 1.58 grams at 65°, 80° and 95° F, respectively, on April 17. Thus, the plant weight at 80° F was 12 more than twice that of plants held at 95° F, a’ than four times greater than that of plants 65° F. Stem length was slightly longer for seedli t at 80° F than for those held at 95° F; this rep a an increase in stem elongation of about f0 a between December 17, 1968, and April 17, l days later. Stems of seedlin-gsiheld at 65° F el no more than about 2 centimeters in the same} Roots on seedlings held at 80° F were almost _ long as those held at the higher and lower t tures. Seedling Surface y Typical views of a IS-week-old seedling ar in Figure 10. Figure 10A shows the stem epidermis and numerous unicellular trichom stem has very slight vertical ridges. A leaf A to the right. Figure 10B shows the cotyledon area. The first true leaf is present. The co have since abscised, exposing one of the late , The leaves are arranged in an alternate patter stem. Figure 10C shows the root midsection I very slight vertical ridges. Figure 10D shows tip. i Seedling Anatomy Figure ll shows a series of transections f i week-old seedling with a hypocotyl and root? of 70 millimeters long. The hypocotyl (Fi contains many starch granules in the cortical ' parenchyma. The secondary phloem and most form a complete cylinder on either well-defined cambium. Figure 11B shows a r section 40 to 50 millimeters from the root tissues are similar, but less developed than the hypocotyl. In the transection taken 20 to _ meters from the root tip (Figure 11C), the forms a complete ring, and the xylem appear groups of three or more vessels. In the sectio millimeters from the root tip (Figure 11D), v secondary tissue occurs. A well-defined pith is Few, if any, starch granules occur in the par) of either the cortex or pith at this stage. l Figure 12 shows transections through a 13-‘ Texas persimmon seedling. Figure 12A sho x section through the third internode. A perid prised of the phellem and phellogen has form’; outer cortex. Bundles of lignified fibers lief side the phloem. The secondary xylem is Q veloped, being about 20 cells deep and lignif pith parenchyma have thick walls. The J structure (Figure 12B) is similar to that of internode, except that the periderm is more d The root section 10 to 20 millimeters r hypocotyl (Figure 12C) has well-defined i; phloem and xylem, but the outer tissues still; prised of an epidermis and cortical paren ' pith is present, and the parenchyma cells a) with starch granules. The section 30 to 40 mi, below the hypocotyl (Figure 12D) has an 3 about l0 xylem cells deep. The section 60 to limeters from the hypocotyl (Figure 12E) has a complete ring of secondary phloem and y A pith is still present, and the constituent All yma cells contain starch granules. Pith varies root; however, it usually disappears 150 to 200 eters below the hypocotyl. re 13 shows longitudinal radial views o-f a 13- ld seedling stem at or near the growing point. L 13A is the growing point showing the apical several leaf primordia and two lateral bud dia. Figures 13B and 13C show progressively developed lateral bud primordia and leaf peti- igure 13D is a radial section of the stem about imeters from the growing point. Three entire ions of trichome are present on the epidermis, is one cell thick. The cortex is about six cells ;_ At this stage of development, the pith and corti- ; enchyma are almost cubical. Figure 13E is a lon- nal section of the hypocotyl. The periderm is 7 formed by cell division in the phellogen, and irtex and epidermis are beginning to collapse. lith cells are elongated. Figure 13F is a radial A. Male flowers. B. Female flowers. section of the root 2 millimeters above the tip. The epidermal, cortical and pith cells are elongated. The cortex and pith cells contain some starch granules. Figure 13G is a Z-week-old seedling root tip with a typical root cap. The cells elongate progressively behind the apical meristem. An 8-month-old Texas persimmon stem had much more secondary tissue than the 13-week-old seedling. Figure 14 shows the third stem internode transection. The outer protective layer is a periderm of phellem cells produced by a phellogen in the outer cortex. The phloem and cambium are prominent because the stem was actively making radial growth when sampled. The xylem has two growth rings; the outer one is small, indicating a short period of radial growth and a larger inner growth ring. Figure 14B is a xylem transection. The rays are one cell wide, with scattered vessels. The xylem parenchyma and pith parenchyma (Figure 14C) con- tain abundant numbers of starch granules. The pith cells have fully lignified cell walls. Further development of mature Texas persimmon plants in the field is discussed in subsequent sections. Figure 2. Branches of flowering Texas persimmon plants at Georgetown, Texas, March 24, 1972. 13 Figure 3. Flowers of .' simmon at Georgeto April 15, 1971 (All Intact male. B. Male V away. C. Intact female. i‘ with side cut away. Figure 4. Fruit of T mon. A. Intact im (DEX). B. ture fruit (3X). i re 5. Transactions of an immature Texas persimmon it collected at Georgetown, Texas, April 21, 1969 (All v l. A. Fruit wall. B. Fruit center. C. Developing seed. Figure 6. Seeds of Texas persimmomf tact (2.8X). B. Split open (7.3X). I 16 igure 7. Seed of Texas persimmon. A. Histological section the seed coat and endosperm l192X). B. Seed coat and all endosperm l40X). C. Cotyledon tip of the embryo X). D. Cotyledon base and upper root of the embryo X). E. Root tip of the embryo and seed coat (40X). 17 Figure 8. Longitudinal anatomy of the Texas pa embryo (All 170X). A. Apical meristem and ball ledons. B. Middle of the root. C. Root tip. z, c 18 9. Seedling development of Texas persimmon. A. From i right, 2, 3, 4, 5, 6, 8, 10, 12 and 14 weeks (0.15X). B. 1- plants 18 to 24 inches tall. Figure 10. Surface views of a 13-week-old Texas persimmon seedling. A. Stem (50X). B. Cotyledonary node (4X). C. Mid root (SOX). D. Root tip (BX). 19 20 Figure 11. Transactions of a 70-millimeter-long G-week-old Texas persimmon seedling (All 170Xl. A. Hypocotyl. B. Forty to 50. millimeters above the root tip. C. Twenty to 30 millimeters above the root tip. D. Three to 10 millimeters above the root tip. Figure 12. Transections of a 13-week-old Texas persimmon seedling. A. Third internode above the cotyledons (322X). B. Hypocotyl (195X). C. Ten to 20 millimeters below the hypocotyl (195Xl. D. Thirty to 40 millimeters below the hypocotyl (288X). E. Sixty to 70 millimeters below the hypocotyl (288X). 21 Figure 13. Longitudinal sections of Texas persimmon seed- lings (A through F are from a 13-week-old seedling). A. Apical meristem (112Xl_.. B. Leaf a.nd lateral bud 1 milli- meter below the apical meristem (165Xl. C. Leaf and lateral bud 6 millimeters below the apical meristem (121 X). D. Stem 2 millimeters below the apical meristem (242Xl. E. Hypocotyl (170Xl. F. Root 2 millimeters above the tip (190Xl. G. Root tip from 2-week-old seedling (116Xl. 23 Figure 14. Stem transactions 40 to 50 millimeters above the cotyledonary node of an 8—month-old Texas persimmon plant grown in the greenhouse. A. Periderm, phloem, cambium and outer xylem (170X). B. Inner xylem (170Xl. C. Pith (330K). MORPHOLOGY OF THE STEM Types and Sizes of Plants Texas persimmon occurs both as individual plants i and as mottes. Seldom, however, does Texas persim- , mon occur either as the most abundant 0r the height- dominant species, except where other woody plants have been removed previously. The largest persim- k mon plant reported in Texas has a height of 26 feet, with a crown diameter of 31 feet; it is located on a ranch owned by Sam Barkley near Uavlde (Figure T». 15A).4 Other plants are taller, but not as large in diameter. Various kinds of Texas persimmon plants are ’ shown in Figure 15. Figure 15B shows a single-stem a plant about 9 feet tall near Georgetown. This type v of plant is a small proportion of most populations. y More typical multistemmed plants are shown in Figure l5C-—most have three to six stems and gen- erally grow 8 to 12 feet tall. Figure 15D shows a particularly large multistemmed plant about 18 feet tall near Llano. Figure 15E shows a motte of male Tex- as persimmon plants at Georgetown. All plants in this motte are males, with the same particular leaf and stem’ characteristics. The large plant in the cen- ter of the photograph may have been the original plant. In the field, nearly all Texas persimmon plants are multistemmed by the time they are 2 feet tall. On most plants, the main stem of the seedling has been either broken or chewed off by animals. The main stem of larger plants is generally killed either by fire or by mechanical and chemical control meth- ods. These plants become multistemmed from the release of several buds at the base of the stem or occasionally on the roots. New Stem Development The new stems begin elongation growth from apical buds, primarily in March and April at George- town. Also, a few new stems are produced after periods of abundant rainfall in late summer and fall ‘of some years. At Georgetown in 1971, new stems were initiated and elongated between March 15 and May 21. Twenty-five each of new male and female branches were tagged at the onset of elongation growth. There was no significant difference between sexes in length of shoots produced. The stem averaged 2.5,;.~4.3, 4.8 and 5.0 centimeters in length on April 1, April 15, May 5 and May 21, respectively. No further elongation growth occurred in 1971. Figure 16A shows the new stem tip in July after elongation growth had ceased. The leaves are dark green, and the lateral buds are prominent. Figure 16B shows a typical new stem, this one from a green- house plant. These stems are green and generally have abundant numbers of unicellular trichomes on leaves, buds and stems. The youngest and oldest ‘List of champion trees in Texas. 1971. Texas Forest Service, College Station, Texas 77843. leaves are smaller than those in the middle. In May or June the periderm forms, giving the new stems a gray color. Also, frequently one to three short, lateral branches are produced on the new stems, such as those shown on some new stems August 30, 1972 (Figures 16C and 16D). Older Stem Development The overall structure of male and female branches, other than new growth in August 1970 at George- town, is shown in Figure 17. The male branch in Figure 17A has many dried flower stalk remnants, but no flowers. Many small branches are only 1 to 3 centi- meters long. The leaves often are arranged in whorls from alternate buds on telescoped, short branches. The female branch (Figure 17B) also has many lateral twigs. As on the male plants, the leaves often appear in whorls on the alternate buds of the tele- scoped new twigs. The fruit occur primarily at the basal end of the twigs produced during the current season. Figure 18 shows typical Texas persimmon stem tissue in August 1970. In Figure 18A the new stem has already produced a gray periderm. The 0.6 centi- meter-diameter, or l-year-old stem, has a complete layer of slightly furrowed, gray periderm; this stem is further enlarged in Figure 18B. Stems 2 or more centimeters in diameter generally have patchy peri- derm as shown in Figures 18A and 18C. The furrowed periderm gradually peels off, leaving a relatively smooth surface. The larger stems 6 or more centi- meters in diameter generally have only smooth peri- derm. To document the diameter, length and branching of Texas persimmon, the researcher recorded the data from 10 branches on each of ten 5- and 10-foot tall plants. Half the plants were male and half female. Stem diameter was measured at the midpoint of the branch. The length was measured from the base of the stem either to the growing point or to the origin of the next branch. The total number of branches or remnants of branches, including the one leading to the next younger stem, was counted. Because the stem length was progressively more difficult to determine toward the base of the plant, a definite change in stem angle was considered as the criterion for branch- ing. On the 5-foot-tall plants, the number of living branches was recorded, as well as the total number of branches. The sexes did not differ in branching. Conse- quently, the data were combined (Table 7). The youngest stems were 0.2 to 0.3 centimeters in diameter for plants of both sizes. The stem diameter generally increased progessively from the tip to the base of the plant. At the plant base, the stem diameter was 5.9 and 11.2 centimeters for the 5- and 10-foot tall trees, respectively. The youngest stem was unbranched and 4.9 to 5.8 centimeters long. The older branches were 9.6 to 17.6 centimeters and 13.3 to 24.6 centimeters long on the 5- and 10-foot-tall plants, respectively. 25 Branching, except for the youngest increment, oc- curred more on the younger branches than near the base of the plant. Presumably some of the older branches had died and broken off, and many stubs were subsequently buried by radial branch enlarge- ment. Table 7. Texas persimmon stem diameter, length and number of lateral branches on 5- and 10-foot-tall trees at Georgetown, Texas Stem (increment Bramhes o" stem numbered from Stem Stem tip) diameter length Total Living1 (cm)' (cm) (Number) (Number) 5-foot trees 1 0.2 4.9 0.0 0.0 2 0.4 11.9 6.0 5.6 3 0.6 13.2 7.7 7.6 4 0.8 14.6 8.6 7.9 5 1.0 12.5 7.9 6.7 6 1.2 16.6 9.6 8.3 7 1.5 16.3 8.6 7.7 8 1.7 14.8 7.8 5.5 9 2.0 17.6 7.5 5.3 10 2.4 16.0 6.6 4.0 11 2.9 A 16.1 6.2 4..0 12 3.4 13.9 6.2 3.0 13 3.3 13.8 5.6 3.3 14 4.3 13.9 3.5 2.0 15 4.7 9Z6 4.6 3.8 16 5.5 12.0 3.0 2.0 17 5.9 15.5 4.0 2.0 10-foot trees 1 0.3 5.8 0.0 2 0.4 17.5 8.6 3 0.6 13.3 6.9 4 0.9 13.3 7.2 5 1.6 15.7 7.3 6 1.5 14.6 6.3 7 1.7 18.9 6.0 8 2.1 17.9 5.9 9 2.4 16.6 6.0 10 2.6 16.8 5.1 11 3.0 19.0 4.9 12 3.4 20.0 3.9 13 3.6 19.3 4.5 14 4.6 21.4 4.1 15 4.2 22.8 4.5 16 5.5 22.2 3.1 17 6.5 18.2 3.4 1s a 7.8 24.6 4.2 19 5.3 18.7 » 4.3 20 6.4 21.3 3.7 21 7.1 23.5 3_3 22 10.4 23.4 4.0 23 10.7 18.4 3.4 24 11.5 22.5 3.2 25' 11.2 23.5 3.5 iNumber of living branches was not recorded for 10-foot tall trees. 26 Figure 15. Texas persimmon plant forms. A. Largest recorded plant in Texas, near Uvalde, 26 feet tall, Sep- tember 1972. B. Single-stem plant, Georgetown, Texas, April 1971. C. Typ- ical multistemmed plant infestation, Georgetown, August 1972. D. Large multistemmed. plant, Llano, Texas, July 1970. E. Motte formation, Georgetown, August 1972. 28 Figure 16. New stem development of Texas persimmon. A. Stem tip, Georgetown, Texas, July 1971 (2X). B. Overall stem from a greenhouse plant (0.5X). C. Stem showing short-shoot branching, Georgetown, August 1972 (0.8Xl. D. Four stems showing pro- fuse lateral branching, Georgetown, August 1972 l0.3Xl. Figure 17. Branches of Texas persimmon, August 1970. A. Male branch. B. Female branch with fruit. ft xylem parenchyma. Figure 18. Stems of Texas persimmon, August 1970. A. New stem to 40-miIIimeter-diameter stem. B. A B-millimeter-diameter stem (1.7X). C. A 20-millimeter-diameter stem (2.8X). ANATOMY OF THE STEM New Stem Transections New stems are initiated in March and April and elongate until about mid-May at Georgetown. Radial i enlargement commences soon after production and generally extends until late June. Average daily tem- ' peratures between 65° and 75° F and abundant soil a moisture seem to favor new stem production and a radial enlargement. At first the new stems are green. At this stage, such as on April 7, 1970 (Figure 19A), the epidermis is one cell deep and has numerous trichomes. The cor- J tex is about l0 parenchyma cells deep, and the cells are almost spherical. The secondary phloem, cam- bium and xylem have formed a cylinder. The phloem 1 is about six cells deep. The xylem vessel elements occur in small radial rows among the thin-walled The pith parenchyma have thin walls and are devoid of visible stored food ma- terials. By May 26 (Figure 19B) a phellogen has formed in the outer cortex and has begun producing phellem cells to the outside, thus commencing periderm forma- tion. The cortical parenchyma are now slightly flat- tened, presumably from the pressure of growth of the phloem and xylem below and the periderm above. A tier of fibers and sclereids has matured between the inner cortex and the phloem. The xylem cells now have thick walls, and radial growth seems to have stopped. The enlarged xylem vessels are be- ginning to form in radial files, which is typical for the mature stem. The pith parenchyma have de- veloped thick walls (Figure 19C). By May 26 the stem has begun storing food ma- terial as starch granules in the xylem and pith paren- chyma. Radial enlargement ceases by July 8. On Octo- ber l2, the pith parenchyma are full of starch gran- ules. 29 One-Year-Old Stem Transections The l-year-old stern is the youngest stem produc- ing a new radial growth ring. The periderm is brown to gray and is 2 to 6 phellem cells deep; it forms a continuous tier around the stem. New phellem tiers appear to be produced near the surface of the stem each year for several years. The old phellem tiers shred off, giving the stem a slightly furrowed appear- ance. The cortex is present and is 6 to 10 parenchy- ma cells deep. Underneath is a tier of sclereids about 3 cells deep. The non-translocating phloem, com- prised largely of parenchyma cells, seems to build up for several years and remain alive. The translocating phloem is 6 to 8 sieve elements deep and is produced anew each year. The xylem and pith cells are lignified and contain many starch granules. Most radial stem growth occurs between April 1 and May 15, about the same time as new stem elon- gation. In 1969, radial growth occurred between March 24 and June 6. Stems sampled April 8 and May 20, 1969, were enlarging, with new growth layers 4 to l4 new xylem cells deep. In 1970, no new radial growth of l-year-old stems was observed in the samples collected. In 1971 radial growth occurred between April l and 15. On April 15, new stems had a growth ring about 15 new xylem cells deep. Radial growth of l-year-old stems occurred when the average air temperature was 65° to 73° F in 1969 and 1971. Radial enlargement probably is limited earlier in the year by low temperature and later by limited soil moisture. However, radial stem growth was not well correlated with rainfall that occurred at Georgetown during the 2-week and 2-month periods before measurement. Apparently radial growth is limited in late spring by a number of factors, rather than by soil moisture only. Older Stem Transections The older stems have a gray periderm (Figure 18). The outermost four to eight cells deep are phel- lem cells, which stain red with safranin (Figure 20A). Underneath is a tier of parenchyma, 6 to l0 cells deep, that stain green with fast green. These are pre- sumably phelloderm cells, which arise to the inside of the phellogen. A tier of sclereids 3 to 5 cells deep then develops; these cells seem to be part of the inner- most phelloderm. The phloem consists of non-translo- cating and translocating portions. The non-translocat- ing portion of the phloem consists largely of parenchy- ma with scattered small groups of sclereids. The trans- locating phloem consists largely of sieve tubes, com- panion cells and parenchyma. The translocating phloem comprises from about one-third to two-thirds of the total phloem thickness. The cambial zone is usually three cells deep. The xylem (Figure 20B) contains lignified fibers, parenchyma and vessel elements. The characteristics of the xylem are summarized in Table 8. The xylem is either semi-diffuse-porous to diffuse-porous with the 30 vessels, either solitary or in small groups, arranged S‘ radial files, with about 40 per square millimeter. T l. early wood vessels are generally only slightly larg and more numerous than the late wood vessels. Th perforations are simple (open). The longitudinal pair renchyma are vasicentric paratracheal, apotracheal? banded and marginal. The wood rays are simple andi generally unstoried; they are homogenous and general- ly two-seriated in stems 2 years old or more. ‘ The pith parenchyma are lignified. They general- ly contain abundant numbers of starch granules and" rhomboidal crystals until the stem is at least 2I,centi- meters in diameter. Phenolic-type materials become more abundant as the stem grows larger. In most ways, wood anatomy of Texas persimmon is similar to that of common persimmon. The main Table 8. Classification of stem wood (xylem) structure according to Commercial Timbers of the United States l3) I. Topography of wood — Semi-diffuse-porous to diffuse-porous ll. Vessels A. Arrangement of pores in summer wood- solitary or in radial rows of 2 to 5 with about 4O per mmz B. Size — 54i8 [.1 wide (tangentially) by 50:6 [.1 thick (radiallyll by 253132;; long; walls 3.3;; thick C. Spiral thickenings — absent D. Shape and arrangement of intervessel pits — round, min- ute, in transverse rows E. Nature of perforations — simple F. Inclusions 1. Tyloses — absent 2. Gum — present Ill. Tracheids — None found IV. Longitudinal parenchyma A. Arrangement- vasicentric paratracheal, 1- to 2-seriate; apotracheal-banded parenchyma very abundant, 1- to 2- seriate; marginal parenchyma 1- to 2-seriate B. Number of cells in wood parenchyma strands —- mostly 4, although 5 were occasionally observed C. Fusiform parenchyma cells are present D. Inclusions —— rhomboidal crystals V. Fibers A. Type — libriform fibers 13.6i4 ll in diameter by 711i95].1 long B. Thickness of walls — 3.9i0.6p VI. Wood rays A. Number per mm tangentially — 16.4i1.3# B Kind — simple C. Arrangement — unstoried D Seriation — mostly 2-seriated, some 1-seriated, very few 3-seriated E. Composition — homogeneous F. Size2 1. Average width - 24i'7 {.1 2. Average height — 221i73p lMeasured as individual pores. Single pores were slightly thicker than wide, whereas vessels in groups were usually wider than thick. 2Makes up about 22% of the wood volume. » Table 9. Texas persimmon stem transectional dimensions from samples collected near Georgetown, Texas Phloem Xylem ring thickness Non-trans- A. Stem Phellem Phelloderm Sclereid locating Translocating Cambium All other diameter thickness thickness thickness thickness thickness thickness New rings Pith ’ (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) . A 8 to 15 0.041 0.102 0.071 0.186 0.208 0.019 0.21 0.49 0.90 a 16 to 30 .035 .083 .096 .236 .201 .023 .30 .61 .94 . 40 .030 .073 .102 .321 .236 .026 .36 .80 80 .032 .077 .1 17 .370 .265 .028 .41 .80 Mean .035 .084 .096 .278 .228 .024 .32 .68 .92 difference, however, is that Texas persimmon xylem i is not storied, whereas xylem rays, parenchyma and v vessel elements o-f common persimmon are highly storied. Also, the vessel walls of Texas persimmon are thinner (about 3.3 microns thick) than those of com- .,mon persimmon (about 7.5 microns thick). _ Transectional tissue dimensions of four size classes l’ of stems 8 to 15, 16 to 30, 40 and 8O millimeters in di- ameter are presented in Table 9. The periderm con- isists of the phellem, which is on the outside of the phellogen and the phelloderm parenchyma on the in- side. The phellem and phellogen layers remain near- (Ily constant in thickness. The sclereid tier, xylem (growth rings, non-translocating part of the phloem , and translocating part of the phloem increase general- ly with increasing stem size. Pith, being a primary ‘tissue, is nearly constant in diameter in all sizes of stems. The periods of radial stem growth seem quite variable. Stems 1 centimeter in diameter were enlarg- ling radially May 11, June 8 and June 23 in l9'70 and on April 15, 1971; no radial enlargement was occurring _in the samples collected in 1969. In stems 2 to 8 centi- meters in diameter, radial enlargement occurred on a ay 20, June 6, July 8, August 9 and September .23, 1969: In 1970, new growth was occurring June 7 and 23; no samples were collected in 1971. Thus, adial growth in larger stems occurs in May through ptember in at least some years. This growth occurs ater than in stems 1 year old. , Figure 20 shows a series of transections of stems 9 to 8 centimeters in diameter, showing the seasonal , cle of radial growth. Figure 20A shows the stem ‘n-March l3, 1969, before growth occurred. Figure 0C shows a stern June 6, 1969, with an active cam- ium producing new phloem and xylem. Figure 20D is a transection of a stem collected July 8, 1969, show- ing the simultaneous production of new phloem and xylem, as well as a new phellogen with phellem to the outside and phelloderm to the inside. After the stern is 1 to 2 centimeters in diameter, these phellogens arise deep in the phloem, cutting off large areas of old phloem and periderm. The new phellogens begin at the margins of the old phellogens. Figure 20E shows the mature new phloem layer and phellogen just be- fore cleavage through the phellem. Usually the old phloem-periderm tier strips off the plant in July or later during dry weather. The stems appear smooth, once these phellogens form deep in the phloem and cause the thick layers topeel off (Figure 18C). It is different from common persimmon, which maintains a rough, blocky-type periderm throughout the life of the tree. Tangential and Radial Stem Sections Tangential views of the stem are presented in Figure 21. The phellem cells are more or less spherical (Figure 21A). Sieve-tube members, companion cells and a dense concentration of rays can be seen in the phloem in Figure 21B. The cambium has typical fusiform and ray initials (Figure 21C). The xylem has vessels, fibers and parenchyma (Figure 21D). All these cells are lignified. Several rhombic crystals are present. Views of radial sections of a stem 2 centimeters in diameter, which was harvested October 19, 1972, are shown in Figure 22. Figure 22A is the xylem. A large proportion is composed of rays. Figure 22B shows the area from the outer xylem outward, including the periderm. The rays progress outward to the sclereid tier. The parenchyma inside the periderm occur in files; presumably they arise inward from the phello- gen. 31 Y i if ; _. a i: 41» -- - f. 4* . 1, Q.‘ d’ n: 32 Figure 19. Transactions of Texas persimmon new stems of various sizes from Georgetown, Texas (All 170X). A. Epi- dermis to pith, April 1970. B. Periderm to outer xylem. May 26, 1970. C. Pith and inner xylem, May 26, 1970. t. fax... . 8 ma.) .. a w. pa.‘ ‘i, . 3.. a allow» ax . ._... at a5 x .. e .. teawewex» Q .8. w. H . ‘$.60... u§..,..,...,.....n i. .r~_e ,6 m¢§....f. w 33 imeter-diameter Texas persimmon stems from Georgetown, Xylem, July 7, 1970 (85X). C. June 6, 1969 (80X). D. July 8, . Transactions of 2- to 8-cent March 13. 1969 (82Xl. B. 1969 (39X). E. August 6, 1969 (82X). Figure 20 Texas. A. Figure 21. Tangential views of a 4-centimeter-diameter Texas persimmon stem collected at George- town, Texas, May 1971 (All 170X). A. Periderm. B. Phloem. C. Cambium. D. Xylem. 34 BUDS Stem Buds The overall branching habit of the Texas persim- i mon plant was discussed in the sections 0n stem 1 morphology and anatomy. Romberger (12) defined a bud as “an unextended, 1 partly developed shoot having at it.s summit the apical meristem which produced it. The latter is usually covered and protected by primordial leaves and by i cataphylls (scales) initiated by the meristem at some 2 earlier time. The subapical region of the meristem includes the internodes between primordial leaves and e cataphylls and makes up the mass of the tissue in the , central axis of the bud. Internodes in the subapical region are very short.” I In Texas persimmon, as in other species, the grow- ; ing apical bud produces the new stem, as represented g by a greenhouse-grown plant stem (Figure 23A). This 1 is not a true terminali bud; rather it is a lateral bud. Subsequent axillary or lateral buds are produced in Y the axil of the leaf at each node. The axillary buds at first are indistinct. By May 28 at Georgetown (Figure 23B), the new stem had fully elongated, and the axil- lary buds had become prominent. This stem and leaves were covered with trichomes. By October the Figure 22.. Radial views of a 2-centimeter-diameter Texas persimmon stem collected at Georgetown, Texas, October 19, 1972 (Both 82X). A. Xylem. B. Cambium, phloem and periderm. apical bud had formed on stems at Georgetown (Fig- ure 23C). The axillary buds seemed to be fully devel- oped. In January the buds were prominent, and all the leaves had abscised (Figure 23D). As the stem enlarges radially, the axillary buds subsequently become embedded in the periderm. The bud continues to produce a trace, as shown in a stem 30 millimeters in diameter (Figure 24A). The trace originates back at the pith. The bud does not seem to produce prominent primordial leaves. Rather, it appears to occur as a group of more or less undif- ferentiated cells (Figure 24B). The stem area at the bud is slightly raised. Root Buds Buds on roots are adventitious, in that they arise from potentially meristematic tissue, rather than from apical or axillary meristems. Presumably these buds arise from the phellogen, phloem or vascular cam- bium. Adventitious buds normally arise in two places. First, they arise along exposed edges of roots that have been cut off. Second, they arise from raised por- tions of roots at the point of emergence of smaller lateral roots. After the root has been cut off, these buds usually take 2 to 6 months to develop and begin producing new stems. 35 Sprouting Characteristics 0f Stems and Roots Texas persimmon readily sprouts from both stems and roots in the field. At Georgetown, stem and root sections were collected periodically in 1969 and 1970. On July 15, 1971, one of these plants, which had been pruned in October 1970, was photographed (Figure 25A). About four new stems, each approximately 8 inches long, had been produced at each stub. Other pruned plants responded similarly. In March 1969, 20 Texas persimmon plants, all about 9 feet tall, were cut off level with the soil surface at Georgetown. By August 27, 1970, they had sprouted profusely, primarily from the base of the stem. Two typical plants are shown in Figure 25B. As many as 20 new shoots were produced on the stem below the soil surface. Also, some short root sprouts had been produced by the plant at the left. The stems were as long as 15 inches. On August 30, 1972, the sprouts on most plants were 3 to 4 feet tall; however, one plant in the same area had stems 6 feet tall. There was no ap- parent reason for the difference in plant size. When cut off, Texas persimmon sprouts primarily in an in- complete apical-dominance pattern from the stem. However, plants readily sprout from the roots if all of the stem is removed or killed. Texas persimmon plants sprouted from roots at Georgetown, Llano, San Marcos and Sonora — all places inspected. Sprouts grew from both vertical tap- roots and horizontal roots. On vertical or steep-an- gling roots, several new stems arise near the cut end (Figure 26A). However, on horizontal roots, sprouts may arise all along the root, as shown by some roots collected at Llano in May 1973, after the stems had been severed by bulldozing 6 months earlier (Figure 26B). The sprouts are white, some with a black base. They produce unexpanded leaves until the apex emerges from the soil surface, as in Figure 26C. Subse- quently, normal green leaves are produced (Figure 26D). In the field, sprouts were found on roots as small as 6 millimeters in diameter. In the field, sprouting occurs naturally on many Texas persimmon plants. Apparently, plants that tend to sprout vigorously ultimately produce mottes, as shown in Figure 15E. Mottes are most evident in areas of shallow soil above rock. Several examples of sprouting in the field are shown in Figure 27. Figure 36 27A shows a root, found near Sonora, which was 1 inch in diameter and had two sprouts. The longest sprout was about 12 inches and was highly branched, presumably a result of grazing. Figure 27B shows a root obtained near Georgetown which was 1 inch in diameter and produced one large and two small stems. Figure 27C shows a plant at Georgetown, which was 7 feet tall and had produced a number of stems from horizontal roots. Figure 27D shows a number of new stems on the root of an uncut plant 26 feet tall, growing near Uvalde. In the greenhouse, sprouts can be produced ‘from root sections 4 inches long and about 0.75 inches or more in diameter, if they are brought in from the field and planted in flats containing a l:l mixture of Houston clay loam soil and sand. Figure 26C and 26D show such sprouts from roots collected at Georgetown on October l3 and December 28, 1972, respectively. The photographs were taken on April l3, 1973. Only about 5 to 10 percent of the root segments produced sprouts. Karr and Scifres5 earlier found similar sprout- ing from root segments 4 inches long and about 1 inch in diameter collected from Kerrville, Texas, August 25, 1972. They planted the root segments about l inch deep in clay loam soil from Kerrville in plastic pots 5 inches in diameter. The pots were placed outside in a lath house at College Station. By November 16, some shoots as long as 8 inches had been produced. About 60 percent of these root segments produced stems. All factors affecting sprouting are not clearly un- derstood. In a greenhouse study, three groups of eight Texas persimmon plants 1.5 years old and about 24 inches tall were cut off, each at 4 inches above the soil surface, 1 inch above the soil surface and l inch below the soil surface on January 7, 1972. The plants cut off 1 and 4 inches above the soil surface sprouted about equally well, producing 4.2 shoots per plant, which averaged 10.4 centimeters in length by August 24, 1972 (Figure 28). No sprouting occurred on plants cut o-ff l inch below the soil surface. This experiment was repeated with similar results. Perhaps lack of adequate reserve food supply in the roots prevented those greenhouse plants cut off below the soil surface fro-m producing sprouts on the roots. 5R. Karr and C. ]. Scifres. 1972. Unpublished information. Tex- as A8¢M Univ., College Station, TX 77843. Figure 23. Terminal stems of Texas persimmon. A. An elongating greenhouse plant stem (3X). B. A stem from Georgetown, Texas, May 1971 (3X). C. A stem from Georgetown, October 1972 (7.3X). D. A stem from Llano, Texas, January 1972 (3X). 37 Figure 24. Texas persimmon stem bud and trace. A’. Transection of a 3-centimeter-diameter stem with a bud trace (2.8X). B. Radial section of a 4-centimeter-diameter stem with a bud and trace terminus (82X). Figure 25. Resprouting of cut Texas persimmon plants at Georgetown, Texas. A. Production of new stems in July 1971 after branches had been cut off October 1970. B. Sprouting on August 1970 from stems cut off March 1969. At left, new stems from roots. The two large groups of stems in center have sprouted from cut-off stem bases. 38 Figure 26. Sprouting pattern of Texas persimmon roots. A. A steep-angling root at Georgetown, Texas, which had been cut off about 9 months earlier. B. Roots collected April 24, 1973, which had been cut off with a bulldozer at Llano, Texas about 6 months earlier. C. Sprouts in the underground stage from a 4-inch-long root section planted in soil in the greenhouse October 13, 1972, and photo- graphed April 13, 1973 (1.8X). D. Sprouts on a 4-inch-long root section planted in soil in the green- house December 28, 1972, and photographed April 13, 1973, showing the transition from the under- ground to the above-ground stage (1X). 39 40 Figure 27. Root sprouting of Texas persimmon on natural stands. A. Root 1 inch in diameter at Sonora, Texas, October 1970. B. Root 1 inch in diameter at Georgetown, Texas, May 1970. C. A 7-foot-tall plant at Georgetown, September 1970. D. A 26-foot-tall plant at Uvalde, Texas, September 1972. Figure 28. Sprouting of 1.5-year-old Texas persimmon plants in the greenhouse cut off in January and photographed August 1972. Cutting treatments (left to right) are 1 inch below, 1 inch above, 1 inch above, 4 inches above, and 4 inches above ground, respec- tively. LEAF MORPHOLOGY AND ANATOMY Location and Number of Production On a new stern, one leaf is produced at each node. - 0st new stems are initiated from about March 25 to pril l0 at Georgetown, and elongation is complete by I id-May. Subsequently, a few new stems may be pro- ‘uced after abundant rains, particularly in September Y. d October. The leaves expand to full length within ' weeks after emergence. At first they are light green and later turn dark green. Figures 16A, 16B, 16C and 16D show leaves on new stems. On May 5, 1973, 42 new stems of various sizes were collected at Llano and sorted into six groups ac- ording to number of nodes. The largest leaves had de- eloped in the middle of the stem (Table l0). Those oward both ends were smaller. The size differential as less marked on the stems with the fewest number .0 nodes than on those with more nodes. The leaves a ere roughly half as wide as long. Other than on new stems, leaves are produced pri- arily on the next two older stem increments. Very ew leaves are produced on older stems. These leaves ppear to arise in a whorled arrangement from a series f buds on telescoped stems. Most frequently, three o five leaves are produced on these foreshortened terns. able 10. Length of Texas persimmon leaves collected at Llano, exas, May 5, 1973 Number of nodes on stemz " ode position ginning f{0m 5 to 8 to 11 to 13 to 15 to 19 to . the tip 7 1O 12 14 17 21 (mm) (mm) (mm) (mm) (mm) (mm) 1 17 14 1O 8 1O 4 2 18 18 15 1O 14 8 3 19 19 18 13 17 1O 4 17 22 22 17 2O 14 5 12 22 23 18 2O 17 6 21 25 16 2O 2O 7 16 27 19 23 21 8 13 24 21 24 24 9 19 23 25 24 1O 16 19 24 25 11 11 14 23 26 12 11 21 28 13 8 2O 24 14 14 27 15 11 25 16 22 17 16 18 14 19 1O (8) (9) (10) (6) (7) (2) lMeasurements were begun at the first easily measured leaf about 0.25 inchbehind the apical meristem. yzThe number of stems measured in each group is in parentheses at the bottom of the table. Where two numbers of nodes were com- bined, the oldest node of the one with the most nodes was omitted. Where three numbers of nodes were combined, the node at either end of the one with the most nodes was omitted, while the old- est node of the middle one was omitted. Morphology The blade arises on a petiole about 2 millimeters long, which is usually covered with long, unicellular trichomes (Figure 29A). The leaf is simple and ob- lanceolate in shape (Figure 29B). The margin is en- tire, the base acute and the tip obtuse. The size and shape vary widely from plant to plant. Mature leaves vary from less than l centimeter to about 4 centimeters in length; most are 2 to 3 centimeters long and about twice as long as wide at the widest point. Either the blade is flat, or each lateral half rises slightly from the midrib outward to the margin. The margins frequently curl downward. Leaf veina- tion is net-like. The upper surface is glabrous (smooth), but usual- ly it has a few trichomes (Figures 29B and 30A). The lower surface has more trichomes, but the number may vary from almost none (Figures 29C and 30B), some (Figure 30C) to many (Figures 29D and 30D). Stomata occur only on the lower surface, as shown for the upper surface (Figure 30A) and the lower sur- face (Figures 30B and 30C), respectively. The guard cells have no adjoining subsidiary cells. Table ll shows the stomatal numbers on the lower surfaces of the leaves. These numbers were derived by viewing five leaves from five plants for each source tested in Table ll. Stomatal numbers at the leaf tip, middle and base in the lamina region were about the same (250 to 271 per square millimeter). Stoma concentra- tions on the greenhouse plants and on field plants with leaves l4 to 16 millimeters long were similar (219 to 230 per square millimeter). Large leaves from plants at Georgetown had more stomata (329 per square millimeter). Anatomy The petiole is generally about 2 millimeters long. A petiole transection from a leaf collected in May 1969 is shown in Figure 31A. A cuticle covers all ex- ternal surfaces. Several single-cell elongated trichomes are present. The vascular system lies in a bundle in the center of the petiole and is surrounded by cells Table 11. Concentration of stomata on Texas persimmon plants from the greenhouse and from the field at Georgetown, Texas Region of the leaf Source of lower surface leaves and Leaf collection dates length Tip Middle Base Mean (mm) (No./ (No./ (No./ (No. mm2) mm2) mm2) mm2) Greenhouse plant 16 216 234 206 219 Field plant March 23 to April 22 14 194 241 255 230 June 8 to July 26 26 339 339 310 329 Mean 250 271 257 41 that appear to be parenchyma. The xylem and phlo- em are both crescent-shaped, about seven cells deep and separated by a cambium. A series of leaf transections were made through the midrib of leaves collected periodically during the growing season; these are shown in Figures 31B through 31D. On April 22, most of the leaf cells have fully enlarged (Figure 31B). The palisade parenchyma are one to two cells deep, and the spongy parenchyma are compact. Most of the cells in the vascular bundle of the midrib have differentiated. However, the abaxial fibers and the xylem vessels have lignified only slightly. By May l1 (Figure 31C), most of the xylem and bundle fibers have more fully lignified. On July 8 (Figure 31D), the leaf has fully developed. with the xylem, phloem and fibers forming successive crescent-shaped layers. The xylem and bundle fibers have fully lignified, and the spongy parenchyma have more intercellular air spaces than previously. No further changes occurred during the year. Figures 31E and 31F show the transectional struc- ture of a leaf vein and margin as they appeared on leaves collected May l1, 1970. The vein has a struc- 42 ture similar to, but smaller than, that of the midrib. 1t also has a secretory cell and a prominent trichome. The margin curls downward (Figure 31F) and has a large crystal in the palisade and upper spongy paren- chyma. The leaf midrib and blade transections of greenhouse plants are similar to those produced in the field. However, the greenhouse leaf generally has less cuticle on the blade and slightly fewer tiers of xylem cells, phloem cells and bundle fibers in the midrib. Figure 32 shows a series of tangential sections in the lamina, taken progressively from the upper to lower leaf surface. Figure 32A is the upper epidermis, showing the shape of the irregularly shaped ground epidermal cells. Also, it shows the epidermal cell ar- rangement around the base of the trichomes. The trichomes have been cut off at the surface. Figure 32B is a view in the palisade parenchyma. A large crystal occurs at the upper left, and a secretory cell is at the lower left. A vein is shown at the lower right. Figure 32C is the spongy parenchyma area, with several crystals, secretory cells and veins. Figure 32D shows stomata in the lower epidermis. Figure 29. Leaf surface of Texas persimmon. A. Petiole (7.3X). B. Upper surface (4X). C. Lower surface with few trichomes (4X). D. Lower surface with many trichomes (4X). Figure 30. Leaf surface of Texas persimmon (photographs courtesy of Shirlee Meola). A. Upper lamina surface (220X). B. Lower lamina surface with no trichomes (220X). C. Lower lamina surface with a medium concentration of trichomes (22OX). D. Lower lamina surface with a dense concentration of trichomes (100X). 1'3 *,$,Q;:Q§~QQQ f Figure 31. Leaf transactions of Texas persimmon. A. Petiole, May 5, 1969 (82X). B. Midrib, April 22, 1970 (170X). C. Midrib, May 11, 1970 (17OX). D. Midrib, July 8, 1970 (170X). E. Vein, May 11, 1970 (243X). F. Margin, May 11, 1970 (243X). 46 Figure 32. Tangential leaf lamina sections of Texas persimmon (All 455X). A. Upper surface. B. Palisade parenchyma. C. Spongy parenchyma. D. Lower epidermis. ROOT MORPHOLOGY AND ANATOMY Morphology The morphology and anatomy of the Texas per- simmon seedling root has been discussed in the seed- ling section. This section concerns roots from older - plants. Several mature Texas persimmon plants were dug up with a bulldozer near Llano on July 1, 1971. Most - of this area was rocky, with shallow soil. Figure 33A f shows two interlocking plants with several large hori- 9 zontal roots. Each seems to have had a large taproot, which was broken off during the excavation operation. Figure 33B shows a plant with several large shallow roots. Figure 33C shows a plant with a long, large horizontal root. Apparently, where the soils are deep, the Texas persimmon plant produces a deep taproot. a However, on shallow sites, where Texas persimmon . frequently grows, it produces many shallow roots that A grow along the top of the underground rock layers un- til they can find rock-free areas to penetrate deeper , soil layers. Figure 33D shows short sections of several roots up to 2.25 inches in diameter which were dug at Georgetown on September 1, 1970. The root surface has furrows running parallel to the long axis of the root. The root is always black or dark brown, unless “exposed to the light, where it may be gray like the stem. No dark prominent heartwood is present unless the root is injured. Anatomy Typical Texas persimmon root transections are shown in Figure 34. Figure 34A shows a root 0.5 centi- meter in diameter, collected on March 24, 1970, before new radial growth had started. The root was covered with a series of semicircular layers of phellem. This was underlain by about five tiers of sclereids. The translocating phloem was about six cells deep. No cambial cell division was occurring at the time of collection. The xylem parenchyma were filled with starch, which serves as a reserve food supply. Figure 34B shows a root 2 centimeters in diameter, collected June 8, 1970, during an enlargement stage. The cam- bium was producing new xylem. The outer new xylem cells were not lignified. Figure 34C shows a root i2 centimeters in diameter, August 27, 1970, after radial growth had been completed. The translocating i phloiem was clear and 13 to 15 cells deep. The older phloem outside no longer had intact sieve elements, because they had been crushed during expansion i growth. The growth-ring formation in Texas persimmon roots, as in roots of" most arid and semiarid land . species, is erratic. Growth rings seem to form any time abundant moisture is available during a warm period. Consequently, incomplete and thin growth rings are common on most Texas persimmon roots. Typical tissue widths of five size classes of Texas persimmon roots from Georgetown are presented in Table 12. The periderm and sclereid layer thicknesses were between 0.12 and 0.25 millimeters and 0.12 to 0.17 millimeters, respectively, but showed no con- sistent size trends over the different size classes. The phloem was considered to be the areas between the sclereids and the cambium. The overall phloem was thicker in roots 31 to 80 millimeters in diameter than in roots 3 to 27 millimeters in diameter. The average xylem growth-ring thickness increased only slightly in progressively larger roots (0.78 to 0.90 millimeters). Table 12. Texas persimmon root tissue thicknesses of samples collected in 1969 and 1970 at Georgetown, Texas Xylem Root Periderm Sclereid layer Phloem growth-ring diameter thickness thickness thickness thickness (mm) (mm) (mm) (mm) (mm) 3 to 14 0.25 0.13 0.29 0.78 15 to 20 .20 .17 .28 .79 21 to 27 .12 .12 .34 .83 31 to 39 .21 .12 .47 .90 40 to 80 .15 .17 .61 .88 Typical tangential sections of roots of Texas per- simmon are presented in Figure 35. Figure 35A shows irregularly shaped phellem cells near the surface of the root. The layer with variously shaped sclereids is presented in Figure 35B. The outer phloem is com- prised largely of parenchyma with remnants of now non-translocating sieve elements (Figure 35C). Figure 35D shows translocating phloem, cambium and outer xylem. Two peripheral xylem vessels lie at the ex- treme left. Two rows of fusiform initials and some ray cambial initials of the cambium lie between the xylem vessels. The ray cells have large conspicuous nucleii. A number of fusiform cells occur from the center to the right side, which are not fully differenti- ated. A sieve tube member of the phloem occurs at the lower right. None of the cells contain starch granules. Figure 35E shows the inner xylem with vessels, fibers and parenchyma. Starch granules occur abundantly in the parenchyma. Figure 36 shows radial sections of a Texas persim- mon root. Figure 36A shows the phellem, phellogen, phelloderm, sclereid and outer phloem tiers. Figure 36B shows the sclereid tier, rays, non-translocating phloem, translocating phloem and cambium. Figure 36C shows the xylem with several rays. Crystals occur in the phloem and xylem parenchyma. 47 48 Figure 33. Main root systems of Texas persimmon at Llano, Texas, July 1971. A. Two interconnected plants with broken tap roots. B. A plant with an extensive lateral-root system. C. A plant that gained support and sustenance largely from one shallow lateral root. D. Short pieces of five roots up to 2.25 inches in diameter. Figure 34. Transections of Texas persimmon roots 0.5 to 2 centimeters in diameter (All 82X). A. April 21, 1969. B. June 8, 1970. C. August 27, 1970. 49 50 Figure 35. Tangential root sections of Texas persimmon (All 170X). A. Periderm. B. Sclereids. C. Outer phloem. D. Translocating phloem, cambium and outer xylem. E. Inner xylem. Figure 36. Radial root sections of Texas persimmon, November 1, 1970. A. Peri- derm, sclereids and outer phloem (170X). B. Cambium, phloem and sclereids (170X). C. Xylem (82X). 52 SEEDLING RESPONSE TO HERBICIDES Texas persimmon plants were grown from seed for about 10 months, when they were 10 t0 18 inches tall. The experiments were conducted from July l6, 1970, to March 29, 1971, and from March 1 to June 25, 1973. Tebuthiuron and karbutilate were sprayed only in the second experiment. Tebuthiuron was by far the most effective chemical for defoliating and killing Texas persimmon (Table l3). Picloram was about equal to tebuthiuron for de- foliating Texas persimmon. Only tebuthiuron killed a significant number of plants compared to plant deaths in the untreated pots. As of 1975 the new herbicide tebuthiuron has been applied to Texas persimmon in the field, but the re- sults have not been evaluated. DISCUSSION Texas persimmon is a difficult plant to work with. It grows slowly and erratically. A low percentage of seed germinate from fresh, intact fruit. Even washed seed germinate erratically and emerge over a several- week period when planted in a soil mixture in the greenhouse. None of the physical or chemical treat- ments tried increased percentage germination or caused uniform seedling development. A temperature of 80° F with adequate soil moisture seemed most favorable for producing new elongation growth. In the field few new plants are produced as seed- lings each year. Apparently Spanish goats, Rambouil- let sheep and whitetail deer digest and destroy seeds ,they feed on. Cattle and at least some nonruminant lanimals, such as the raccoon, scatter seeds in their fgfeces, and some of these seeds may subsequently germi- Enate. Apparently, the slow rate of development hinders l Table 13. Greenhouse Texas persimmon seedling response to herbi- cide sprays applied at 1 pound per acre Chemical Defoliation Dead plants (%l (%l 1. Amitrole 13 e 0 b 2. Atrazine 15 e 0 b 3. Bromacil 25 de 10 b 4. Cacodylic acid 28 de 18 b . 5. Dicamba 32 cde 10 b - 6. 2,4-D 54 bc 35 b 7. Dichlorprop 36 cde 20 b . s. 221-05 36 cde 22 b - 9. Fenac 21 de I 9 b 10. Karbutilate 28 de 12 b 11. MCPA 36 cde 22 b 12. Mecoprop 23 de 11 b 13. MCPB 32 cde 12 b S14. P_iclo_ram 81 a 37 b 15. Picloram + 2,4,5-T (1 =1)‘ 33 cde 14 b 16. Silvex 37 bcde 16 b A“ 7. Tebuthiuron 100 a 100 a .18. 2,4,5-T 44 bcd 23 b T19. Untreated 14 e 0 b Values followed by the same letter are not significantly different ‘ according to Duncan's multiple range test. the establishment of many seedlings in the field. Most seedlings probably desiccate before they can become established. Once established, however, the plants are very persistent. Texas persimmon may occur either as single- stemmed or as multistemmed individual plants or as mottes—most are multistemmed. These plants sel- dom are the most numerous component of the woody vegetation in natural stands. However, Texas persim- mon may become dominant after other species have been controlled. Most control measures remove only some or all of the above-ground portions of the stem. When the upper stems are cut off, normally about four new stems are produced just below the cut. When cut off at the soil line, the plant may produce as many as 20 vigorous stems at the base of the stem and on the root. When cut off at the upper root, the remaining roots can produce few to many new shoots. These shoots produce leaves much reduced in size on underground nodes; aboveground leaves are normal. Surfaces of Texas persimmon vary widely. New stems are generally highly pubescent, while still hav- ing an epidermis. Subsequently, the stem exterior is slightly furrowed until 1 to 2 centimeters in diameter as a result of multiple shallow phellogen formation during radial enlargement. Ultimately, however, the stem usually becomes somewhat smooth, because the phellogens form large, continuous layers that kill ex- tensive areas of the outer periderm and phloem, which strip off in sheets in late summer and fall. Leaves may have few to many trichomes ,particularly on the under surface. Herbicides have generally not been effective for controlling Texas persimmon. Hoffman (5) has found that 16 pounds of 2,4,5-T ester in enough diesel oil to make 100 gallons of solution, applied to the point of runoff on the cut-off stumps, will kill a large percent- age of plants in the field in July and August. Broad- cast applications of herbicides generally kill few if any Texas persimmon plants, unless the rate of herbicide is so high that desirable forage plants are unduly injured. In unpublished results, this researcher found that pic- loram as the potassium salt in granules killed in- dividual Texas persimmon plants at Marble Falls when applied at 4 to 6 pounds per acre in the fall. In this greenhouse study, picloram and the new herbi- cide tebuthiuron seem to be the most effective for controlling Texas persimmon. However, tebuthiuron probably will kill grass and broadleaf species if ap- plied as a broadcast treatment. ACKNOWLEDGMENTS This research was a cooperative undertaking of the Agricultural Research Service, U. S. Department of Agriculture, and The Texas Agricultural Experiment Station, College Station, Texas 77843. The author appreciates the technical assistance of W. T. McKelvy and T. E. Riley, and the use of land 53 _. _ . ._. . .__,___._.._..._.v._._.._.._.p..___..-l..-._, l l in Texas provided by Sam Barkley, Uvalde; Mrs. Ann Etta Hall, Llano; Fred S. Horlen, Llano; Leo B. Mer- rill, Sonora; and D. B. Wood, Georgetown. Animals and facilities for feeding studies were provided at Tex- as A8cM University, College Station, Texas, by R. L. Lawson, Richard M. Robinson and A. M. Sorensen. Horace R. Burke identified the insects, and Shirlee Meola provided scanning electron micrographs of some leaf surfaces. Herbicides were supplied by -Am- chem Products, Inc., Ambler, Pennsylvania; The Ansul Company, Marinette, Wisconsin; The Dow Chemical Company, Midland, Michigan; E. I. duPont de Ne- mours 8c Company, Inc., Wilmington, Delaware; Elan- co Chemical Company, Greenfield, Indiana; FMC Corporation, Middleport, New York; Geigy Chemical Corporation, Ardsley, New York; and Velsicol Chem- ical Corporation, Chicago, Illinois. LITERATURE CITED 1. Bouse, L. F., and R. W. Bovey. 1967. A laboratory sprayer for potted plants. Weeds 15:89-91. 2. Britton, N. L. 1908. North American trees. Henry Holt and Co., New York. 894 pp. Brown, H. P., and A. J. Panshin. 1940. Commercial tim- bers of the United States. McGraw-Hill Book Co., New York. 554 pp. 4. Hamilton, W. J., Jr. 1946. The black persimmon as a summer food of the Texas armadillo. J. Mammal. 27:175. $0 5. Hoffman, G. O. 1972. Texas persimmon — a pesky problem. Tex. Agr. Prog. l8(l):8-9. 6. Martin, A. C., and W. D. Barkley. 1961. Seed identii tion manual. Univ. of Calif. Press, Berkeley. 221 pp. 7. Metcalfe, C. R., and L. Chalk. 1957. Anatomy of dicotyledons. Oxford Univ. Press. London. 1500 pp. r s. Meyer, R. E., M. o. Merkle and c. R. Bythewood. -‘ Texas persimmon fruit inhibition of seedling growth. .1 Agri. Exp. Sta. PR—2820. In Brush Res. in Tex.—l pp 74-76. 5 9. Meyer, R. E., H. L. Morton; R. H. Haas, E. D. Robi { and T. E. Riley. 1971. Morphology and anatomy of ho mesquite. USDA Tech. Bul. 1423. 186 pp. 10. Meyer, R. E., T. E. Riley, H. L. Morton and M. G. Merkl 1969. Control of whitebrush and associated species herbicides in Texas. Tex. Agr. Exp. Sta. MP —930. 18 1l. Panshin, A. J., and Carl (leZeeuw. 1970. Vol. I. Textbotli of wood technology. 3rd Ed. McGraw-Hill Book Co., Ned York. 705 pp. 12. Romberger, J. A. 1963. Meristems, growth, and develop; ment in woody plants. USDA For. Serv. Tech. Bul. 1293. 214 pp. 13-. Sass, J. E. 1961. Botanical microtechniqixe. Iowa State Univ. Press. Ames. 228 pp. 14. U. S. Forest Service. 1948. Woody-plant seed manual. USDA Misc. Publ. 654. 416 pp. 15. Vines, R. A. 1960. Trees, shrubs, and woody vines of the southwest. Univ. Tex. Press. Austin. 1104 pp. 16. Wilson, B. V. 1969. Annual carbohydrate storage of the Texas persimmon Diospyros rexana. Master of Sci. Thesis. Southwest Tex. State Univ., San Marcos, TX. 19 pp. 17. Young, L. J., Bobby Wilson, James Tabler and Richard Ellis. 1969. A study of the ecology and control of the Texas persimmon Diospyros texana. In Noxious brush and weed control Res. Rpt. (Tex. Tech. Univ.), Spec. Rpt. N0. 33. International Center for Arid and Semi-arid Land Studies. pp. 90-91. GLOSSARY“ Apical meristem-—A group of dividing cells at the tip of root or shoot that produce the precursors of the primary tissues of root or shoot. Bark—A1l tissues outside the cambium in woody plants. Bud primordium —The bud in its earliest stage of development (differentiation). Bundle sheath—A layer or layers of cells, usually parenchyma, enclosing a vascular bundle. Bud trace— The cylinder of lignified parenchyma in the xylem extending from the origin out to the base of the present bud in the stem. Cambium ——A persistent layer of dividing cells which gives rise to the radial enlargement of the secondary xylem and secondary phloem. Companion cell—A specialized parenchyma cell in the phloem associated with a sieve-tube member. Cortex — The primary ground-tissue region between the vascular system and the epidermis. . Cotyledon — One of the first two leaves of the embryo as found in the seed. Cuticle—A layer of waxy material, cutin, on the outer wall of epidermal cells. Endocarp—The inner layer of the fruit wall developed from the ovary wall. Endosperm-The nutritive and protective tissue formed within the embryo sac of the seed. Epidermis—The outer layer of cells primary in origin. Exocarp—The outer layer of the fruit wall developed from the ovary wall. Fiber-An elongated tapering cell with a more or less thick secondary wall usually containing lignin. “Some of the definitions apply specifically to Texas persimmon. 54 Fusiform initial—An elongated cell with wedge-shaped ends in the cambium that gives rise to the elongated cells in the radially enlarging (secondary) xylem and phloem. Hypocotyl—The portion of an embryo or seedling below the cotyledons and above the primary root. Inch—A measure of length equal to 2.54 centimeters or 25.4 millimeters. Lamina—The blade or expanded part of a leaf. Leaf—The thin expanded organ borne laterally on the stern including the blade, or lamina, and petiole. Leaf primordium—The leaf in the earliest stage of develop- ment (differentiation). Mesocarp-The middle layer of the fruit wall developed from the ovary wall. Midrib—The central or main vein of a leaf. Non-translocating phloem—The outer region of the phloem containing parenchyma and fibers that does not participate in the movement of foods. Palisade parenchyma—Elongated, thin-walled cells in the leaf arranged perpendicular to the surface under the upper epidermis. Parenchyma — Living cells of primary or secondary origin varying widely in shape, wall thickness and size usually concerned with photosynthesis, storage or excretion of various ma- terials, wound healing and origin of adventitious structures. Periderm-Secondary protective tissues including the phellen and phelloderm derived from the phellogen which replaces the epidermis in stems and roots. Petiole—The supporting foot-stalk of a leaf. Phellem-—Non-living cells in the periderm formed to the out- side by the phellogen. Phelloderm —A tissue of thin-walled cells in the periderm formed to the inside by the phellogen. Phellogen-The cork cambium or dividing layer of cells which forms the outer protective tissue (periderm) of stems and roots consisting of phellem to the outside and phelloderm a t0 the inside. * Phloem —The principal food-conducting tissue of the plant which is composed of companion cells, sieve tube members, p35’ parenchyma and fibers. fiéPith-The primary ground tissue in the center of a stem or root comprised of parenchyma. :5 Ray-A panel of tissue formed by the cambium and extending radially in the secondary xylem and secondary phloem of the stem and root. 5” Ray initial—A rectangular cell in the cambium that gives rise to ray cells of the xylem and phloem. Root-The descending axis of the plant without nodes or internodes developing underground and absorbing moisture and nutrients from the soil. Sclereid— A lignified, thick-walled cell with many pits varied in shape but typically not much elongated. Secretory cell—A living cell specialized with regard to secretion of one or more usually organic substances. Seed—The ripened ovule consisting of the embryo and its proper coats. Letters Identification AM Apical meristem BP Bud primordium i BS Bundle sheath BT Bud trace CA Cambium pi CC Companion cell CO Cortex CR Crystal j ‘ CT Cotyledon i; EN Endocarp § EP Epidermis ES Endosperm EX Exocarp FB Fiber Fl Fusiform initial HP Hypocotyl LF Leaf LP Leaf primordium _ ME. Mesocarp NP‘ Non-translocating t phloem PD Phelloderm PG Phellogen PH '_i Phloem Sieve tube member—An elongated cell in a sieve tube of the translocating phloem. Spongy parenchyma— Leaf parenchyma with intercellular spaces lying between the palisade parenchyma and the lower epidermis. Stem—The ascending axis of the plant developing above ground with nodes, internodes and leaves. Stoma (pl. stomata)—A minute opening between two guard cells in the epidermis which allows gaseous interchange between the atmosphere and the internal cells of the leaf. Translocating phloem—-The inner region of the secondary phloem containing sieve tube members and companion cells that translocate the food materials in the plant. T richome—An outgrowth of the epidermis, variable in shape, size and function usually referring to hairs. Vascular bundle — A strand-like part of the vascular system com- posed of xylem and phloem in the stem and leaf. Vein—A strand of vascular and supporting tissue in the leaf. Xylem-—The principal water and mineral conducting tissue in the plant. The secondary xylem (wood) is also important for support and food storage. It is comprised of vessel mem- bers, parenchyma and fibers. Xylem vessel-A tube-like series of elongated vessel members with the common walls having open ends. PHOTOGRAPH SYMBOL IDENTIFICATION LIST Letters Identification Pl . Pith PL _ Phellem PP Palisade parenchyma PT Petiole RA Ray RC Root cap Rl Ray initial RP Ray parenchyma RT Root SC Sclereid SD Seed SE Secretory cell SG Starch granule SM Sieve tube member SO Stoma SP Spongy parenchyma ST Stem TC Trichome TP Translocating phloem VB ~ Vascular bundle VE Vein VS Xylem vessel XP Xylem parenchyma XY Xylem The Texas Agricultural Experiment Station-J. E. Miller, Director, College Station, Texas 2l/2M—9-74 v- ‘ l."