c» QC OF THE UNIVERSITY or ILLINOIS 580. 5 FB FLORA OF GUATEMALA PART II: GRASSES OF GUATEMALA JASON R. SWALLEN BAMBOOS F. A. McCLURE FIELDIANA: BOTANY VOLUME 24, PART II Published by CHICAGO NATURAL HISTORY MUSEUM NOVEMBER 10, 1955 FLORA OF GUATEMALA PART II: GRASSES FLORA OF GUATEMALA PART II: GRASSES OF GUATEMALA JASON R. SWALLEN Head Curator, Department of Botany United States National Museum BAMBOOS F. A. McCLURE United States Department of Agriculture FIELDIANA: BOTANY VOLUME 24, PART II Published by CHICAGO NATURAL HISTORY MUSEUM NOVEMBER 10, 1955 isNtj -t r PRINTED IN THE UNITED STATES OF AMERICA BY CHICAGO NATURAL HISTORY MUSEUM PRESS r CONTENTS Genera Included in Volume 24, Part II PAGE PAGE Aegopogon 12 Eriochloa 129 Agrostis 14 Eriochrysis 131 Andropogon 17 Euchlaena 133 Anthephora 28 Festuca 133 Aristida 31 Gigantochloa 139 Arthraxon 37 Glyceria 144 Arthrostylidium 38 Gouinia 144 Amndinaria 41 Guadua 146 Arundinella 44 Gymnopogon 157 Avena 47 Gynerium 158 Axonopus 47 Hackelochloa 158 Bambusa 52 Heteropogon 161 Bouteloua 61 Hierochloe 161 Brachiaria 65 Hilaria 163 Brachypodium 66 Homolepis 163 Briza 66 Hymenachne 166 Bromus 68 Hyparrhenia 169 Calamagrostis 70 Ichnanthus 170 Cathestecum 72 Imperata 177 Cenchrus 76 Isachne 178 Chaetium 78 Ischaemum 180 Chloris 80 Ixophorus 180 Chusquea 86 Jouvea 182 Cinna 93 Lamarckia 184 Coix 95 Lasiacis 184 Cryptochloa 96 Leersia 191 Cymbopogon 97 Leptochloa 193 Cynodon 97 Leptocoryphium 196 Dactyloctenium 98 Lithachne 197 Dendrocalamus 101 Lolium 200 Diectomis 102 Luziola 200 Digitaria 105 Manisuris 201 Distichlis 110 Melinis 203 Echinochloa 1 12 Melocanna 204 Echinolaena 114 Merostachys 206 Eleusine 115 Mesosetum 209 Elyonurus 116 Microchloa 210 Eragrostis 116 Muhlenbergia 213 PAGE Olyra 224 Oplismenus 226 Orthoclada 228 Oryza 231 Panicum 233 Paspalum 269 Pennisetum 296 Pentarrhaphis 300 Pereilema 302 Pharus 304 Phragmites 308 Phyllostachys 308 Piptochaetium 316 Poa 318 Polypogon 320 Pseudechinolaena 320 Rhynchelytrum 323 Saccharum 326 Sacciolepis 326 Schizostachyum 328 Setaria 331 Setariopsis 338 Sorghastrum 338 Sorghum 342 Spartina 344 Sporobolus 345 Stenotaphrum 349 Stipa 350 Streptochaeta 353 Thrasya 354 Trachypogon 356 Trichachne 359 Triniochloa 359 Tripsacum 362 Trisetum 364 Tristachya 368 Triticum 370 Uniola 370 Zea 373 Zeugites 373 Emendations . . . 377 Index . 378 VI LIST OF ILLUSTRATIONS TEXT FIGURES PAGE 1. Aegopogon tenellus 13 2. Andropogon saccharoides 25 3. Andropogon virginicus 29 4. Anthephora hermaphrodita 30 5. Aristida adscensionis 32 6. Aristida ternipes 36 7. Arthraxon quartinianus 37 8. Arundinaria simonii 42 9. Arundinella confinis 46 10. Axonopus compressus 51 11. Bambusa vulgaris 58 12. Bouteloua curtipendula 63 13. Brachypodium mexicanum 67 14. Briza minor 69 15. Calamagrostis vulcanica 73 16. Cathestecum erectum 75 17. Cenchrus brownii 77 18. Cenchrus echinatus 77 19. Chaetium bromoides 79 20. Chloris radiata 83 21. Chloris virgata 85 22. Chusquea simpliciflora 92 23. Cinna poaeformis 94 24. Coix lacryma-jobi 95 25. Cynodon dactylon 99 26. Dactyloctenium aegyptium 100 27. Dendrocalamus strictus 103 28. Diectomis fastigiata 104 29. Digitaria leucites 107 30. Digitaria sanguinalis 109 31. Distichlis spicata Ill 32. Echinochloa colonum 113 33. Echinochloa cruspavonis 113 34. Eleusine indica 117 35. Eragrostis cilianensis 120 36. Eragrostis ciliaris 122 37. Eragrostis glomerata 125 38. Eragrostis hypnoides 126 39. Eriochrysis cayennensis 132 vii 40. Euchlaena mexicana 135 41. Festuca breviglumis 137 42. Festuca dertonensis 138 43. Gigantochloa verticillata 143 44. Gouinia guatemalensis 145 45. Guadua aculeata 149 46. Gymnopogon spicatus 159 47. Hackelochloa granularis 160 48. Heteropogon contortus 162 49. Hierochloe mexicana 164 50. Hilaria cenchroides 165 51. Homolepis aturensis 167 52. Hymenachne amplexicaulis 168 53. Ichnanthus pallens 174 54. Ixophorus unisetus 181 55. Jouvea straminea 183 56. Lamarckia aurea 185 57. Lasiacis divaricata 188 58. Leersia hexandra 192 59. Leptochloa filiformis 194 60. Leptocoryphium lanatum 198 61. Lithachne pauciflora 199 62. Luziola peruviana 202 63. Melinis minutiflora 203 64. Melocanna baccifera 205 65. Merostachys pauciflora 208 66. Mesosetum stoloniferum 211 67. Microchloa kunthii 212 68. Muhlenbergia breviculmis 216 69. Muhlenbergia calcicola 216 70. Muhlenbergia orophila 222 71. Olyra latifolia 225 72. Oplismenus setarius 229 73. Orthoclada laxa 230 74. Oryza sativa 232 75. Panicum geminatum 247 76. Panicum maximum 254 77. Panicum purpurascens 261 78. Paspalum conjugatum 278 79. Paspalum urvillei 295 80. Pennisetum setosum 299 81. Pentarrhaphis scabra 301 82. Pereilema crinitum 303 83. Pharus latifolius 305 84. Pharus parvifolius 307 85. Phragmites communis 309 86. Phyllostachys bambusoides 313 87. Piptochaetium fimbriatum 317 88. Poa venosa 321 89. Polypogon elongatus 322 90. Pseudechinolaena polystachya 324 91. Rhynchelytrum roseum 325 92. Saccharum officinarum 327 93. Sacciolepis myuros 328 94. Schizostachyum pseudolima 330 95. Setaria paniculifera 335 96. Setaria tenacissima 335 97. Setaria vulpiseta 337 98. Setariopsis auriculata 339 99. Sorghastrum brunneum 341 100. Sorghum halepense 343 101. Sporobolus poiretii 347 102. Stenotaphrum secundatum 351 103. Streptochaeta spicata 354 104. Thrasya campylostachya 355 105. Trachypogon secundus 358 106. Trichachne insularis 360 107. Triniochloa stipoides 361 108. Trisetum irazuense 367 109. Tristachya avenacea 369 110. Triticum aestivum 371 111. Uniola pittieri 372 112. Zea mays 374 113. Zeugites'mexicana 375 Grasses of Guatemala INTRODUCTION The grasses of Guatemala were treated by A. S. Hitchcock ("The Grasses of Central America," Contr. U. S. Nat. Herb. 24: 557-762. 1930). This account was based primarily on the early collections of Heyde and Lux, Thie'me, and John Donnell Smith, and those of A. S. Hitchcock in 1911. In recent years P. C. Standley and Julian A. Steyermark have collected extensively in Guatemala, adding many grasses to the known flora, including a relatively large number of new species. Phytogeographically, British Honduras is similar to the Pete'n region of Guatemala. The grasses of this country are included, although there are relatively few that are not found in Guatemala. Recent important collections are those of H. H. Bartlett, Percy Gentle, and C. L. Lundell. The present treatment includes 120 genera and 455 species, both native and introduced. The large number of species is due, at least in part, to the diverse habitats, ranging from tropical lowlands to subalpine meadows. The largest genera are Panicum, Paspalum, and Andropogon, accounting for approximately one-third of the grass flora. The arrangement of the genera and species is alphabetical, to conform to the original plan of the Flora. While there are certain advantages of this style, closely related genera and species may be widely separated in the text. The synonymy has been restricted to name-giving synonyms and others which are important from the historical point of view. Com- mon names have been included as far as possible. Many of the illustrations have been taken from the Manual of Grasses of the United States and the Manual of Grasses of the West Indies by A. S. Hitchcock. The others have been prepared by Mr. Samuel H. Grove, Jr., of Chicago Natural History Museum, and Mr. John Ihle, formerly of the same institution, except as otherwise credited. 2 FIELDIANA: BOTANY, VOLUME 24 The author is indebted to Dr. F. A. McClure, who has kindly prepared the manuscript for the Bambuseae. GRAMINEAE1 Flowers perfect (rarely unisexual) , arranged in spikelets consisting of a shortened axis (rachilla) and 2 to many 2-ranked bracts, the lowest two (glumes, rarely one or both obsolete) empty, each succeeding one or more (lemmas) bearing in their axils a single flower (one to few of the lower lemmas sometimes barren, and the upper one or more often reduced and sterile), and between the flower and rachilla a 2-nerved bract (palea), the lemma, palea, and included flower con- stituting the floret; stamens 1 to many, usually 3, with delicate filaments and 2-celled anthers; pistil 1, with a 1-celled 1-ovuled ovary, 2 (rarely 1 or 3) styles, and usually plumose stigmas; fruit a caryopsis, the grain rarely free from the pericarp. Herbaceous or sometimes woody plants with round or somewhat flattened, hollow or solid stems (culms), and 2-ranked, usually parallel-veined leaves consisting of a sheath which envelopes the culm, a blade, usually flat, and between the two on the inside a membranaceous or hairy appendage (ligule), this rarely obsolete. Stems woody (see also Olyra and Lasiads); leaf blades petiolate, ultimately dis- articulating from their sheaths; culm sheaths and their blades markedly different from the sheaths and blades of functional leaves in size and shape. Native or exotic bamboos.2 Native bamboos. Flowering material available. Inflorescences indeterminate3 Guadua. Inflorescences determinate.4 Spikelets several-flowered Arthrostylidium. Spikelets with but one functional floret. Spikelets terminating above in a rudiment Merostachys. Spikelets terminating above in a functional floret Chusquea. Flowering material not available (field key). Culm internodes not hollow Chusquea. Culm internodes hollow. Lower main branches with some twigs reduced to spines Guadua. All branches unarmed. References: Manual of Grasses of the United States, U. S. Dept. Agr. Misc. Pub. 200. 1951 (revised). Manual of Grasses of the West Indies, U. S. Dept. Agr. Misc. Pub. 243. 1936. North American Flora 17 (5, 6) 1935; (7) 1937; (8) 1939. Flora of Panama: Gramineae, Ann. Mo. Bot. Card. 30: 104-280. 1943. 2 The scope of this key is limited to those bamboos known to occur in Guate- mala. 3 New branches (pseudospikelets) may arise from buds in the axils of the bracts found just below each spikelet. 4 All axes of the inflorescence complete their growth at once; no new branch- ing takes place within the inflorescence. SW ALLEN: GRASSES OF GUATEMALA 3 Culm sheath1 blades appressed to the culm Arthrostylidium. Culm sheath blades reflexed Merostachys. Exotic bamboos. Flowering material available. Stamens 3; leaf blades typically tessellate- veined. Inflorescences determinate, racemose or paniculate, with long-pedicelled, not crowded spikelets, the pedicels subtended by inconspicuous, often obsolete bracts Arundinaria. Inflorescences indeterminate, sometimes more or less densely aggregated in heads, with short-pedicelled spikelets, the pedicels subtended by conspicuous bracts Phyllostachys. Stamens 6; leaf blades not typically tessellate- veined. Palea of terminal functional floret bearing a slender, bristle-like rachilla segment hidden in its dorsal sulcus Schizostachyum. Palea of terminal functional floret not bearing a bristle-like rachilla segment. Palea never keeled Melocanna. Palea 2-keeled in lowermost functional florets. Stamens monadelphous or with flattened filaments connate. Gigantochloa. Stamens free, the filaments filiform. Rachilla segments abscissile, the spikelet disarticulating readily; fruit a sulcate caryopsis with a thin, adnate pericarp . Bambusa. Rachilla segments not abscissile except below the first lemma, the spikelet not disarticulating; fruit a globose nut, with a thick, separable pericarp Dendrocalamus. Flowering material not available (field key). Rhizome indeterminate, slender, wide-ranging; leaf blades typically tes- sellate-veined. Branch complement with one strongly dominant central branch, this either solitary or flanked by one to several pairs of progressively shorter and more slender ones Arundinaria. Branch complement typically consisting of two somewhat unequal branches, with sometimes a third, much smaller between them. Phyllostachys. Rhizome determinate, thick, short; leaf blades not typically tessellate- veined. Rhizome neck (the slender, terete, budless, rootless, horizontal structure basal to the rhizome proper) several times as long as the rhizome proper, up to 1 meter or more in length Melocanna. Rhizome neck much shorter than the rhizome proper. 1 Throughout the part of this key that deals with bamboos, and in the de- scriptions of the bamboos that follow, wherever the term "culm sheath" appears it refers to examples of these structures taken from the lower part of the culm, usually from some node between the fifth and the tenth; exceptions are clearly indicated. 4 FIELDIANA: BOTANY, VOLUME 24 Culm sheath blade narrow, reflexed. Branch complement with numerous, slender, subequal branches. Schizostachyum . Branch complement with one strongly dominant central branch, this either solitary or flanked by several pairs of progressively shorter, more slender ones Gigantochloa. Culm sheath blade broadly triangular, appressed to the culm. Leaf blades in the lower part of the culm pubescent on both surfaces. Dendrocalamus. Leaf blades pubescent throughout lower surface only Bambusa. Stems mostly herbaceous, or woody only at the base (woody throughout in Olyra latifolia, and most species of Lasiacis); leaf blades usually not petiolate, and not disarticulating from their sheaths; culm sheaths and their blades not markedly different from the sheaths and blades of the functional leaves. Spikelets 1- to many-flowered, the reduced florets, if any, above the fertile florets (except in Hierochloe; lower florets empty in Uniola); articulation usually above the glumes (below the glumes in Zeugites, Cinna, Polypogon, Oryza, and Leersia). Spikelets in groups of 2-5, the groups racemose along a common axis, falling entire. Plants annual. Groups of spikelets nodding; first glumes relatively thin, not forming an involucre Aegopogon. Groups of spikelets erect; first glumes broad, indurate, forming a pitcher- shaped involucre around the spikelets Anthephora. Plants rigid; perennial Hilaria. Spikelets solitary or paired, not arranged in groups along a common axis. Lemma with a long much-contorted awn, the awns becoming tangled and remaining attached at the apex of the axis; broad-leaved perennials. Streptochaeta. Lemma awnless, or if awned, the awn straight or geniculate, never con- torted or becoming tangled. Spikelets unisexual. Plants monoecious. Spikelets in somewhat distant pairs along the main branches, one of each pair sessile, pistillate, the other long-pedicellate, staminate, much smaller than the pistillate spikelet; stamens 6 Pharus. Spikelets not in pairs as above; stamens 2 or 3. Glumes wanting, only the lemma and palea present; aquatic grasses with the staminate and pistillate spikelets in separate inflores- cences Luziola. Glumes present; terrestrial, usually forest grasses. Panicles large, terminal, the pistillate spikelets on the upper branches and toward the ends of the lower ones, the staminate on the lower part of the lower branches Olyra. Panicles small, axillary, or terminal and axillary, the terminal when present usually wholly staminate. SWALLEN: GRASSES OF GUATEMALA 5 Fruit roughly triangular, inflated, gibbous; panicles axillary, composed of 1 terminal pistillate spikelet, and a few stam- inate spikelets below it Lithachne. Fruit subcylindric; panicles terminal and axillary. Fruit raised on the enlarged and thickened segment of the rachilla. Cryptochloa. Spikelets perfect, or if unisexual, the plants dioecious (except Catheste- cum). Spikelets sessile on opposite sides of a continuous or disarticulating rachis. Spikelets placed edgewise to the rachis; first glume wanting. Lolium. Spikelets placed flatwise to the rachis; both glumes present. Triticum. Spikelets sessile or short-pedicellate on one side of a continuous rachis. Plants monoecious, the florets unisexual (rarely perfect). Cathestecum. Plants with perfect flowers. Spikelets 1-flowered, with no rudimentary florets above the fertile one. Spikes solitary Microchloa. Spikes digitate Cynodon. Spikes racemose Spartina. Spikelets 2-several-flowered or, if only 1-flowered, with one or more rudimentary florets above the perfect one. Spikes digitate. Lemmas awnless, or awn pointed. Rachis prolonged beyond the spikelets in a naked point. Dactyloctenium. Rachis not prolonged Eleusine. Lemmas awned Chloris. Spikes solitary or racemose. Spikes solitary Tripogon. Spikes several to many, racemose. Lemmas entire or minutely bifid, awnless or 1-awned. Rudiment 1-awned, sometimes reduced to one or two awns, rarely wanting. Glumes exceeding the florets, both 1-nerved. Gymnopogon. Glumes shorter than the florets, the first 1-nerved, the second usually 3-5-nerved Gouinia. Rudiment awnless; rachilla and callus of the florets glabrous or nearly so Leptochloa. FIELDIANA: BOTANY, VOLUME 24 Lemmas variously lobed or dentate, usually 3-awned. Spikelets with one perfect floret and one or two rudi- mentary florets above it; rachis not prolonged be- yond the spikelets (except as a single naked point in B. glandulosa) Bouteloua. Spikelets with two perfect florets ; rachis prolonged beyond the spikelets as two inconspicuous hairy bristles. Pentarrhaphis. Spikelets pedicellate in open or contracted panicles (sessile in loose spikes in Jouvea). Spikelets 3-flowered, the lower two staminate, falling attached to the fertile lemma, no rudimentary florets above .... Hierochloe. Spikelets 2-several-flowered, the rachilla usually disarticulating between the similar florets, the lower ones sometimes empty. Lemmas awnless, or awned from the tip, sometimes from between the teeth of a minutely bifid apex. Lemma or rachilla villous with long silky hairs (staminate spikelets glabrous in Gynerium) ; tall stout reeds. Lemma hairy, rachilla glabrous; plants dioecious. .Gynerium. Lemma naked, rachilla hairy; plants with perfect flowers. Phragmites. Lemma and rachilla glabrous or pubescent but not with long silky hairs. Plants dioecious; culms erect from creeping rhizomes. Staminate and pistillate spikelets similar in appearance. Distichlis. Staminate and pistillate spikelets very unlike, the stami- nate many-flowered, rather distant in a loose spike, the pistillate solitary or clustered, nearly hidden in the leaves Jouvea. Plants with perfect flowers. Blades ovate to lanceolate, with conspicuous transverse veins, most of them distinctly petiolate. Glumes narrow, acute, without transverse veins; pan- icles usually large, the spikelets borne only at the ends of the fragile filiform branchlets. . . .Orthoclada. Glumes broad with prominent transverse veins, the sum- mit irregularly toothed Zeugites. Blades linear, with no transverse veins. Lemmas 3-nerved Eragrostis. Lemmas 5- to several-nerved, the nerves sometimes obscure. Spikelets with 1-4 empty lemmas below the fertile florets, large and very flat Uniola. SWALLEN: GRASSES OF GUATEMALA 7 Spikelets with no empty lemmas below the fertile florets. Spikelets short-pedicellate, rather distant in a simple raceme Br achy podium. Spikelets in open or contracted panicles. Lemmas awned from between the teeth of the minutely bifid apex, conspicuously com- pressed Bromus. Lemmas awnless or awned from the tip, rounded or obscurely keeled. Lemmas acuminate or awned Festuca. Lemmas awnless, obtuse or acute. Spikelets inflated; palea much shorter and smaller than the lemma Briza. Spikelets not inflated; palea as long as the lemma. Lemmas prominently 7-nerved, the nerves parallel Glyceria. Lemmas 5-nerved, the nerves inconspic- uous; keel and margins of lemma often pubescent Poa. Lemmas awned from the back; glumes as long as the lowest floret, usually about as long as the spikelet. Plants annual; spikelets large in open panicles Avena. Plants perennial; spikelets small in rather dense or spikelike panicles Trisetum. Spikelets 1-flowered. Spikelets strongly laterally compressed; glumes minute or want- ing; articulation below the spikelet. Glumes minute; lemmas often awned Oryza. Glumes wanting; lemmas awnless Leersia. Spikelets terete, or at least not strongly compressed; glumes usually well developed; articulation above the glumes (below the glumes in Cinna and Polypogon). Glumes awned Polypogon. Glumes awnless, or, if awned, much shorter than the floret. Lemma with a very short awn from just below the apex. Cinna. Lemma awnless or with a well-developed awn. Fertile spikelets surrounded by numerous sterile spikelets in the form of bristles or delicate bracts. . . .Pereilema. Spikelets all perfect, not surrounded by bristles. Lemma indurate; callus bearded, usually sharp-pointed. Awn trifid, the lateral ones sometimes reduced or wanting Aristida. FIELDIANA: BOTANY, VOLUME 24 Awn simple, geniculate, twisted. Glumes much shorter than the floret; awn inserted from the back of the lemma Triniochloa. Glumes as long as or longer than the floret; awn terminal. Margins of lemma overlapping, enclosing the palea; callus narrow, acuminate, sharp- pointed Stipa. Margins of lemma not meeting, exposing the sul- cus of the palea, this projecting from the summit as a minute point; callus short, acute Piptochaetium. Lemma not indurate; callus glabrous or, in Calamagrostis, bearded. Glumes longer than the floret, equal. Callus bearded ; palea usually as long as the lemma. Calamagrostis. Callus glabrous or nearly so; palea usually much shorter than the lemma, thin Agrostis. Glumes, or at least one of them, shorter than the floret. Lemma 3-nerved, acute, awned or awnless. Muhlenbergia. Lemma 1-nerved, obtuse, awnless Sporobolus. Spikelets with 1 perfect terminal floret and a sterile or staminate floret below it (both florets usually fertile in Isachne); articulation below the glumes (except in Arundinella), either in the pedicel, the rachis, or at the base of a cluster of spikelets. Glumes membranaceous; fertile lemma indurate or at least as firm as the glumes; sterile lemma like the glumes in texture. Fertile lemma scarcely firmer than the glumes, awned, the awns relatively long, geniculate. Spikelets large, in groups of three at the ends of the branches. Tristachya. Spikelets small, evenly distributed in the panicle Arundinella. Fertile lemma usually much firmer than the glumes, awnless or awn-tipped. Spikelets subtended by bristles or enclosed in spiny burs. Spikelets subtended by bristles. Bristles persistent. Spikelets arranged in one-sided racemes, each subtended by a single bristle; blades not plaited Ixophorus. Spikelets paniculate, the subtending bristles 2 or more, or if only one, the blades plaited Setaria. Bristles deciduous, falling with the spikelet Pennisetum. Spikelets enclosed in spiny burs Cenchrus. SWALLEN: GRASSES OF GUATEMALA 9 Spikelets neither subtended by bristles nor enclosed in spiny burs. Spikelets arranged on one side of spikelike racemes. Margins of fertile lemma thin, not inrolled. Spikelets densely covered with long tawny silky hairs . . Trichachne. Spikelets glabrous or pubescent but not long-silky Digitaria. Margins of fertile lemma inrolled, indurate. Rachilla joint and first glume adnate, forming a swollen ring-like callus Eriochloa. Rachilla joint and first glume neither adnate nor swollen. Racemes solitary (see also Paspalum). Spikelets sunken in a thick corky rachis; rachis disarticulating at maturity Stenotaphrum. Spikelets not sunken in a thick corky rachis; rachis not dis- articulating at maturity. Spikelets conspicuously tuberculate-hispid; first glume acu- minate, longer than the sterile lemma; raceme stout, stiffly spreading Echinolaena. Spikelets glabrous or hairy but not conspicuously tuber- culate-hispid. Rachis rather broadly winged, partially enfolding the spikelets; spikelets paired but rather distant, appear- ing as if solitary in a single row, the spikelets of each pair placed back to back Thrasya. Rachis wingless; spikelets solitary, the back of the fertile lemma turned from the rachis Mesosetum. Racemes 2 to many (sometimes solitary in Paspalum). Spikelets awned or awn-pointed. Base of spikelet elongate, forming a sharp-pointed bearded callus; both glumes long-awned Chaetium. Base of spikelet blunt, not bearded. First glume long-awned, the body nearly as long as the spikelet; spikelets glabrous or pubescent but not hispid Oplismenus. First glume awnless, less than half as long as the spikelet; spikelets hispid Echinochloa. Spikelets awnless. Fertile lemma with small wings at the base, these some- times reduced to scars Ichnanthus. Fertile lemma wingless. First and second glume equal, nearly as long as the spikelet, the second becoming spiny at maturity; racemes loosely flowered Pseudechinolaena. First glume not more than half as long as the spikelet, or wanting, the second as long as the spikelet, glabrous or pubescent but not spiny. 10 FIELDIANA: BOTANY, VOLUME 24 Back of the fruit turned away from the rachis. First glume well developed Brachiaria. First glume wanting Axonopus. Back of the fruit turned toward the rachis. First glume always present Panicum. First glume usually wanting (often present in P. langei and occasionally in other species). Paspalum. Spikelets paniculate (panicles dense and spikelike in Sacciolepis and Hymenachne amplexicaulis) . Spikelets villous with appressed or spreading hairs. First glume present; spikelets with rose-colored, silky hairs ob- scuring the spikelet Rhynchelytrum. First glume wanting; spikelets with pale hairs, not obscuring the spikelet Leptocoryphium. Spikelets glabrous or pubescent. Fertile lemma with small wings at the base, these sometimes reduced to scars Ichnanthus. Fertile lemma wingless. Spikelets with 2 fertile florets Isachne. Spikelets with only 1 fertile floret. Second glume inflated, saccate at the base; spikelets un- symmetrical Sacciolepis. Second glume not inflated; spikelets symmetrical. First and second glume equal, similar, as long as the spike- let; plants widely decumbent-spreading. . .Homolepis. First glume rarely more than half as long as the second, the latter usually equalling or exceeding the fruit. Panicles dense, spikelike or with narrowly ascending branches; fruit scarcely indurate, open at summit. Hymenachne. Panicles mostly open, loosely flowered; fruit indurate, closed at summit, the lemma tightly enclosing the palea. Spikelets with a tuft of woolly hairs at the tip of the second glume and sterile lemma; plants woody, clambering Lasiacis. Spikelets without woolly hairs; plants herbaceous. Panicum. Glumes indurate; fertile lemma hyaline or membranaceous, the sterile lemma like the fertile one in texture; spikelets arranged in pairs in narrow spikes or racemes. Spikelets with perfect flowers, each perfect spikelet usually paired with a staminate or reduced sterile spikelet, or sometimes all the spikelets perfect and alike. Blades ovate, cordate-clasping; plants creeping; annual Arthraxon. SWALLEN: GRASSES OF GUATEMALA 11 Blades linear; culms erect. Racemes paniculate (see also Andropogon saccharoides) . Panicles conspicuously silky; spikelets awnless. Panicles white or pinkish, loose but rather dense. Rachis continuous; spikelets unequally pedicellate. . .Imperata. Rachis breaking up at maturity; lower spikelet sessile, the upper pedicellate Saccharum. Panicles golden brown, very dense and compact Eriochrysis. Panicles not silky; spikelets awned. Pedicellate spikelet staminate Sorghum. Pedicellate spikelet wanting, only the pedicel present. Sorghastrum. Racemes solitary, paired, or digitate, sometimes aggregate in a large compound inflorescence; if paniculate, the racemes crowded in a dense, silky, terminal panicle. Spikelets all perfect, alike; racemes digitate; spikelets awnless. Ischaemum. Spikelets of each pair unlike, the lower sessile, perfect, the upper pedicellate, usually reduced (conspicuous in Hackelochloa and Diectomisi). Spikelets awnless. Plants annual; rachis joint and the pedicel of the upper spikelet grown together; first glume of sessile spikelet globose, alveolate Hackelochloa. Plants perennial; rachis joint and pedicel distinct. Rachis joints and pedicels much thickened at the summit, glabrous; pedicellate spikelet rudimentary. . .Manisuris. Rachis joints and pedicels not much thickened at the summit; pedicellate spikelet staminate or neuter Elyonurus. Spikelets, at least the fertile ones, awned. Culms simple, usually with a single terminal erect raceme. Glumes of staminate spikelets conspicuous; both spikelets of the lower few to several pairs staminate or neuter, awn- less, the rest of the sessile spikelets perfect, long-awned. Heteropogon. Glumes of staminate spikelets inconspicuous; all pairs of spikelets alike, the sessile bearing a relatively slender plumose awn Trachypogon. Culms branching, at least toward the summit; awns glabrous or scabrous. Pedicellate spikelet conspicuous, the first glume broad, awned, obscuring the spikelets; awn of fertile lemma 4-5 cm. long, geniculate; plants annual Diectomis. Pedicellate spikelet inconspicuous; awn of fertile lemma us- ually less than 15 mm. long; plants perennial. 12 FIELDIANA: BOTANY, VOLUME 24 First glume sharply 2-keeled, at least toward the summit. Spikelets of all pairs unlike, the sessile fertile, the pedi- cellate sterile Andropogon. Spikelets of the lower pairs alike, staminate or neuter. Cymbopogon. First glume of sessile spikelet rounded on the back, the margins involute Hyparrhenia. Spikelets unisexual, the staminate and pistillate spikelets in separate in- florescences or the staminate above and the pistillate below in the same spike. Staminate spikelets in a terminal tassel, the pistillate in the axils of the leaves. Pistillate spikes distinct, the spikelets embedded in the hardened rachis, this disarticulating at maturity Euchlaena. Pistillate spikes grown together forming an ear, the grains at maturity much exceeding the glumes Zea. Staminate spikelets above, the pistillate below in the same spike. Spikes short, the 1- or 2-flowered pistillate portion enclosed in a bead- like sheathing bract Coix. Spikes elongate, many-flowered, the pistillate portion breaking up into joints, not enclosed in a sheathing bract Tripsacum. AEGOPOGON Humb. & Bonpl. Spikelets in groups of 3, the groups pedunculate, spreading, falling entire, arranged alternately on opposite sides of a slender flattened axis, the central spikelet fertile, the lateral ones staminate or neuter; spikelets 2-flowered; glumes equal, 1-nerved, notched at the apex, awned from between the lobes; lemmas 3-nerved, longer than the glumes, the nerves extending into awns. Slender perennials with short, narrow, flat blades and small racemes, the groups of spikelets all turned to one side. Species three, southwestern United States to Bolivia. Lobes of glumes acute or awned, firm, purplish A. cenchroides. Lobes of glumes broad, obtuse, papery A. lenellus. Aegopogon cenchroides Humb. & Bonpl. ex Willd. Sp. PL 4: 899. 1806. A. geminiflorus H.B.K. Nov. Gen. & Sp. 1: 133. pi. 43. 1815. A. guatemalensis Gandog. Bull. Soc. Bot. France 66: 298. 1920. Pajdn del rio (Quezaltenango) . Shady banks, brushy hillsides, open grassy places, and roadsides, 1,350-2,700 meters; Alta Verapaz; Izabal; Guatemala; Sacatepe"quez; Solola; Quezaltenango. Mexico to Bolivia and Brazil. Slender, spreading, perennial; culms 20-50 cm. long, erect, or the longer ones spreading, freely branching; sheaths glabrous, keeled; ligule hyaline, 1-2 mm. long, obtuse; blades 2-6 cm. long, 1-2 mm. wide, flat, acuminate, scabrous; SW ALLEN: GRASSES OF GUATEMALA 13 FIG. 1. Aegopogon lenellus. Plant, X l/i\ group of spikelets, X 5; lateral spikelets and central spikelet, X 10. racemes slender, 2-5 cm. long, usually purple; spikelets about 3 mm. long, the central awn of the first floret about 10 mm. long, the others half as long or less. Aegopogon tenellus (Cav.) Trin. Gram. Unifl. 164. 1824. Lamarckia tenella DC. Cat. Hort. Monsp. 1813. Cynosurus tenellus Cav. ex DC. Cat. Hort. Monsp. 120. 1813. Aegopogon unisetus Roem. & Schult. Syst. Veg. 2: 805. 1817. Figure 1. 14 FIELDIANA: BOTANY, VOLUME 24 Pastures, moist shady banks, and cultivated places, 1,500-2,100 meters; Guatemala; Sacatep^quez; Quezaltenango. Arizona; Mex- ico; El Salvador; Honduras; Costa Rica. Similar to A. cenchroides but differing primarily in the broad obtuse lobes of the glumes. AGROSTIS L. Spikelets 1-flowered, the rachilla disarticulating above the glumes, sometimes prolonged beyond the floret; glumes equal or subequal, longer than the floret, usually acute or acuminate; lemma usually obtuse, thinner than the glumes, awnless, or awned from the back, glabrous or more or less hairy on the callus; palea wanting or nearly equaling the lemma. Slender perennials with flat or involute blades and narrow or open panicles of small spikelets. Species about 125, in temperate and cold regions of both hemi- spheres, and in the tropics at higher altitudes. Palea well developed, as long as the lemma or nearly so. Rachilla prolonged beyond the palea; panicles open, few-flowered. .A. exserta. Rachilla not prolonged; panicles dense, many-flowered A. semiverticillata. Palea minute or wanting. Panicles narrow, dense, the branches floriferous from the base. . . .A. tolucensis. Panicles open, or if narrow, the branches naked toward the base. Lemma awnless. Culms 5-10 cm. high, densely tufted; blades short, firm, arcuate. .A. arcta. Culms more than 20 cm. high; blades lax. Ligule truncate, 0.5-1 mm. long; spikelets 1.6-1.8 mm. long. . .A. vesca. Ligule 3-5 mm. long; spikelets 2-3 mm. long A. perennans. Lemma awned. Culms weak, decumbent-spreading, 50-60 cm. long; spikelets 2 mm. long A. laxissima. Culms erect, not more than 45 cm. high; spikelets 2.3-3 mm. long. Panicles diffuse, the branchlets stiffly divaricate; spikelets 2.3-2.5 mm. long; awn tightly twisted below A. abietorum. Panicles narrow with ascending branches; spikelets 2.5-3 mm. long; awn straight or nearly so A. vinosa. Agrostis abietorum Swallen, Contr. U. S. Nat. Herb. 29: 403. 1950. Known only from the type, Volcan Tajumulco, Dept. San Mar- cos, Steyermark 35652. Perennial; culms tufted, erect, 25-45 cm. high; sheaths a little shorter than the internodes, glabrous; ligule 2-4 mm. long, decurrent; blades 4-7 cm. long, SWALLEN: GRASSES OF GUATEMALA 15 1-1.5 mm. wide, flat or becoming involute, rather firm, scabrous; panicles 7-12 cm. long, diffuse, the branches solitary or in pairs, sparsely scabrous, naked at the base, the branchlets and usually the pedicels stiffly divaricate with a pul- vinus in the axils; spikelets 2.3-2.5 mm. long; glumes acute, equal, or the first a little longer, scabrous on the keel; lemma 2 mm. long, scabrous on the nerves, these slightly excurrent, the awn 3 mm. long, inserted about one-fourth above the base, geniculate, tightly twisted below the bend, the callus sparsely bearded on the sides, the hairs short; anthers 1 mm. long. Related to A. laxissima but differs in the stiff habit, the stiffly divaricate panicle branchlets, the longer lemma and anthers, and the tightly twisted awn. Agrostis arcta Swallen, Contr. U. S. Nat. Herb. 29: 405. 1950. Known only from the type collection, moist roadside at Santa Elena, Dept. Chimaltenango, Skutch 422. Perennial; culms rather densely tufted, erect from a decumbent, rhizome-like base, 5-10 cm. high; sheaths glabrous, somewhat keeled; ligule 1-2 mm. long, decurrent; blades firm, folded or involute, curved, blunt, 2-6 cm. long, smooth below, scabrous above and on the margins; panicles 2-3.5 cm. long, the more or less scabrous branches appressed, naked at the base; spikelets 2.1-2.3 mm. long; glumes equal, acute, rather strongly scabrous on the keel; lemma 1.5-1.7 mm. long, truncate, minutely scabrous in lines, the nerves rather prominent at the summit, awnless or with a very slender short awn from the middle of the back; palea minute; anthers 0.6 mm. long. Agrostis exserta Swallen, Contr. U. S. Nat. Herb. 29: 404. 1950. Alpine areas, 3,400-3,700 meters, Huehuetenango (type from Tojquia, Sierra de los Cuchumatanes, Steyermark 50119). Perennial; culms slender, densely tufted, 10-20 cm. high, erect or ascending, glabrous, without culm nodes; sheaths glabrous, those of the innovations very short, the single culm sheath as much as 5.5 cm. long; ligule 1.5-2 mm. long; blades firm, involute, glabrous, curved, 1-4 cm. long; panicles 1-5 cm. long, few-flowered, purple, the short, smooth branches stiffly ascending, branching above the middle, the branchlets bearing one or two spikelets; spikelets 1.5-1.6 mm. long; glumes equal, somewhat cucullate, subacute, minutely scabrous on the keel; lemma about as long as the glumes, very obtuse, minutely erose, awnless or with a short, straight, slender awn from the middle of the back; palea a little shorter than the lemma; rachilla joint one-third as long as the floret. This species is related to A. bacillata Hack., which differs in having culms with one or two nodes, longer, finer, and softer blades, more slender, flexuous, implicate panicle branches, and a much longer rachilla. Agrostis laxissima Swallen, Contr. U. S. Nat. Herb. 29: 402. 1950. 16 FIELDIANA: BOTANY, VOLUME 24 Damp shady banks, dense Abies-Cupressus forests, and sandy Alnus forests, 2,400-3,200 meters; Totonicapan ; Quezaltenango ; San Marcos (type from along road between San Marcos and Serchil, Standley 85379). Perennial; culms slender, weak, apparently decumbent-spreading, 50-60 cm. long; sheaths about as long as the internodes or a little shorter, glabrous; ligule 3-4 mm. long, decurrent; blades flat, lax, mostly 8-15 cm. long, 1-3 mm. wide, glabrous; panicles 7-8 cm. long, open, relatively few-flowered, the slender, sparsely scabrous branches ascending or spreading, somewhat flexuous, naked in the lower half; spikelets 2 mm. long; glumes equal, acute, scabrous on the keel; lemma 1.5 mm. long, thin, truncate, the nerves minutely excurrent, awned, the awn inserted one-third from the base, 3 mm. long, curved, scarcely twisted below, the callus with short hairs on the sides; palea minute; anthers 0.5 mm. long. A specimen from Volcan Santa Maria, Department of Quezal- tenango (Steyermark 34160), has spikelets 3 mm. long, and is doubt- fully referred to this species. Agrostis perennans (Walt.) Tuckerm. Amer. Jour. Sci. 45: 44. 1843. Cornucopiae perennans Walt. Fl. Carol. 74. 1788. Tricho- dium perennans Ell. Bot. S. C. and Ga. 1: 99. 1816. In swamps, along streams, slopes, fields, and pastures, 1,300- 3,700 meters; Alta Verapaz; Huehuetenango. Eastern United States and eastern Mexico. Perennial; culms erect or ascending from a very slender base, as much as 1 meter high; sheaths smooth, mostly shorter than the internodes; ligule 3-5 mm. long; blades soft, lax, the lowermost often filiform, those of the culm 5-15 cm. long, 1-3 mm. wide; panicles 10-30 cm. long, the slender branches in rather distant whorls, naked below, the lower whorls with short branches intermixed; spikelets 2-3 mm. long, the glumes acuminate, scabrous on the keel; lemma 1.5-2 mm. long, awnless palea minute or wanting. Agrostis semiverticillata (Forsk.) C. Christ. Dansk. Bot. Arkiv. 4, pt. 3: 12. 1922. Phalaris semiverticillata Forsk. Fl. Aegypt. Arab. 17. 1775. Agrostis verticillata Vill. Prosp. PI. Dauph. 16. 1779. A. alba var. verticillata Pers. Syn. PI. 1: 76. 1805. Wet ground along streams and ditches, 1,250-1,800 meters; Sacatepe"quez ; Chimaltenango; Quezaltenango. Western United States to Argentina; introduced from the Eastern Hemisphere. Culms erect to widely decumbent-spreading and rooting at the nodes, 15-50 cm. long or sometimes longer; sheaths shorter than the internodes, glabrous; blades mostly 4-12 cm. long, 3-6 mm. wide, firm, scabrous; panicles 3-10 cm. long, densely flowered, lobed, the branches bearing spikelets to the base; spikelets 2 mm. long, usually falling entire, the glumes equal, subobtuse, very scabrous; lemma 1 mm. long, truncate, awnless; palea nearly as long as the lemma, awnless. SW ALLEN: GRASSES OF GUATEMALA 17 Agrostis tolucensis H.B.K. Nov. Gen. & Sp. 1: 135. 1815. Rocky slopes, summits, and volcano craters, 3,000-4,400 meters; Chimaltenango; Solola; Huehuetenango; Quezaltenango; San Mar- cos. Southern Mexico to Chile. Perennial; culms densely tufted, erect, 10-30 cm. or sometimes as much as 50 cm. high; blades soft to rather firm, loosely involute or the culm blades flat, usually less than 1 mm. wide; ligule 1-3 mm. long, decurrent; panicles 3-10 cm. long, narrow, rather dense, the branches appressed, most of them floriferous to the base; spikelets about 3 mm. long, the glumes subequal, acuminate, scabrous on the keel; lemma about 2 mm. long, minutely dentate, awned from near the base, about as long as the glumes, somewhat bent; palea wanting. Agrostis vesca Swallen, Contr. U. S. Nat. Herb. 29: 406. 1950. Moist roadsides and clay slopes, 2,400-4,600 meters; San Mar- cos; Chimaltenango (type from Santa Elena, Skutch 420). Perennial; culms very slender, erect from a decumbent base, 20-30 cm. high; sheaths about as long as the internodes, glabrous; ligule truncate, erose, 0.5-1 mm. long; culm blades mostly 5-9 cm. long, about 1 mm. wide, flat, smooth below, scaberulous above, those of the innovations involute, filiform, sometimes elon- gate; panicle 4-8 cm. long, purple, the slender nearly glabrous branches ascending, branching above the middle, the branchlets few-flowered; spikelets 1.6-1.8 mm. long; glumes equal or nearly so, rather broadly acute; lemma 1.3-1.4 mm. long, truncate, minutely erose, awnless; palea minute; anthers 0.8 mm. long. Agrostis vinosa Swallen, Contr. U. S. Nat. Herb. 29: 402. 1950. Alpine meadows and p'me-Juniperus woodland, 3,100-3,750 meters; Huehuetenango (type from Che"mal, Steyermark 50290). Perennial; culms tufted, erect, 9-26 cm. high, with only one node evident above the base; leaves mostly crowded at the base, the blades firm, stiff, mostly arcuate, 1-4 cm. long, involute, scabrous; ligule 1-2 mm. long, decurrent; panicles 3-10 cm. long, dark purple, the slender scabrous branches appressed, in fascicles of 2-4, rarely with short branches intermixed, usually spikelet-bearing well above the middle, the lower ones as much as 4 cm. long; spikelets 2.5-3 mm. long; glumes unequal, acute or acuminate, scabrous on the keel; lemma 1.6-1.8 mm. long, truncate, awned, the awn inserted one-fourth above the base, about 2 mm. long, scabrous, straight or nearly so, the callus bearded on the sides with short hairs; palea wanting; anthers 1.2-1.3 mm. long. ANDROPOGON L. Spikelets arranged in pairs at each node of a disarticulating rachis, one sessile and perfect, the other pedicellate and staminate or neuter, often very much reduced, the rachis and sterile pedicels sparsely to usually densely ciliate or villous; glumes of sessile spikelet indurate, the first flat, sulcate, or rounded on the back, several-nerved, the median nerve obscure or wanting, the margins keeled 18 FIELDIANA: BOTANY, VOLUME 24 toward the summit; sterile lemma hyaline; fertile lemma hyaline, narrow, shorter than the glumes, awnless or usually awned from the apex or from between lobes, the awn straight, or geniculate and twisted below; pedicellate spikelet as large as the sessile, or more or less reduced, sometimes only the pedicel present, the glumes not indurate. Annuals or usually coarse perennials with solid culms, the spikelets arranged in racemes, these sessile and crowded on a common axis, paniculate, or usually solitary or paired, sometimes in 3's or 5's, the common peduncle enclosed or exserted from a spathe-like sheath, these sheaths often aggregate in a loose or dense, often silky, compound inflorescence. The genus, in the broad sense, comprises nearly 200 species, in warm-temperate and tropical regions of both hemispheres. Racemes solitary on each peduncle. Plants annual. Culms very slender, widely spreading, freely branching A. brevifolius. Culms erect or nearly so, relatively coarse, the branches short, appressed. Blades pilose on the upper surface toward the base; rachis joints and sterile pedicels glabrous above, villous below, the hairs not obscuring the spikelets A. semitectus. Blades not pilose; rachis joints and sterile pedicels densely villous through- out, the hairs obscuring the spikelets A. malacostachyus. Plants perennial. Spikelets awnless; inflorescence dense. Racemes 1 cm. long, nearly glabrous A. virgatus. Racemes 2-3 cm. long, densely hairy A. bicornis. Spikelets awned; inflorescence loose, the racemes usually scattered. Racemes very flexuous, conspicuously villous A. microstachyus. Racemes straight, not conspicuously villous, the spikelets appressed. First glume of sessile spikelet usually densely villous A. hirtiflorus. First glume of sessile spikelet glabrous. Sessile spikelet 5 mm. long; blades 2-5 mm. wide A. semiberbis. Sessile spikelet 4 mm. long; blades usually not more than 1.5 mm. wide A. tener, Racemes two or more. Racemes numerous, sessile, crowded along a common axis in a dense, white or silvery inflorescence. Sessile spikelet 5 mm. long, pitted above the middle A. altus. Sessile spikelet 4 mm. long, not pitted A. saccharoides. Racemes few to several, paniculate, the panicles terminal on the main culm and short branches. Culms decumbent or straggling, rooting at the nodes; panicle branches flexuous, pilose in the axils A. condylotrichus. Culms erect; panicle branches straight, glabrous in the axils. .A. hypogynus. SWALLEN: GRASSES OF GUATEMALA 19 Racemes 2-5, sessile, paired, or digitate. Spikelets awnless. Ligule 2 mm. long; tips of blades acute, not boat-shaped; spikelets 3 mm. long A. leucostachyus, Ligule less than 1 mm. long; tips of blades boat-shaped; spikelets about 4 mm. long A. selloanus. Spikelets awned. Spikelets of the lower pair alike; second glume with a slender divergent awn A. angustattis. Spikelets of the lower pair unlike; second glume awnless. Pedicellate spikelet as long as the sessile, staminate A. gerardi. Pedicellate spikelet greatly reduced, neuter. Racemes aggregate in a dense inflorescence, the ultimate branchlets densely villous below the spathes. Spathes broad, conspicuous; some of the peduncles of the terminal inflorescences elongate A. elliottti. Spathes narrow, inconspicuous; inflorescence plume-like. A. glomeratus. Racemes scattered in a long, loose inflorescence, the ultimate branch- lets glabrous or nearly so below the spathes A. virginicus. Andropogon altus Hitchc. Contr. U. S. Nat. Herb. 17: 208. 1913. Open places, up to 1,500 meters; Huehuetenango; Chiquimula; Guatemala. Mexico; El Salvador; Bolivia; Argentina. Perennial; culms in small clumps, 1-1.5 meters high, erect or ascending at the base, smooth, the nodes bearded with stiff ascending hairs, these usually rather short; sheaths longer or shorter than the internodes, glabrous; ligule membrana- ceous, 3-4 mm. long; blades 15-30 cm. long, 5-10 mm. wide, acuminate, scabrous, with a few long hairs on the upper surface near the base; panicles 15-20 cm. long, dense, the racemes narrowly ascending or appressed, the rachis joints and sterile pedicels densely villous with white hairs 5-8 mm. long; sessile spikelet 5 mm. long, bearded at the base, scabrous on the keels toward the summit, the first glume pitted above the middle; awn 1.5-2 cm. long, geniculate, tightly twisted below the bend, loosely twisted above; pedicellate spikelet reduced, 3-4 mm. long, awnless. Andropogon angustatus (Presl) Steud. Syn. PI. Glum. 1: 370. 1854. Diectomis laxa Nees, Agrost. Bras. 340. 1829. Not Andropogon laxus Willd. 1806. Diectomis angustata Presl, Rel. Haenk. 1: 333. 1830. Andropogon apricus Trin. Me"m. Acad. St. Pe"tersb. VI. Sci. Nat. 2 (1):83. 1836. Brushy or rocky slopes and pine-clad hills; Jalapa; Jutiapa; Santa Rosa. Cuba; southern Mexico; Nicaragua; Panama to Colombia and northern Brazil. 20 FIELDIANA: BOTANY, VOLUME 24 Slender, erect perennial; culms 50-120 cm. high, glabrous; sheaths much shorter to longer than the internodes, compressed, keeled, auriculate, glabrous; ligule firm, 1-2 mm. long, fused with the auriculate summit of the sheath; blades linear, attenuate, 2-3 mm. wide, glabrous beneath, scabrous above and on the margins; flowering branches few to several from the upper sheaths, forming a loose inflorescence; racemes paired, rarely solitary, about 3 cm. long, at first partly included, finally exserted on long, slender, somewhat flexuous peduncles 5-10 cm. long; rachis joints and sterile pedicels thickened above, stiffly ciliate with white hairs; sessile spikelet 6 mm. long, the callus densely bearded with white hairs; first glume narrow, obtuse, deeply sulcate, glabrous; second glume compressed, keeled, with a slender divergent awn about 1 cm. long; awn of fertile lemma 3-4 cm. long, rather stout, brown, hispidulous, 2-geniculate, the lower segments tightly twisted, the upper straight; pedicellate spikelet 5 mm. long, the first glume not sulcate, long hairy on the margins, with a straight slender awn 2-6 mm. long. Andropogon bicornis L. Sp. PI. 1046. 1753. Navajuela (Izabal). Savannas, open or brushy slopes, and pine uplands, up to 1,500 meters; Pete*n; Alta Verapaz; Izabal; Huehuetenango; Solola; Santa Rosa; Guatemala; Suchitepe"quez; Retalhuleu. British Honduras; southern Mexico and the West Indies to Bolivia and Argentina. Coarse perennial; culms 1-2.5 meters high, erect, in rather large clumps, glabrous; sheaths usually shorter than the internodes or the lower ones overlapping, broad, loose, keeled toward the summit, glabrous; ligule 1-1.5 mm. long, minutely erose-ciliate; blades elongate, 2-5 mm. wide, the lower surface glabrous on the midnerve, scabrous, the upper pubescent, the margins very scabrous, especially near the tip; flowering branches numerous from the upper sheaths, very compound, forming a very dense, corymbose feathery inflorescence; racemes paired, 2-3 cm. long, partly enclosed or exserted on long slender peduncles from the narrow inconspicuous spathes, the rachis and sterile pedicels densely hairy, the hairs spreading, as much as 5 mm. long; sessile spikelet 3 mm. long, awnless, glabrous; pedicellate spikelet rudimentary, or occasionally larger than the sessile one. Andropogon brevifolius Swartz, Prodr. Veg. Ind. Occ. 26. 1788. A. obtusifolius Poir. in Lam. Encycl. Suppl. 1: 583. 1810. Pollinia brevifolia Spreng. PI. Pugill. 2: 13. 1815. Schizachyrium brevifolium Nees ex Kunth, Enum. PI. 1: 488. 1833. Sorghum brevi- folium Kuntze, Rev. Gen. PI. 2: 791. 1891. Dry hills and rocky slopes, up to 2,500 meters; Sacatepe"quez ; Guatemala; Escuintla. British Honduras (El Cayo District); tropi- cal regions of both hemispheres. Slender annual; culms 15 cm. to nearly 1 meter long, forming loose tangles or dense mats, ascending from a decumbent base or trailing, freely branching, glabrous; sheaths usually much shorter than the internodes, compressed, keeled, glabrous; ligule membranaceous, about 0.5 mm. long; blades oblong, obtuse, navicular, 1-4 cm. long, 1-5 mm. wide, glabrous, the margins scaberulous, minutely SW ALLEN: GRASSES OF GUATEMALA 21 ciliate at the base; flowering branches slender, numerous, from the middle and upper nodes; racemes solitary, delicate, 1-2 cm. long, partly included in the spathe, the rachis and sterile pedicel glabrous; sessile spikelet 2.5-3 mm. long, the callus bearded, otherwise glabrous, the slender awn about 8 mm. long, genicu- late, tightly twisted below the bend; pedicellate spikelet reduced to a minute slender-awned rudiment. Andropogon condylotrichus Hochst. ex Steud. Syn. PL Glum. 1: 377. 1854. A. piptatherus Hack, in Mart. Fl. Bras. 2 (3): 293. 1883. Amphilophis piptatherus Nash, N. Amer. Fl. 17: 127. 1912. Euclasta condylotricha Stapf in Prain, Fl. Trop. Afr. 9: 181. 1917. Grassy plains and brushy slopes, 400-900 meters; Chiquimula. Mexico and the West Indies to Colombia, Venezuela, and northern Brazil. Annual; culms commonly 1-2 meters long, decumbent or straggling, rooting at the nodes, sending up numerous weak branches, the nodes densely bearded, otherwise glabrous; sheaths usually shorter than the internodes, keeled toward the summit, glabrous on the back, villous in the throat and on the collar; ligule 1 mm. long, membranaceous, with a line of stiff hairs behind it; blades 15-20 cm. long, 4-8 mm. wide, flat, acuminate, sparsely papillose, the margins scabrous; racemes 2-5 cm. long, paniculate, the panicles terminal on the main culm and short branches from the upper sheaths, the panicle branches flexuous, densely villous in the axils; lower pairs of spikelets homogamous; fertile sessile spikelets 4 mm. long, the first glume densely villous, the awn 3-4 cm. long, 2-geniculate, the lower segments brown, tightly twisted, hispidulous, the terminal segment loosely twisted, scabrous; pedicellate spikelets 5-6 mm. long, sparsely papillose- pilose, the keels scabrous. Andropogon elliottii Chapm. Fl. South. U. S. 581. 1860. A. clandestinus Wood, Class-book ed. 3: 809. 1861. Not A. clandes- tinus Nees, 1854. Sorghum elliottii Kuntze, Rev. Gen. PL 2: 791. 1891. Sandy pine uplands, British Honduras (El Cayo District, Lundell 6727, 6785). Eastern United States; Cuba. Perennial; culms slender to rather coarse, as much as 80 cm. high, rather sparingly branching from the upper nodes, densely bearded below the ultimate spathes; sheaths keeled, sparsely pilose, the lower ones broad, the upper ones becoming dilated and conspicuous; blades 3-4 mm. wide, usually pilose with long hairs on the upper surface toward the base; racemes usually in pairs, sometimes 3 or 4, partly included in the spathe or exserted on a long slender peduncle; racemes 3-5 cm. long, flexuous, the rachis and pedicels conspicuously villous; sessile spikelet narrow, 4-5 mm. long, the first glume acute, concave, the fertile lemma bearing a loosely twisted awn 10-15 mm. long; pedicellate spikelet very small or obsolete. Andropogon gerardi Vitm. Summa. PL 6: 16. 1792. A.furcatus Muhl. in Willd. Sp. PL 4: 919. 1806. 22 FIELDIANA: BOTANY, VOLUME 24 Pine forests and limestone hills; Huehuetenango; Jalapa. United States; Mexico; Honduras. Slender or coarse perennial; culms tufted, erect, as much as 2 meters high, simple or sparingly branching from the upper nodes; sheaths keeled or the upper ones rounded on the back, glabrous, or the lower ones sometimes pilose; blades elongate, commonly 3-5 mm. or as much as 10 mm. wide, often sparsely pilose toward the base, the margins very scabrous; racemes 2-6, sometimes solitary on the branches, straight, usually purple, the rachis joints and pedicels densely ciliate; sessile spikelet 7-10 mm. long, the first glume acuminate, sulcate, scabrous toward the tip, the awn 1-2 cm. long, geniculate, twisted below; pedicellate spikelet as long as the sessile but narrower, staminate, awnless. Andropogon glomeratus (Walt.) B.S.P. Prel. Cat. N. Y. 67. 1888. Cinna glomerata Walt. Fl. Carol. 59. 1788. Andropogon mac- rourus Michx. Fl. Bor. Amer. 1: 56. 1803. Sorghum glomeratum Kuntze, Rev. Gen. PI. 2: 790. 1891. Andropogon virginicus var. corymbosus Beal, Grasses N. Amer. 2: 52. 1896. A. corymbosus Nash in Britton, Man. 69. 1901. Marshes, brushy banks, rocky places and open plains; Pete"n; Alta Verapaz; Izabal; Huehuetenango; Sacatepe"quez; Solola; Guatemala. Southeastern United States and the West Indies to Panama. Similar in habit and aspect to A. bicornis; sheaths sometimes appressed- hirsute on the margins and toward the summit; ultimate branchlets densely hairy below the spathes; sessile spikelet 3-4 mm. long, awned, the awn slender, straight, about 1.5 cm. long; pedicellate spikelet very greatly reduced or usually wanting, the pedicel only present. Andropogon hirtiflorus (Nees) Kunth, Rev. Gram. 1: Suppl. 39. 1830. Streptachne domingensis Spreng. ex Schult. Mant. 2: 188. 1824. Not Andropogon domingensis Steud., 1821. Schizachyrium hirtiflorum Nees, Agrost. Bras. 334. 1829. Sorghum hirtiflorum Kuntze, Rev. Gen. PI. 2: 792. 1891. Schizachyrium oligostachyum Nash in Small, Fl. Southeast. U. S. 59. 1903. Andropogon domin- gensis F. T. Hubb. Proc. Amer. Acad. Sci. 49: 493. 1913. Pajdn bianco (Huehuetenango). Open or brushy slopes, pine and pine-oak forests, and meadows, 1,500-2,500 meters; Zacapa; Huehuetenango; Jalapa; Sacatepe"quez ; Solola; Guatemala. Southern United States and the West Indies to Bolivia and Uruguay. Perennial; culms tufted, erect, 0.4-1.5 meters, commonly about 1 meter high, glabrous; sheaths shorter than the internodes, or the lower ones overlapping, gla- brous, keeled, at least toward the summit; ligule 1-1.5 mm. long, brownish; blades 10-20 cm. long, 2-4 mm. wide, or on robust plants as much as 30 cm. long and 8 SW ALLEN: GRASSES OF GUATEMALA 23 mm. wide, scaberulous, the margins scabrous; racemes mostly 4-8 cm. long, few to numerous, scattered on the flowering branches from the upper nodes, forming a loose inflorescence; rachis joints and pedicels densely villous all over or only on the sides; sessile spikelets 5-6 mm. long, sparsely to densely villous, the middle of the back sometimes glabrous, the awn about 1 cm. long, geniculate, tightly twisted below the bend, loosely twisted above; pedicellate spikelet reduced to a small short-awned rudiment. An extremely variable species in size, habit, and pubescence of the racemes. Andropogon hypogynus Hack, in Mart. Fl. Bras. 2 (3): 290. pi. 66. 1883. Hypogynium campestre Nees, Agrost. Bras. 365. 1829. Not Andropogon campestris Kunth, 1830, nor Trin., 1832. A. hypogynus genuinus Hack, in Mart. Fl. Bras. 2 (3) : 290. pi. 66. 1883. A. hypogynus anatherus Hack, in Mart. Fl. Bras. 2 (3) : 290. pi. 66. 1883. Open grassy plains; Izabal. Colombia; Brazil; Paraguay; nor- thern Argentina. Perennial; culms rather coarse, erect, 1-2 meters high; sheaths compressed, keeled, glabrous, the upper ones much shorter than the internodes; blades flat, 15-40 cm. long, 3-5 mm. wide, glabrous; racemes several, nearly straight, fascicled on a short axis, unequal, as much as 6 cm. long, the rachis joints and pedicels ciliate, the hairs inconspicuous; sessile spikelet 4 mm. long, bearded at the base, the first glume acute, somewhat concave, glabrous, the fertile lemma awnless or with a rather short straight awn; pedicellate spikelet larger than the sessile one, staminate, awnless, the first glume acuminate, rather strongly nerved. Andropogon leucostachyus H.B.K. Nov. Gen. & Sp. 1: 187. 1816. A. lanuginosus H.B.K. Nov. Gen. & Sp. 1: 187. 1816. Cola de venado (Izabal). Open fields, plains, banks, and pine ridges at low altitudes; Pete*n; Alta Verapaz; Izabal. British Honduras; southern Mexico and the West Indies to Argentina. Slender perennial; culms in small dense tufts, erect, 25-70 cm. high, glabrous; sheaths narrow, compressed, glabrous, the lower ones crowded; ligule 1-1.5 mm. long, thin, truncate, minutely erose; blades 5-15 cm. long, or those on the innova- tions as much as 35 cm. long, 1-3 mm. wide, acute, scaberulous; flowering branches few, long and slender, sparingly branched; racemes paired, sometimes 3, exserted on long slender peduncles, the spathes rather long, but very narrow and incon- spicuous; rachis and sterile pedicels slender but straight, densely villous, the spreading hairs commonly 10 mm. long; sessile spikelet 3 mm. long, glabrous, awnless; pedicellate spikelet wanting. Andropogon malacostachyus Presl, Rel. Haenk. 1: 337. 1830. Schizachyrium malacostachyum Nash, N. Amer. Fl. 17: 102. 1912. 24 FIELDIANA: BOTANY, VOLUME 24 Rocky hills, 600-1,500 meters; Alta Verapaz; Guatemala. Mex- ico (Guerrero, type). Annual; culms 8-35 cm. high, erect or geniculate at the lower nodes, scabrous, or strigose below the nodes, with short flowering branches from the upper nodes, sometimes from all the nodes; sheaths usually much shorter than the internodes, these sometimes elongate; ligule membranaceous, minutely ciliate, about 1 mm. long; blades 2-5 cm. long, 2-3 mm. wide, flat or usually folded, very scabrous on the margins; racemes solitary on the short branches, mostly shorter than the spathes, these becoming flat and rather conspicuous; rachis joints thickened upward, lunar in cross section, densely villous across the back, the sterile pedicel similar but narrower; sessile spikelet 7-8 mm. long, acuminate, minutely toothed, densely villous over the back, the callus densely bearded; fertile lemma awned from near the base, the awn about 1.5 cm. long, geniculate, tightly twisted below the bend, loosely twisted above; pedicellate spikelet narrow, 3 mm. long, with a straight awn about 5 mm. long. Andropogon microstachyus Desv. ex Hamilt. Prodr. PL Ind. Occ. 8. 1825. Pollinia microstachya Desv. Opusc. 70. 1831. Dry fields, open pine forests, and rocky or brushy slopes, up to 1,600 meters; Pete"n; Alta Verapaz; Huehuetenango; Chiquimula; Sacatepe"quez; Chimaltenango. Southern Mexico and the West Indies to Argentina. Rather coarse perennial; culms 1-1.5 meters high, erect, glabrous; sheaths mostly shorter than the internodes, sometimes overlapping, strongly compressed, keeled, glabrous or scaberulous; ligule firm, truncate, about 2 mm. long; blades 10-20 cm. or even 25 cm. long, 5-10 mm. wide, conduplicate or becoming flat, glabrous, the margins scaberulous; flowering branches numerous from the upper sheaths, ascending or appressed, forming a large, dense, feathery, corymbose, compound inflorescence; racemes solitary, 2-3 cm. long, partly included in the short inconspicuous spathes, the rachis strongly flexuous, the rachis joints and sterile pedicels long- villous on the sides; sessile spikelet 4 mm. long, narrow, acuminate, the callus shortly bearded, the delicate awn 8-12 mm. long, geniculate, tightly twisted below the bend, loosely twisted above; pedicellate spikelet rudi- mentary, awnless or with a short thread-like awn. Andropogon saccharoides Swartz, Prodr. Veg. Ind. Occ. 26. 1788. A. argenteus DC. Cat. Hort. Monsp. 77. 1813. A. laguroides DC. Cat. Hort. Monsp. 78. 1813. A. torreyanus Steud. Norn. Bot. ed. 2. 1: 93. 1840. Sorghum saccharoides Kuntze, Rev. Gen. PI. 2: 792. 1891. Amphilophis saccharoides Nash, N. Amer. Fl. 17: 125. 1912. Bothriochloa saccharoides Rydb. Brittonia 1 : 81. 1931. Figure 2. Prairies, meadows, pine forests, and roadsides, 1,000-1,800 meters; Quiche"; Huehuetenango; Chimaltenango; Santa Rosa; Guatemala. Southwestern United States and the West Indies to Argentina. FIG. 2. Andropogon saccharoides, X 25 26 FIELDI ANA: BOTANY, VOLUME 24 Tufted perennial; culms erect, brittle, 0.5-2 meters high, the nodes usually glabrous but sometimes some of them densely pubescent, but scarcely bearded; sheaths rounded on the back, glabrous; blades flat, acuminate, 10-20 cm. or even 30 cm. long in robust plants, 2-8 mm. wide, scabrous, papillose-hirsute near the base; panicles 5-15 cm. long, dense, white-silky, the usually numerous branches appressed or narrowly ascending; sessile spikelet 4 mm. long, the geniculate twisted awn mostly 1-1.5 cm. long; pedicellate spikelet as long as the sessile, but much narrower, awnless. Andropogon selloanus (Hack.) Hack. Bull. Herb. Boiss. II. 4: 266. 1904. A. leucostachyus selloanus Hack, in DC. Monogr. Phan. 6:420. 1889. Pine woods and margins of swamps to about 1,300 meters; Pete"n; Huehuetenango; Chiquimula. British Honduras; Mexico (Chiapas); the West Indies and Panama to Argentina. Densely tufted perennial resembling A. leucostachyus; culms erect, 45-100 cm. high, solitary or few in each tuft, glabrous; sheaths compressed, keeled, glabrous; ligule 0.5 mm. long; blades conduplicate, becoming flat, 3-5 mm. wide, those of the culm 5-8 cm. long, the uppermost much reduced or wanting, those of the innovations sometimes as much as 20 cm. long; flowering branches long and slender, solitary from the middle and upper sheaths, unbranched; racemes 3-5, exserted from the long and narrow but inconspicuous spathes, densely villous with tawny hairs more than 10 mm. long; sessile spikelet 3-4 mm. long, awnless, glabrous; pedicellate spikelet wanting. Andropogon semiberbis (Nees) Kunth, Rev. Gram. Suppl. 1: 39. 1830. Schizachyrium semiberbe Nees, Agrost. Bras. 336. 1829. Dry or rocky hills and plains; Chiquimula; Jalapa. British Honduras; Florida, eastern Mexico, and the West Indies to Ecuador and Argentina. Very similar to A. hirtiflorus, differing primarily in the glabrous or scabrous first glume of the sessile spikelet, and the glabrous or only sparsely hairy rachis joints and sterile pedicels, the hairs confined to the margins near the summit; culms stouter, on the average, the blades rarely less than 4 mm. wide. Andropogon semitectus Swallen, Contr. U. S. Nat. Herb. 29: 427. 1950. Type from Baiios de Santa Maria, Zacapa, Standley 73919. Mexico (Jalisco; Guerrero). Annual; culms erect, 21-55 cm. high, glabrous, with flowering branches from the middle and upper nodes, all the internodes of about equal length; sheaths about half as long as the internodes, keeled, glabrous; ligule 0.5 mm. long, minutely ciliate; blades mostly 4-9 cm. long, 1.5-3 mm. wide, flat or folded, papillose-pilose on the upper surface toward the base with long hairs, the margins scabrous; spathes 2.5-3.5 cm. long; racemes solitary, mostly included, only the SWALLEN: GRASSES OF GUATEMALA 27 uppermost spikelets exserted from the spathe, the peduncle very short; rachis joints and sterile pedicels broad but rather thin, lunate in cross section, densely villous on the lower part of the back, the upper part glabrous, the rachis joint somewhat widened at the summit with thin, almost wing-like margins, the tip cup-shaped; sessile spikelet 6 mm. long, narrow, the glumes acuminate, the first densely villous in the lower half; lemma 2.5 mm. long, awned, the awn inserted one-third from the base, 14 mm. long, tightly twisted below, geniculate, the twisted part dark brown, 6 mm. long; pedicellate spikelet greatly reduced, sca- brous, bearing a slender straight scabrous awn 3-5 mm. long. Andropogon tener (Nees) Kunth, Rev. Gram. 1: Suppl. 39. 1830. Schizachyrium tenerum Nees, Agrost. Bras. 336. 1829. An- dropogon gracilis Presl, Rel. Haenk. 1: 336. 1830. Not A. gracilis Spreng., 1825. A. preslii Kunth, ReV. Gram. 1: Suppl. 39. 1830. A. kptophyllus Trin. Me"m. Acad. St. Pe"tersb. VI. Math. Phys. Nat. 2: 264. 1832. Sorghum tenerum Kuntze, Rev. Gen. PI. 2: 792. 1891. Along roads; Huehuetenango. British Honduras (El Cayo Dis- trict); southeastern United States; eastern Mexico; the West Indies; Panama to Argentina. Densely tufted perennial; culms usually very slender, erect or reclining, 30-100 cm. long, glabrous; sheaths narrow, keeled, glabrous, the lower longer, the upper shorter than the internodes; ligule about 0.2 mm. long; blades commonly 5-10 cm. long, 1-3 mm. wide, flat or conduplicate, sometimes subinvolute, more or less curved or flexuous, sparsely papillose-hirsute near the base; flowering branches rather few and distant, slender, some of the racemes exserted on long slender peduncles; racemes slender, but straight, 2-5 cm. long, the rachis joints and sterile pedicels with a few long hairs on the sides near the summit, otherwise glabrous; sessile spikelet 5-6 mm. long, acute or acuminate, scabrous at least toward the tip, the callus rather densely bearded, the awn 7-12 mm. long, genicu- late, tightly twisted below the bend ; pedicellate spikelet as large as the sessile one, awnless. Andropogon virgatus Desv. ex Hamilt. Prodr. PI. Ind. Occ. 9. 1825. Hypogynium spathiflorum Nees, Agrost. Bras. 366. 1829. Andropogon spathiflorus Kunth, ReV. Gram. 1: Suppl. 40. 1830. Marshy prairies and stream banks at low altitudes; Izabal. British Honduras (El Cayo District); Costa Rica; the West Indies; Panama to Bolivia and Argentina. Perennial; culms relatively slender, tufted, commonly 1-1.5 meters high, erect, glabrous, usually tinged dull red or brownish; sheaths usually much shorter than the long internodes, compressed, keeled, glabrous; ligule membranaceous, 0.5 mm. long; blades elongate, especially those of the innovations, 2-5 mm. wide, conduplicate, becoming flat, the lower surface glabrous, the upper often more or less villous, the margins obscurely scabrous, sometimes ciliate near the base; inflorescence long and narrow, the slender, relatively short branches closely appressed, bearing numerous solitary racemes 1 cm. long, partly enclosed in small 28 FIELDIANA: BOTANY, VOLUME 24 reddish or purplish spathes; spikelets green, 3 mm. long, awnless, the pedicellate as large as the sessile one; first glume scabrous on the keels. Andropogon virginicus L. Sp. PL 1046. 1753. Cinna lateralis Walt. Fl. Carol. 59. 1788. Andropogon dissitiflorus Michx. Fl. Bor. Amer. 1: 57. 1803. Anatherum virginicum Spreng. PI. Pugill. 2: 16. 1815. Andropogon vaginatus Ell. Bot. S. C. and Ga. 1: 148. 1816. A. tetrastachyus Ell. Bot. S. C. and Ga. 1: 150. pi. 8, f. 4- 1816. A. eriophorus Scheele, Flora 27 : 51. 1844. A. louisianae Steud. Syn. PI. Glum. 383. 1854. A. curtisianus Steud. Syn. PI. Glum. 1: 390. 1854. Sorghum virginicum Kuntze, Rev. Gen. PI. 2: 792. 1891. Figure 3. Pine woods; Jalapa; Quezaltenango; Huehuetenango. British Honduras; southern United States; the West Indies; Mexico (Vera- cruz); Costa Rica; Panama. Densely tufted perennial; culms erect, 1-1.5 meters high, glabrous; lower leaves crowded in a dense basal cluster, the sheaths flattened, keeled, glabrous, or somewhat hirsute at the summit, the blades elongate, 2-4 mm. wide, the upper surface scabrous, more or less villous toward the base; culm sheaths much shorter than the internodes; ligule about 0.5 mm. long, minutely ciliate; flowering branches from the middle and upper nodes forming a loose inflorescence nearly half the length of the culms; racemes paired, slender, flexuous, partly enclosed in the broad conspicuous spathes, the rachis and sterile pedicels villous with long slender white hairs; sessile spikelet 3-4 mm. long, bearing a straight slender awn 10-15 mm. long; first glume acuminate, scabrous on the keels near the summit. ANTHEPHORA Schreb. Spikelets 1-flowered, in groups of 4, the first glumes many-nerved, indurate, thickened and united at the base, forming a false involucre around the spikelets, the groups short-pedicellate, falling entire; second glume 5-nerved, narrowed to a blunt tip; lemma ovate-acuminate, 3-nerved, firm but not indurate, the broad flat margins curved around and enclosing the palea. Weedy annuals, in our species, with flat blades and terminal spikelike racemes. Species five, four in Africa and one in tropical America. Anthephora hermaphrodita (L.) Kuntze, Rev. Gen. PL 2: 759. 1891. Tripsacum hermaphrodita L. Syst. Nat. ed. 10. 2: 1261. 1759. Anthephora elegans Schreb. Beschr. Gras. 2: 105. pi. 44. 1810. A. villosa Spreng. Neu. Entd. 3: 14. 1822. Cenchrus villosus Spreng. Syst. Veg. 1: 301. 1825. Figure 4. Open ground, roadsides, and waste places, sea level to about 2,000 meters; Izabal; Santa Rosa; Escuintla; Guatemala. British Honduras; the West Indies; Mexico to Peru and Brazil. A common weed in tropical America. FIG. 3. Andropogon virginicus. Plant, X Yz', spikelet with rachis joint and pedicel, X 5. 29 30 FIELDIANA: BOTANY, VOLUME 24 FIG. 4. Anthephora hermaphrodite, X Annual; culms erect or decumbent at the base, branching, rooting at the lower nodes, 15-50 cm. high; sheaths glabrous or papillose-hirsute near the summit; ligule 2-3 mm. long, thin, brownish; blades 5-20 cm. long, 3-8 mm. wide, flat, acuminate, scabrous; racemes 5-10 cm. long, erect; first glumes 5-7 mm. long, broad, acute or acuminate, scabrous. SW ALLEN: GRASSES OF GUATEMALA 31 ARISTIDA L. Spikelets 1 -flowered, disarticulating above the glumes; glumes usually unequal, 1-nerved, or rarely 3-5-nerved, acuminate or awned; lemma indurate at maturity, terete, convolute around the palea, glabrous or scabrous toward the tip with a sharp, entire or minutely bifid, bearded callus; awns 3, the lateral sometimes very short or wanting, sometimes united at the base in a slender twisted column. Densely tufted annuals or perennials with involute or narrow flat blades and open or contracted, occasionally spikelike panicles. Species probably about 200, in warmer parts of both hemispheres. Lateral awns wanting or very much reduced. Awn (column) twisted at base A. schiedeana. Awn not twisted. Plants annual; culms freely branching; panicles narrow, the short branches spikelet-bearing to the base; central awn curved or flexuous, the lateral ones wanting A. jorullensis. Plants perennial; culms simple; panicles open, diffuse, the long branches naked below; central awn straight, the lateral ones present but very much reduced A. ternipes. Lateral awns well developed, nearly as long as the central one. Plants annual. Column twisted, as long as the lemma; awns about 5 mm. long. .A. capillacea. Column wanting; awns 10-15 mm. long A. adscensionis. Plants perennial. Panicles open, the branches spreading or drooping, naked below. Summit of lemma with a twisted neck A. laxa. Summit of lemma not twisted. Panicle branches drooping, loosely few-flowered at the ends. A. longifolia. Panicle branches stiffly spreading, rather densely flowered above the middle A. hamulosa. Panicles narrow, usually dense, the branches appressed or narrowly ascend- ing. Lemma narrowed above in a slender twisted column. Column 3-5 cm. long; glumes long-awned A. implexa. Column short, not more than 5 mm. long; glumes awnless. Panicles dense, interrupted; lemma 3.5-4 mm. long, much shorter than the glumes; awns loosely twisted below A. recurvata. Panicles narrow but loose; lemma 8-12 mm. long, about as long as the glumes; awns divergent, not twisted A. orizabensis. Lemma not twisted above, 5-7 mm. long A. purpurascens. Aristida adscensionis L. Sp. PI. 82. 1753. Chaetaria ascensionis Beauv. Ess. Agrost. 30, 151, 158. 1812. Aristida bromoides H.B.K. Nov. Gen. & Sp. 1: 122. 1815. A. coarctata H.B.K. Nov. Gen. & 32 FIELDIANA: BOTANY, VOLUME 24 Sp. 1: 122. 1815. Chaetaria bromoides Roem. & Schult Syst Veg 2: 396. 1817. Figure 5. Fields and dry open ground, up to 1,500 meters; Alta Verapaz; El Progreso; Zacapa; Guatemala. Southwestern United States and FIG. 5. Aristida adscensionis, X 1. the West Indies to Chile and Argentina; warmer parts of the Old World. Annual; culms freely branching, erect or geniculate ascending, glabrous, 0-80 cm. tall; sheaths glabrous; blades as much as 10 cm. long, 2 mm. wide, flat or often short and involute, scabrous above; panicles mostly 5-15 cm. long, dense or often loose and drooping; glumes 1-nerved, the first 5-7 mm. long, obtuse or subacute, the second 8-10 mm. long, acute or blunt; lemma 6-9 mm. long, sca- brous on the keel above, the callus subobtuse, densely short-pilose; awns 10-15 mm. long, subequal, equally divergent, flat at the base, gradually narrowed to a fine point. Aristida capillacea Lam. Tabl. Encycl. 1: 156. 1791. A. elegans Rudge, PI. Guian. 22. pi. 30. 1805. Chaetaria capillacea Beauv. Ess. Agrost. 30, 158. pi. 8, f. 6. 1812. Aristida sanctae-luciae Trin. Gram. Pan. 25. 1826. Chaetaria capillaris Nees, Agrost. Bras. 388. 1829. Pine forests, about 1,500 meters; Chiquimula. British Honduras; southern Mexico; Honduras; Costa Rica; Panama; Colombia to Bolivia and Brazil. SW ALLEN: GRASSES OF GUATEMALA 33 Delicate annual; culms 5-25 cm. high, erect, freely branching; blades 1-5 cm. long, less than 1 mm. wide, scabrous on the margins, often sparsely pilose with long white hairs; panicles 2-8 cm. long, usually tinged with purple, the capillary branches ascending or spreading, more or less flexuous, naked below, not more than 2 cm. long; glumes narrow, acuminate, the first 2-2.5 mm. long, the second 2.5-3 mm. long, sometimes subequal; lemma 2 mm. long, tapering into a slender twisted column 1.5-2 mm. long; awns about 5 mm. long, divergent. Aristida hamulosa Henr. Med. Rijks Herb. Leiden 54: 219. 1926. Dry hills and scrub oak forests, 1,400-1,600 meters; Jalapa; Guatemala. Southwestern United States; Mexico. Perennial; culms rather slender, erect, 40-70 cm. or even as much as 1 meter tall; sheaths glabrous or scaberulous, all longer than the internodes; blades as much as 30 cm. long, less than 3 mm. wide, flat or becoming involute, glabrous beneath, finely scabrous above; panicles commonly 25-40 cm. long, sometimes three-fourths the height of the plant, the branches stiffly spreading, more or less drooping, naked in the lower half, the lower ones as much as 20 cm. long; spikelets appressed; glumes 12-15 mm. long, subequal, acuminate; lemma about 12 mm. long, usually strongly scabrous, not twisted, the central awn 1.5-2.5 cm. long, the lateral ones shorter, somewhat divergent. Aristida implexa Trin. Me"m. Acad. St. P^tersb. VI. Sci. Nat. 2, no. 1:48. 1836. Abundant in sandy pine uplands, San Augustin, Mountain Pine Ridge, El Cayo District, British Honduras, Lundell 6904. El Sal- vador; Brazil. Perennial; culms caespitose, erect, as much as 1 meter high, glabrous; sheaths glabrous, the lower ones crowded ; blades elongate, attenuate, flexuous, flat at the base, 2-3 mm. wide, glabrous beneath, finely scabrous above, the lower ones becoming curled with age; panicles dense, spikelike, 10-25 cm. long, the short branches appressed; glumes subequal, about 1 cm. long, strongly scabrous, awned, the awns 5-10 mm. long; lemma 5-6 mm. long, the twisted neck 3-5 cm. long, the awns divergent, 2-4 cm. long. Aristida j or u lien sis Kunth, Rev. Gram. 1: 62. 1829. Strep- tachne pilosa H.B.K. Nov. Gen. & Sp. 1: 124. 1815. Not Aristida pilosa Labill., 1824. Ortachne pilosa Nees, Seem. Bot. Voy. Herald 225. 1854. Aristida manzanilloana Vasey, Contr. U. S. Nat. Herb. 1:282. 1893. Deserts and rocky slopes at low altitudes; Zacapa; Jutiapa. Mexico to Panama. Erect annual in small tufts; culms 10-45 cm. high, rarely more, slender, freely branching from all the nodes; blades mostly less than 10 cm. long, 1-2 mm. wide, 34 FIELDIANA: BOTANY, VOLUME 24 flat or becoming involute, tapering to a fine point, scabrous on the upper surface and bearing scattered long white hairs; panicles 5-20 cm. long, finally long ex- serted, the short, stiff, rather distant, ascending to spreading branches floriferous to the base, bearing scattered long fine hairs; glumes narrow, acuminate, subequal, 5-7 mm. long, glabrous; lemma gradually narrowed into a curved or flexuous awn, the lemma and awn together 15-35 mm. long, the division indistinct, the lateral awns wanting. Aristida laxa Cav. Icon. PI. 5: 44. pi. J+70, f. i. 1799. A. spadicea H.B.K. Nov. Gen. & Sp. 1: 123. 1815. Chaetaria spadicea Roem. & Schult. Syst. Veg. 2: 397. 1817. Aristida lagascae Henr. Med. Rijks Herb. Leiden 54: 281. 1927. This species has been credited to British Honduras by A. S. Hitchcock (Contr. U. S. Nat. Herb. 24: 601. 1930) but no specimen has been observed by the author. Mexico; Honduras; Nicaragua; Colombia; Ecuador. Resembling A. hamulosa, but the panicles larger with long drooping branches, and the summit of the lemma with a twisted neck 3-5 mm. long. Aristida longifolia Trin. Me"m. Acad. St. Pe"tersb. VI. Math. Phys. Nat. 1:84. 1830. Wet sand at edge of stream; Rio On, Mountain Pine Ridge, El Cayo District, British Honduras, Lundell 6801. Northeastern Brazil. Perennial; culms tufted, about 60 cm. high, erect; sheaths compressed, gla- brous, the lower ones crowded; blades elongate, 2-3 mm. wide, attenuate, firm, strongly nerved, glabrous beneath, scabrous and sometimes sparsely pilose above; panicle more than half the length of the culm, the distant branches ascending or spreading, bearing a few appressed spikelets toward the ends; glumes 10-12 mm. long, acuminate, subequal or the second a little longer than the first; lemma about 10 mm. long, the central awn 2-3 cm. long, the lateral half to two-thirds as long, suberect, scabrous. Aristida orizabensis Fourn. Mex. PI. 2: 78. 1886. A. pseudo- spadicea Hubb. Proc. Amer. Acad. 49: 500. 1913. A. orizabensis var. pseudospadicea Henr. Med. Rijks Herb. Leiden 54B: 473. 1928. Oak and pine forests, brushy rocky slopes, and dry places, 850-2,200 meters; Jalapa; Jutiapa; Guatemala; Chimaltenango; Huehuetenango. British Honduras; Mexico; El Salvador; Hon- duras; Costa Rica; Panama. Perennial; culms slender, 50 cm. to more than 1 meter high, smaller in de- pauperate plants, glabrous; blades 10-30 cm. long, 1-3 mm. wide, scabrous on the upper surface, flat at the base, becoming involute pointed, the older ones at the base of the plant finally flattened and coiled; panicles 15-30 cm. long, the branches SW ALLEN: GRASSES OF GUATEMALA 35 distant, the upper ones appressed, the lower ones often spreading, somewhat flexuous, usually less than 8 cm. long; spikelets appressed to the branches; glumes 8-10 mm. long, narrow, acuminate, awn-pointed, the second a little longer than the first; lemma 8-12 mm. long with a slender twisted beak about 3 mm. long; awns 1-2.5 cm. long, about equally divergent, the central a little longer than the lateral ones. Aristida purpurascens Poir. in Lam. Encycl. Suppl. 1: 452. 1810. Chaetaria purpurascens Beauv. Ess. Agrost. 30, 152, 158. 1812. Common in sandy pinelands, British Honduras. Not known from Guatemala. Southeastern United States. Perennial; culms mostly 40-70 cm. high, erect, the base slender and rather weak; sheaths somewhat compressed, glabrous or nearly so, especially the lower ones overlapping; blades usually 10-20 cm. long, less than 2 mm. wide, flat, more or less flexuous, scabrous above with a few hairs toward the base; panicles narrow, rather lax, as much as half the length of the culm, the branches appressed, usually 1-2 cm. long; glumes subequal, 5-8 mm. long, rarely longer, usually mucronate; lemma 5-7 mm. long, the body glabrous, the callus slightly pubescent; awns equal or the central a little longer, 1.5-2.5 cm. long, equally divergent, horizontally spreading or somewhat reflexed, more or less contorted toward the base. Aristida recurvata H.B.K. Nov. Gen. & Sp. 1: 123. 1815. Chaetaria recurvata Roem. & Schult. Syst. Veg. 2: 397. 1817. Aristida neesiana Trin. & Rupr. M&n. Acad. St. Pe"tersb. VI. Sci. Nat. 5 (1): 113. 1842. A. riedeliana Trin. & Rupr. Mem. Acad. St. Pdtersb. VI. Sci. Nat. 5(1): 114. 1842. Along Rio Privacion, Mountain Pine Ridge, El Cayo District, British Honduras. Not known from Guatemala. Panama; Colom- bia; Venezuela; British Guiana; Peru; Brazil. Densely tufted perennial with numerous old blades flattened and coiled at the base of the plants; culms 60-100 cm. high, relatively slender, glabrous, or scabrous below the panicle; sheaths longer than the internodes, glabrous; blades 15-30 cm. long, 1-3 mm. wide, tapering to a long involute point, glabrous beneath, scaberulous above, with thickened scabrous margins; panicles 10-30 cm. long, narrow, dense, somewhat interrupted, the branches ascending or appressed, re- branching from near the base, the branchlets appressed and dense, giving the panicle a lobed appearance, the lower internodes as much as 3 cm. long, the upper ones gradually shortened; glumes 8-10 mm. long, narrow, acuminate or awn- pointed, the first very scabrous; lemma 3.5-4 mm. long, glabrous, the slender slightly twisted column 2-3 mm. long, the callus blunt, densely pubescent, about 0.4 mm. long; awns 10-12 mm. rarely 15 mm. long, the central slightly longer than the lateral ones, all loosely twisted together at the base, divergent. Aristida schiedeana Trin. & Rupr. Me"m. Acad. St. Pe"tersb. VI. Sci. Nat. 5 (1): 120. 1842. 36 FIELDIANA: BOTANY, VOLUME 24 Grassy or brushy slopes, pine and pine-oak forests, sometimes in cultivated ground, 1,000-2,000 meters; Zacapa; Jalapa; Guate- mala; Sacatepe"quez; Huehuetenango. Mexico. Culms tufted, erect, 30-80 cm. high, several-noded ; sheaths much longer than the internodes, glabrous, or rather conspicuously villous on the collar; blades firm, elongate, attenuate, as much as 3 mm. wide, the lower ones becoming curled with age; panicles open, as much as 30 cm. long, the branches solitary or in pairs, distant, spreading, naked at the base; glumes subequal, 8-10 mm. or as much as 15 mm. long; lemma narrowed into a slender twisted column, 10-15 mm. long including the column; central awn 5-10 mm. long, divergent, the lateral ones minute or obsolete. FIG. 6. Aristida ternipes, X 1. Aristida ternipes Cav. Icon. PI. 5: 46. 1799. Streptachne scabra H.B.K. Nov. Gen. & Sp. 1 : 124. pi. 40. 1815. S. tennis H.B.K. Nov. Gen. & Sp. 1: 124. 1815. Aristida scabra Kunth, Rev. Gram. 1: 62. 1829. Ortachne scabra Fourn. Bull. Soc. Bot. France 27: 295. 1880. Figure 6. Hills, thickets, and brushy fields, up to 1,200 meters; Zacapa; Jutiapa; Santa Rosa; Guatemala. British Honduras; southwestern United States to Colombia; Cuba; Bahamas. Perennial; culms in small tufts, erect, 50-150 cm. high; blades flat, elongate, flexuous, involute toward the tip, tapering into a fine point; panicles large, diffuse, drooping, one-third to one-half the length of the culm, the branches relatively SWALLEN: GRASSES OF GUATEMALA 37 stout, scabrous, naked below; spikelets appressed toward the ends of the branches; glumes 8-10 mm. long; lemma 15-18 mm. long, including the flattened and tapering summit, scabrous on the keel, the central awn subterete, straight or arcuate, 10-15 mm. long, the lateral awns usually less than 1 mm. long. ARTHRAXON Beauv. Perfect spikelets sessile, the secondary spikelet and its pedicel wanting or rarely present at the lower joints of the articulate rachis; fertile lemma entire or minutely bidentate, awned from the back above the base. Slender annuals with cordate blades and few paniculate racemes. Species about 20, in the tropics of the Old World; introduced in America. FIG. 7. Arthraxon quartinianus, X 38 FIELDIANA: BOTANY, VOLUME 24 Arthraxon quart inianus (A. Rich.) Nash, N. Amer. Fl. 17: 99. 1912. Arthraxon ciliaris subsp. quartinianus Hack, in D.C. Monog. Phan. 6: 356. 1889. Figure 7. Moist thickets and banks, Huehuetenango ; Quezaltenango. Mexico (Chiapas). West Indies. Introduced from the tropics of the Old World. Annual; culms very slender, creeping, freely branching; sheaths much shorter than the internodes, papillose or papillose-pilose especially toward the summit; blades ovate, subcordate, 1-4 cm. long, 4-12 mm. wide, sparsely hispid with long hairs; racemes 1-3 on very slender peduncles, mostly 1-2 cm. long; spikelets 3 mm. long, pale or usually purplish, acute, hispid near the tip, the awn 3-5 mm. long. f- ARTHROSTYLIDIUM Rupr. Caespitose, unarmed bamboos with determinate rhizomes and erect or climb- ing, often apically pendulous culms; the branches either numerous, slender and subequal or few and very unequal, the central one at each node then strongly dominant and flanked by one to several pairs of progressively shorter and more slender ones; the culm sheaths sooner or later deciduous in most species; leaf blades typically without conspicuous transverse veins. Inflorescences spicate, racemose or paniculate, the spikelets several-many-flowered, usually readily disarticulating when mature; empty glumes 1-several; lodicules typically 3; stamens 3; style 1, sometimes divided almost to the base, stigmas usually 2; fruit a caryopsis. About 35 species have been named; all are native to tropical America. As a rule, they are of no great economic importance. Three clearly distinct species have been found in Guatemala. Branches few at each culm node, unequal; spikelets distant A. excelsum. Branches numerous at each culm node, slender, subequal; spikelets approximate. Spikelets conspicuously flattened, not crowded, lemma tightly amplectant, mucronate A. bartlettii. Spikelets not conspicuously flattened, somewhat crowded, lemmas loosely amplectant, aristate A. pittieri. Arthrostylidium bartlettii McClure, Phytologia 5: 81-82. 1954. Known only from the type (Bartlett 12154) from the "jungle near a dry arroyo at Uaxactun," and one other collection from the vicinity of La Libertad, Pete"n. The recorded data are very meager. Culms of unknown height, the upper internodes to 29 cm. X 3 mm., thin- walled, glabrous; nodes scarcely inflated; culm sheaths deciduous (lacking in the type); branches numerous, very slender, subequal, rebranched with solitary twigs at basal nodes and occasionally at the upper ones, 5-35 cm. long; leaf sheaths SWALLEN: GRASSES OF GUATEMALA 39 very slender, compressed-keeled and with nerves salient below the insertion of the petiole, puberulent here and there along the ciliate margins, otherwise glabrous or nearly so; auricles lacking; oral setae lacking, or few and weakly developed, glabrous; petiole collar only slightly flared, the margin arcuate, entire; ligule short, not exceeding 1 mm., the apex usually convex, the margin ciliolate; petiole very short (2-3 mm.), slender, scabrous on the upper surface, glabrous or nearly so on the lower surface, dark brown and very brittle when dry; leaf blades 20-120 X 2-9 mm., lanceolate to oblong-lanceolate, acute, rounded at the base, pli- catulate, scabrous throughout on the upper surface, lightly glaucous except along one edge on the lower surface, hirsute on one side at the base only, otherwise glabrous or weakly asperous on the lower surface, the midrib and primary veins scarcely discernible on the upper surface, weakly so on the lower surface. Inflorescences subspicate racemes terminating leafy or leafless branches of first or second order, exserted 5-16 cm., the main axis glabrous; spikelets some- what flattened, 15-20 mm. long, subsessile, the pedicels about 1 mm. long, ap- pressed, about 10 mm. apart on the rachis; empty glumes 2 or 3, glabrous, keeled, mucronate or more commonly scabro-aristate, I: narrowly triangular, 2.5-3 mm. long, 1-3 nerved, II: triangular, acute, 3-5 mm. long, 3-5 nerved, III: lanceolate, acute, 5-6 mm. long, 5-7 nerved; florets 1.5-3.5, somewhat flattened and slightly divergent, the lowest one sometimes incomplete, the uppermost always tabescent; rachilla segments one-half to two-thirds as long as the palea, slender, abruptly flared at the cupulate apex, glabrous (the uppermost one scabrous) below, the cupule white-strigose with ciliolate margin; lemmas thin, pale, stramineous, about 5-9-nerved, lanceolate, acute, scabro-mucronate, ciliolate along the margins above, otherwise glabrous, I: about 6 mm. long, sometimes sterile, II and III: 8-10 mm. long; palea generally exserted 1-3 mm., commonly tinted with wine, ciliate at the apex and on the keels near the apex, otherwise glabrous; lodicules 3, similar, about 1 mm. long, lanceolate, acute, hyaline, with inconspicuous nerves, sparsely ciliolate at the apex; anthers greenish yellow, about 5 mm. long; ovary slender subfusiform, glabrous, pale brown, about 1.5 mm. long, passing above into a white, glabrous style crowned by 2 plumose stigmas. Fruit not seen. Arthrostylidium excelsum Griseb., Fl. Brit. W. Ind. 529. 1864. Plant of dense, wet forests at elevations of 1,500-1,600 meters; Alta Verapaz; Zacapa. Dominican Republic (whence the type). "Small, slender vine" (Standley), "shrubby" (Steyermark). Culms (not present in the type; described from Steyermark 42626) forming caespitose clumps, slender, to 2.5 mm. in diameter at the base, stiff, the internodes glabrous, shining (III: up to 93 mm. X 2 mm.); nodes slightly swollen, all gemmiferous. Culm sheaths apparently more or less persistent (represented in Steyermark 42626 by decaying fragments). Branches solitary or the principal one flanked by usually two smaller ones, the principal one to 45 cm. long, appressed to ascending, the internodes elongate (to 12 cm. X 1-1.5 mm.), glabrous, glossy, the nodes some- what inflated. Leaf sheaths lightly compressed-keeled, salient-nerved, glabrous or nearly so dorsally and on the margins; auricles lacking; oral setae few to several, approximate, parallel, antrorse-erect throughout or the tips bent back, glabrous, persistent, at first chestnut brown gradually fading to stramineous; petiole collar 40 FIELDIANA: BOTANY, VOLUME 24 only slightly flared, the apex straight to faintly emarginate, the margin entire or nearly so; leaf blades 7.5 cm. X 11 mm. to 15 cm. X 23 mm., lanceolate to linear-lanceolate, acuminate, often apiculate, rounded to cuneate-rounded at the base, white strigose at the base and above this antrorse-scabrous near the outer margin on the upper surface, microscopically papillose between the nerves on the lower surface, otherwise glabrous or nearly so on both surfaces, sometimes antrorse- scabrous on the lower surface near the apex, often plicatulate, the midrib and nerves inconspicuous on both surfaces. Inflorescence a slender raceme terminal to leafy branches or leafless, appressed twigs, exserted 15-20 cm., the stiff, sulcate axis nearly straight throughout or zigzag above (geniculate at the point of insertion of each of the penultimate 2-3 pedicels), entirely glabrous; spikelets distant, subsessile, appressed or divaricate, flattened, somewhat lax; pedicels about 1 mm. long, appressed, glabrous, 10-25 mm. apart; empty glumes usually 3, stramineous, glabrous, few-nerved, mu- cronate or submucronate, I: about 4 mm., II: about 5 mm., Ill: about 6 mm. long; rachilla segments strongly compressed, sulcate-striate when dry, flaring to the cupulate apex, obscurely ciliolate on the margin of the cupule, otherwise glabrous, the lower ones two-fifths, the upper ones two-thirds as long as the lemma; florets usually 5-6, the uppermost tabescent; lemmas 8-10 mm. long, nerve-keeled toward the acute, submucronate tip, with a strong tendency to roll inward along the margins, greenish stramineous often touched with wine, and showing about 11 colorless veins, glabrous or obscurely strigose throughout, or more commonly coarsely so only along the margins near the base on the outside, white sericeous toward the apex on the inner surface; palea not at all or only slightly exserted, the keels ciliolate toward the truncate, densely ciliate apex, sometimes sparsely sericeous toward the apex between the keels, otherwise glabrous throughout, weakly veined, the margins thick and gaping below, membranaceous and slightly overlapped above; lodicules 2 and subequal or 3 and very unequal, 1.5-2 mm. long, narrowly triangular to lanceolate to oblong, acute to acuminate to abruptly acuminate, thickish and soft, brown, opaque, minutely ciliolate on the margins, otherwise glabrous; anthers not seen; ovary 1 mm. long, linear, glabrous, crowned by a slender, white, glabrous style about 1 mm. long, divided at the top into two irregularly branched stigmas; fruit not seen. Arthrostylidium pittieri Hack. Oesterr. Bot. Zeitschr. 53: 75. 1903. Plant with apparent preference for shade and moist atmosphere, found in forests, in deep ravines and on wet cliffs; Santa Rosa; Jalapa. Costa Rica (whence the type) and Panama. The following description is based on specimens from Guatemala matched with material from the type collection. Densely caespitose plant with apically scandent culms 5-8 meters tall and 1-2 cm. in diameter, the internodes elongate, thin-walled, glabrous, not sulcate above the insertion of the branches, the nodes not inflated; culm sheaths deciduous, unknown; branches very numerous, all slender, up to 50 cm. long, rebranched with usually solitary twigs at basal and (more rarely) other nodes; leaf sheaths short, narrow, with somewhat salient veins, ciliolate on the margins, otherwise SWALLEN: GRASSES OF GUATEMALA 41 glabrous, or roughish between the veins; auricles not at all developed; oral setae absent or few; petiole collar scarcely flared, the apex straight, the margin glabrous; ligule up to 1.5 mm. long, broadly convex at the apex, sparsely ciliolate on the margin, dorsally glabrous; petiole 2-3 mm. long, glabrous on both surfaces, very brittle when dry; leaf blade up to 120 X 18 mm., lanceolate, acute above, broadly rounded to cuneate at the base, midrib salient at the base, otherwise scarcely distinguishable from the very obscure secondary veins; inflorescences mostly secund, spicate racemes, terminal to leafy or (rarely) leafless branches, exserted 6-15 cm., the axis slender, glabrous; pedicels about 1 mm. long, inserted about 5 mm. apart, appressed; spikelets pale stramineous, imbricate, usually bearing 2 or 3 functional florets, the terminal floret tabescent; rachilla segments often tardily disarticulating; empty glumes 3 or 2, glabrous, I (sometimes lacking): subulate, 2-3 mm. long, 1-nerved, II: 4-5 mm. long, ovate-acuminate, 3-5-nerved, mu- cronate or aristate, III: 5-8 mm. long, keeled ovate-lanceolate, or aristate, 5-7- nerved; lemmas lanceolate, acuminate, aristate, 10-15 mm. long, 5-7-nerved, glabrous or nearly so on the back, the margins conspicuously ciliate below the scabrous awn; paleas exserted, ciliate on the keels near the apex; lodicules 2; stamens not seen; ovary linear, about 1 mm. long, glabrous; style 1, stigmas 3; mature fruit unknown. The mature culms of a bamboo of this genus called "carrizo" are used in the vicinity of Lake Atitlan for finishing the walls and par- titions of peasant homes. The whole, unsplit culms are fastened in close order to the horizontal members of the frame by means of bark lashings. Within the household, the long hollow internodes are used to make flutes, and fire-blowing tubes (fuquneras), a simple substitute for the bellows, useful in starting or reviving fires. ARUNDINARIA Michx. Dumetose bamboos with indeterminate, cylindrical rhizomes and erect culms, the culm sheaths persistent or deciduous, the branches solitary or, when fascicled, the central one at each node strongly dominant and flanked by one or more pairs of progressively shorter and more slender ones, the leaf blades with conspicuously and regularly tessellate venation. Inflorescences racemose or paniculate, the spike- lets several- to many-flowered; lodicules 3; stamens 3; style solitary, the stigmas usually 3; fruit a caryopsis. Probably upward of one hundred species, found principally in southeastern Asia and adjacent islands, Japan to Madagascar, have been assigned to this genus. Two of doubtful generic affinity have been described from Africa. The greatest concentration of species of Arundinaria is found in Japan, where apparently a good deal of natural hybridization has taken place. Two species, including the type of the genus, and several varieties, have been described from southeastern United States. The bamboos native of the Western Hemisphere outside of the United States that have been placed in this genus apparently belong elsewhere. Tab. VI. FIG. 8. Arundinaria simonii (Carr.) A. and C. Riv. A, portion of culm, bearing persistent sheath from which the blade has fallen away, X K; B, mid-culm branch complement, X K; C, upper-culm branch complement with leaves, X K; D, junction of leaf sheath and petiole of leaf blade, showing ligule and oral setae, X 2.5; E, portion of inflorescence, X K; F, floret, with two segments of the rachilla, X IK; G, Gl, lower empty glume, X IK; H, HI, upper empty glume, X IK; I, II, lemma, X IK; K, Kl, K2, KB, palea, X IK; L, LI, lodicules, X 3; M, Ml, stamen, X 3; N, pistil, X 3. From Nakai, Flora Sylvatica Koreana, Part xx, pi vi. 1933. 42 SW ALLEN: GRASSES OF GUATEMALA 43 The genus is represented in Guatemala by two introduced species. Branches solitary or nearly so; auricles and oral setae well developed on both culm sheaths and leaf sheaths, the oral setae dark, scabrous; leaf blades broad. A. longiaurita. Branches fascicled; auricles and oral setae lacking entirely on culm sheaths, oral setae lacking or weakly developed on leaf sheaths, pale, glabrous; leaf blades narrow A. simonii. Arundinaria longiaurita Hand.-Mzt. Symb. Sin. 7 (5): 1271. 1936. Indocalamus longiauritus Hand.-Mzt. Anz. Akad. Wiss. Math. Naturw. (Wien) 62: 254. 1926. A Chinese species introduced into the Western Hemisphere by the United States Department of Agriculture. Plants from this source were introduced into Guatemala by Dr. Wilson Popenoe and established at Sr. Pedro Cofino's plantation, Finca Pintado (elev. about 1,547 meters), near Antigua, Suchitepe"quez. The following description is based on the plant as it was found growing at Finca Pintado, in May, 1948 (McClure no. 21655). A small bamboo, with slender, wide-ranging rhizomes, and stiff culms up to about 1 meter tall and 3-6 mm. in diameter; internodes up to 15 cm. long, thick- walled, pale fawn velutinous for some distance below the nodes, gradually gla- brescent; nodes flaring abruptly at the sheath scar and appreciably inflated above it, particularly when geniculate. Culm sheaths persistent, striate with salient nerves, glabrous on the back, prominently ciliate on the upper margins; oral setae strongly developed, delicate, fugaceous, long, slender, falcate, bearing numerous long, spreading, dark, scabrous, oral setae; ligule very short, long-fimbriate on the margin with coarse, scabrous bristles; sheath blades lanceolate, appressed to the culm at first, later usually more or less strongly reflexed, salient- veined, glabrous or nearly so on both surfaces, usually abscissile at length. Branches short, appressed, mostly solitary, sometimes once-branched at the basal and other nodes. Leaf sheaths coarse, closely imbricate, salient- veined, glabrous or fawn velutinous on the back, ciliate on the outer margin, fringed at the base with a dense band of spreading brown hairs, furnished on one or each shoulder with a long, delicate, falcate, spreading, fugacious, setiferous auricle or furnished on one shoulder with numerous strong, appressed scabrous bristles alone instead of an auricle; petiole collar up to about 1 mm. long, thin, densely ciliolate along the irregular margin; ligule very short, not exserted, fringed on the margin with numerous, close-set cilia; petiole long, thick, glabrous or glabrescent; leaf blades lanceolate or oblong- lanceolate, acuminate above, broadly or cuneately rounded at the base, glabrous or nearly so on both surfaces, midrib and primary veins salient on the lower surface, often more or less depressed on the upper surface. In its native habitat, this bamboo produces culms up to 4 meters tall and 15 mm. in diameter, with very long, straight, thick- walled internodes which find many uses locally. The leaves of such plants are very large (up to 30 or 35 cm. long and 7 or 8 cm. broad) and are 44 FIELDIANA: BOTANY, VOLUME 24 much used locally for lining (rain-proofing) bamboo hats and the awning of boats. Arundinaria simonii (Carr.) A. & C. Riv. Bull. Soc. Acclim. Ill: 5: 774. 1878. Pleioblastus simoni (Carr.) Nakai, Jour. Arn. Arb. 6: 147. 1925. Figure 8. A Japanese bamboo introduced into Europe nearly a hundred years ago, and from that source it reached the Western Hemisphere through the agency of the United States Department of Agriculture, which sent plants to the Institute Agropecuario Nacional for trial in Guatemala. The plants were established at Labor Ovalle, Que- zaltenango, but have been hindered in their development by the severity of the dry seasons in that area. The species is variable in stature, and horizontal forms with narrower leaves, often striped with white, and with reduced stature occur. This bamboo, in its various forms, is generally considered solely as an ornamental, but the larger form produces culms that have been used as fishing poles, and for making the handles of shuffle-board sticks (in Florida). They make satisfactory garden stakes, though for this purpose they do not last well. The following description is based in part on that of the Rivieres (op. cit.) : A dumetose bamboo with slowly spreading, slender rhizomes and stiffly upright culms reaching a height of 6 to 8 meters and a diameter of 2 cm.; internodes glabrous, shining, with fine, faintly salient ridges, reaching a midculm length of 40 to 45 cm., hollow, the lumen lined with a white pith; the nodes somewhat inflated. Culm sheaths persistent, striate with salient veins, glabrous on the back, ciliate on the margins; auricles and oral setae usually lacking entirely; ligule truncate, up to 3 or 4 mm. long, ciliolate on the margin; sheath blade linear- lanceolate, arch-reflexed, glabrous or nearly so on both surfaces. Branches short, fasciculate, appressed at the base, then spreading, usually suppressed in the lower part of the culm in large plants. Leaf sheaths slender, strongly imbricate, lightly striate with salient veins, glabrous; auricles only slightly or not at all developed; oral setae few, small, pale, glabrous; ligule well developed, truncate or slightly convex at the apex, glabrous or minutely ciliolate on the margin; petiole slender, glabrous; leaf blade linear-lanceolate, acuminate, cuneate at the base, glabrous on the upper surface, lightly glaucous and glabrous or nearly so on the lower surface, the midrib and primary veins salient on the lower surface, scarcely so on the upper surface. ARUNDINELLA Raddi Spikelets short-pediceled in rather dense contracted panicles; glumes acu- minate, the first 3-5-nerved, the second 5-nerved, much longer than the first; sterile lemma acute, 3-5-nerved, a little shorter to a little longer than the first glume, containing a well developed palea; fertile floret much shorter than the sterile lemma, with a short bearded callus and a terminal geniculate awn. SW ALLEN: GRASSES OF GUATEMALA 45 Slender to coarse perennials with narrow blades and small to larger contracted panicles. Species about 45, in the tropics of Asia and America. Awns 2-5 mm. long, tightly twisted below the bend A. confinis. Awns 8-12 mm. long, not twisted. Culms coarse, 1-2.5 meters high; sheaths densely papillose-hispid. A. deppeana. Culms slender, 30-60 cm. high; sheaths glabrous A. berteroniana. Arundinella berteroniana (Schult.) Hitchc. & Chase, Contr. U. S. Nat. Herb. 18: 290. 1917. Trichochloa berteroniana Schult. Mant. 2: 209. 1824. Arundinella peruviana Steud. Syn. PI. Glum. 1: 115. 1854. A. cubensis Griseb. Mem. Amer. Acad. (n. s.) 8: 533. 1862. Damp thickets, open banks, among rocks along streams, up to 1,500 meters; Alta Verapaz; Chiquimula; Jalapa; Quezaltenango; Retalhuleu; San Marcos. British Honduras; West Indies; Mexico to Brazil. Slender perennial; culms densely tufted, erect, 30-60 cm. or sometimes as much as 1 meter high, glabrous, the nodes appressed-pubescent; sheaths glabrous, sparsely hispid in the throat and on the collar, the margins glabrous or ciliate; ligule ciliate, very short; blades commonly 10-20 cm. long, 2-5 mm. wide, flat or sometimes involute, papillose or papillose-hispid; panicles 10-30 cm. long, rather lax, the ascending branches not densely flowered, floriferous to the base; spikelets 4-5 mm. long, the slender awn of the fertile floret 8-12 mm. long, not twisted below, genic- ulate, the terminal portion spreading or reflexed. Arundinella confinis (Schult.) Hitchc. & Chase, Contr. U. S. Nat. Herb. 18: 290. 1917. Piptatherum confine Schult. Mant. 2: 184. 1824. Arundinella martinicensis Trin. Gram. Pan. 62. 1826. A. pallida Nees, Agrost. Bras. 465. 1829. Figure 9. Prairies and dry slopes at low altitudes; Izabal; Jutiapa. Mex- ico; Costa Rica; Panama; West Indies. Perennial; culms erect, relatively slender, up to 2.5 meters high; sheaths papillose-hispid, papillose only, or glabrate; blades linear, attenuate, flat, com- monly 5-10 mm. wide, scabrous; panicles 20-40 cm. long, densely flowered, sometimes interrupted below, the branches narrowly ascending or appressed; spikelets 4.5-5 mm. long, the awn of the fertile floret commonly 5 mm. long, the lower twisted portion about 2 mm. long, distinctly longer than the sterile lemma. Arundinella deppeana Nees in Steud. Syn. PI. Glum. 1: 115. 1854. A. phragmitoides Griseb. Cat. PL Cuba 234. 1866. Cola de venado (Quezaltenango). FIG. 9. Arundinella confinis. Panicle, X /1>; spikelet and floret, X 10. 46 SW ALLEN: GRASSES OF GUATEMALA 47 Pine forests, brushy slopes, moist thickets, clay hills, and gra- velly banks, up to 1,300 meters; Alta Verapaz; Izabal; Jalapa; Santa Rosa; Guatemala; Retalhuleu; Quezaltenango; San Marcos. British Honduras; West Indies; Mexico to Brazil. Coarse perennial; culms erect, 1-2.5 meters high, glabrous; sheaths all much longer than the internodes, rather firm but loose, densely papillose-hispid with appressed hairs, especially toward the summit; ligule membranaceous, about 0.5 mm. long; blades elongate, attenuate, flat, scabrous and sparsely to densely papillose-hispid; panicles 25-70 cm. long, dense, somewhat interrupted below, the slender straight or commonly flexuous branches in dense closely overlapping fascicles, some naked at the base, the lower ones 10-15 cm. or rarely as much as 25 cm. long; spikelets 4-5 mm. long, appressed; glumes acuminate, the first 3-nerved, the second much longer than the first, 5-nerved; sterile lemma acute; awn of fertile floret about 1 cm. long, geniculate, not twisted, slender and flexuous above the bend. AVENA L. Spikelets 2- or 3-flowered, the rachilla bearded, disarticulating above the glumes and between the florets; glumes about equal, 7- to 9-nerved, longer than the lower floret; lemmas indurate, 5-9-nerved, bidentate, bearing a dorsal, genic- ulate, twisted awn. Annuals with rather broad, flat blades and open panicles of large spikelets. Species about 10, all in the Old World ; introduced in America. Avena fatua L. Sp. PI. 80. 1753. In wheat field, Volcan Zunil, Quezaltenango. Introduced from Europe. Culms erect, 30 cm. to more than 1 meter high, slender to rather coarse, smooth and shining; sheaths smooth, usually shorter than the internodes; blades flat, linear, 4-15 mm. wide, scabrous; panicles 15-30 cm. long, loose, the branches ascending or spreading, more or less flexuous; spikelets 3-flowered on slender curved peduncles; glumes about 2.5 cm. long; lemmas 2 cm. long, the lower part covered with long, stiff, brownish or whitish hairs, the teeth acuminate; awn 3-4 cm. long, geniculate, twisted below. AXONOPUS Beauv. Spikelets solitary, sessile in two rows on one side of the 3-angled rachis, the back of the fruit turned from the rachis; first glume wanting; second glume and sterile lemma equal, often pointed beyond the fruit; fertile lemma and palea indurate, the lemma oblong-elliptic, the margins slightly inrolled. Caespitose or stoloniferous perennials with flat or folded, rounded or pointed blades, and few to several slender racemes, digitate or racemose on the common axis. 48 FIELDIANA: BOTANY, VOLUME 24 Species about 80; tropical and subtropical America. Rachis conspicuously hispid with stiffly spreading golden yellow hairs. .A. aureus. Rachis glabrous or scabrous. Plants stoloniferous. Spikelets 2-2.5 mm. long, the second glume and sterile lemma extending well beyond the fruit; blades commonly 8-10 mm. wide A. compressus. Spikelets 2 mm. long, the second glume and sterile lemma only slightly pointed beyond the fruit; blades commonly 2-4 mm. wide, rarely as much as 5-6 mm. wide A. affinis. Plants not stoloniferous. Second glume and sterile lemma much longer than the fruit; blades lax, 6-10 mm. wide. Sheaths strongly compressed, glabrous A. centralis. Second glume and sterile lemma scarcely exceeding the fruit. Spikelets 3.6-4.2 mm. long A. elongatus. Spikelets not more than 3 mm. long. Plants with usually well-developed scaly rhizomes. Spikelets 2-2.3 mm. long; fruit dark brown A. ciliatifolius. Spikelets 2.5-3 mm. long; fruit pale A. rhizomatosus. Plants caespitose, without rhizomes. Spikelets not more than 2 mm. long A. purpusii. Spikelets 3 mm. long. Spikelets glabrous or nearly so; nodes appressed pubescent. A. poiophyllus. Spikelets densely hairy on the margins; nodes conspicuously bearded. Sheaths and blades rather densely papillose-pilose. . .A. blakei. Axonopus affinis Chase, Jour. Washington Acad. Sci. 28: 180. /. 2. 1938. Moist banks, thickets, swamps, and open ground, sea level to 1,500 meters; Alta Verapaz; Chiquimula. Southeastern United States, Mexico and the West Indies to Argentina. Similar in habit and aspect to A. compressus and formerly included with it; blades narrower, often elongate; spikelets 2 mm. long; second glume and sterile lemma about as long as the fruit, not pointed beyond it. Axonopus aureus Beauv. Ess. Agrost. 12, 154. 1812. Paspalum aureum H.B.K. Nov. Gen. & Sp. 1: 93. 1815. Axonopus pulcher Kuhlm. Comm. Linhas Telegr. Estrat. Matto Grosso 67: 88. 1922. Savannas and pine ridges, 1,200-1,400 meters; Chiquimula. British Honduras (El Cayo, Belize, and Toledo Districts) to Brazil and Bolivia; Puerto Rico; Trinidad. Perennial; culms 35-90 cm. high, rarely more than 1 meter, erect, branching; sheaths compressed, keeled, glabrous, the margins sometimes ciliate; ligule ciliate, SW ALLEN: GRASSES OF GUATEMALA 49 about 0.5 mm. long; blades 4-15 cm. long, 3-9 mm. wide, spreading, firm, flat or drying involute toward the tip, glabrous, the margins scabrous, sometimes sparsely ciliate toward the rounded base; racemes 2-15, slender, ascending, crowded on a short hairy axis; rachis 0.4-0.7 mm. wide, conspicuously papillose-ciliate with stiff golden yellow or brt>wn hairs, bearing below each spikelet a tuft of similar hairs; spikelets 1.3 mm. long, glabrous or sparsely appressed-hispid. Axonopus blakei Hitchc. Proc. Biol. Soc. Washington 40: 85. 1927. Open grassy plains; Izabal (type from Cristina, Blake 7611). Honduras. Perennial; culms densely tufted, erect, about 60 cm. tall, the nodes densely villous with ascending hairs; sheaths pilose, especially toward the summit; blades flat, folded at the base, as much as 25 cm. long, 2-4 mm. wide, papillose-pilose; racemes 3-4, 7-12 cm. long, ascending, pubescent or pilose at the base; spikelets 3 mm. long, the second glume and sterile lemma densely pilose on the margins, sparsely pilose or glabrous on the back, the hairs at the summit as much as 1 mm. long. Axonopus cen trails Chase, Jour. Washington Acad. Sci. 17: 143. 1927. Damp brushy slope, 870 meters; Chiquimula. Honduras; El Salvador; Nicaragua; Panama. Perennial; culms in large clumps, 40-90 cm. high, erect to stiffly spreading, simple, compressed, glabrous; sheaths keeled, usually pubescent on the margins at least toward the summit and on the collar, otherwise glabrous; ligule short, firm, fimbriate; blades 15-50 cm. long, 6-10 mm. wide, flat, or folded at the base, sparsely pubescent on the upper surface, glabrous on the lower, the margins ciliate toward the base; inflorescences terminal and axillary, finally long-exserted ; racemes 2-6, 8-15 cm. long, ascending or spreading, the upper 2 or 3 approximate, the lower remote, the rachis about 0.5 mm. wide, flexuous, minutely scabrous on the margins; spikelets 3 mm. long, oblong, rather distant, the glume and sterile lemma equal, extending beyond the fruit, silky pubescent on the internerves; fruit 2 mm. long, oblong-elliptic, pale. Axonopus ciliatifolius Swallen, Jour. Washington Acad. Sci. 23:458. 1933. Known only from the type, collected at Mountain Pine Ridge, El Cayo District, British Honduras, Bartlett 11746. Culms densely tufted, erect from short scaly rhizomes, 50-70 cm. tall, with terminal and axillary inflorescences; leaves mostly crowded toward the base, the sheaths keeled, sparsely pubescent, the blades flat, 7-16 cm. long (or those on the innovations sometimes longer), 1-2 mm. wide, pilose on both surfaces, the margins papillose-ciliate, especially toward the base; ligule 0.1 mm. long; racemes 2-5, racemose, ascending or appressed, 3-11.5 cm. long; spikelets 2-2.3 mm. long, 50 FIELDIANA: BOTANY, VOLUME 24 glabrous or sparsely pubescent, the second glume and sterile lemma subequal, obtuse, scarcely covering the fruit; fruit dark brown, smooth and shining. Axonopus compressus (Swartz) Beauv. Ess. Agrost. 12. 1812. Milium compressum Swartz, Prodr. Veg. Ind. Occ. 24. 1788. Pas- palum compressum Raspail, Ann. Sci. Nat. 5: 301. 1825. P. laticul- mum Spreng. Syst. Veg. 1: 245. 1825. Anastrophus compressus Schlecht. ex Doell in Mart. Fl. Bras. 2 (2): 102. 1877. Paspalum raunkiaerii Mez, Repert. Sp. Nov. Fedde 15: 60. 1917. Figure 10. Open ground, brushy hillsides, and along roads, usually in moist places, sea level to more than 1,300 meters; Pete"n; Alta Verapaz; Izabal; Huehuetenango; Quezaltenango; Escuintla; Suchitepe"quez. British Honduras; southeastern United States and the West Indies to Argentina; warmer parts of the Old World. Stoloniferous perennial; culms in small tufts, 15-60 cm. high, compressed, erect or ascending, the nodes appressed-pubescent or sometimes bearded; sheaths keeled, glabrous, pubescent on the collar, the margins hyaline, glabrous or ciliate, the lower ones relatively short, much longer than the internodes, the upper one elongate; blades 5-15 cm. long, or those of the innovations elongate, 6-10 mm. wide, rarely as little as 4 mm. or as much as 12 mm. wide, obtuse, rounded at the base, glabrous, the margins usually ciliate at least toward the base; inflorescences terminal and axillary from the upper sheaths, composed of 2-5 ascending or spread- ing racemes, 3-9 cm. long, the upper two conjugate, the others a short distance below; spikelets 2-2.5 mm. long (rarely 3 mm.); second glume and sterile lemma pointed beyond the fruit, glabrous or sparsely pubescent on the internerves; fruit 1.5-2 mm. long, oblong, minutely roughened. Axonopus elongatus Swallen, Contr. U. S. Nat. Herb. 29: 414. 1950. Pine forests, 1,700-2,000 meters; Zacapa (Sierra de las Minas, below Finca Alejandria, Steyermark 29781, type). Perennial, probably with rhizomes; culms erect, about 1 meter tall, glabrous; sheaths longer than the internodes, compressed, keeled, appressed pilose on the margins toward the summit or nearly glabrous, the uppermost elongate, about 40 cm. long; ligule a ciliate membrane 0.5-1 mm. long; blades 23-24 cm. long, 3.5-4.5 mm. wide, flat, firm, scabrous at least on the margins, more or less papil- lose-ciliate at the base; inflorescences terminal and axillary, long-exserted; racemes 2-6, 8-13 cm. long, stiffly ascending, the rachis 0.6 mm. wide, scabrous on the margins; spikelets 3.6-4.2 mm. long, 1.2 mm. wide, the pedicels 0.5 mm. long; second glume and sterile lemma equal, acute, exceeding the fruit, sparsely pilose between the nerves or nearly glabrous, the midnerve of the glume rather prom- inent; fruit 3.2 mm. long, subobtuse, pale, glabrous. Axonopus poiophyllus Chase, Proc. Biol. Soc. Washington 24: 133. 1911. Anastrophus poiophyllus Nash, N. Amer. Fl. 17: 163. 1912. FIG. 10. Axonopus compressiis. Plant, X 1A; two views of spikelet, and floret, X 10. 51 52 FIELDIANA: BOTANY, VOLUME 24 Grassy hills and ravines, at low altitudes; Alta Verapaz (Secan- quim, Cook & Doyle 58, type). Honduras. Perennial; culms densely tufted, erect, as much as 80 cm. tall, the nodes ap- pressed-pilose; basal sheaths crowded, pilose with appressed or spreading hairs, those of the culm elongate, glabrous; blades elongate, flat, conduplicate at the base, 2-7 mm. wide, glabrous, or more or less pilose at the base; inflorescence long-exserted, of 3-4 narrowly ascending racemes; spikelets 3 mm. long, acute, the second glume and sterile lemma slightly exceeding the fruit, glabrous or sparsely pilose on the margins. Axonopus purpusii (Mez) Chase, Jour. Washington Acad. Sci. 17: 144. 1927. Paspalum purpusii Mez, Bot. Jahrb. Engler 56: Beibl. 125: 10. 1921. Savannas and pinelands; Pete"n; Izabal. British Honduras; southern Mexico to Argentina. Perennial; culms very slender, densely tufted, erect, 15-40 cm. high; leaves crowded toward the base, only one about the midculm, this with elongated sheath and reduced blade; sheaths compressed, keeled, glabrous to sparsely pilose with a dense tuft of hairs at the mouth; blades flat, conduplicate at the base, mostly 5-10 cm. long, rarely as much as 20 cm., 1-4 mm. wide, densely hairy on the upper surface toward the base, otherwise sparsely pilose or nearly glabrous; inflorescences terminal and sometimes axillary, composed of 2-4 slender ascending racemes 3-8 cm. long; spikelets 2 mm. long; second glume and sterile lemma somewhat pointed beyond the fruit, the margins stiffly appressed-pilose, the hairs longer at the summit, forming a rather prominent tuft at the tip of the spikelet. Axonopus rhizomatosus Swallen, Jour. Washington Acad. Sci. 23:458. 1933. Open pine forests and pine ridges, up to 1,400 meters; Alta Vera- paz; Izabal. British Honduras (Toledo District); Honduras. Culms caespitose, erect from short scaly rhizomes, 45-85 cm. tall, the nodes densely pubescent; sheaths keeled, rather densely pilose, especially on the collar, or nearly glabrous; blades flat, as much as 25 cm. long, 1-4 mm. wide, the upper- most reduced, not over 2 cm. long, sometimes nearly wanting, smooth or scaber- ulous, more or less pilose toward the base, the margins papillose-ciliate for a short distance at the base; ligule 0.1-0.2 mm. long; racemes 2-4, appressed, 5-13 cm. long, subdigitate with one a short distance below the others; spikelets 2.5-3 mm. long; second glume and sterile lemma equal, acute, slightly exceeding the pale or lead-colored fruit, the margins densely pilose, especially toward the summit. BAMBUSA Schreb. Caespitose, unarmed or spiny-branched bamboos with stout, determinate rhizomes; culms erect or ascending, usually more or less nodding or arched at the tip, but not climbing; culm sheaths promptly deciduous in most species; culm SWALLEN: GRASSES OF GUATEMALA 53 branches rarely solitary in part, usually fasciculate, the central one at each node strongly dominant and flanked by several pairs of progressively shorter, more slender ones; leaf blades without typically tessellate venation. Inflorescences in subsessile pseudospikelets, solitary or more commonly in more or less dense aggregates, at the nodes of very short axes lateral to leafy or more commonly leafless branches, the aggregates usually growing more dense in time, as the buds basal to the pseudospikelets develop, successively, into additional pseudospikelets; spikelets terminal to pseudospikelets and preceded on the same axis by one to three glumes subtending buds; rachilla usually disarticulating more or less readily at maturity; florets several to many, each subtended by a lemma and a two-keeled palea; lodicules usually 3; stamens 6, the filaments filiform and free, or rarely flattened, with some of them more or less firmly adhering at the margins at first (as in B. vulgaris); ovary typically solitary, with a single style and 1-3 plumose stigmas. Fruit a caryopsis. About 85 recognizable species known to science are properly assigned to this genus. All are native to the Old World tropics, their principal center of distribution being in southeastern Asia. A number of those that afford useful raw materials or are desirable ornamental plants have become rather widespread in cultivation. Lower branches spiny B. arundinacea. Lower branches unarmed. Auricles of culm sheath not at all or scarcely developed. Culm internodes solid B. multiplex, H.F. Chinese Goddess. Culm internodes hollow. Culm internodes glabrous (large bamboos, with culms erect to tip). B. oldhami. Culm internodes antrorse-hispid (small bamboos, the culms broadly arched above). Culm internodes green B. multiplex. Culm internodes green-striped yellow. .B. multiplex, H.F. Alphonse Karr. Auricles of culm sheaths more or less well developed. Lower culm sheaths narrowly subtriangular, the sheath blade with a long, slender tip. Culm sheath proper truncate at apex B. textilis. Culm sheath proper broadly convex at apex. Culm internodes always cylindrical; small branches at the nodes relatively few; culm sheaths drying nearly flat B. tuldoides. Culm internodes often more or less shortened and flask-shaped; twigs at culm nodes very numerous, the principal branch very long; culm sheaths drying with margins inrolled B. ventricosa. Lower culm sheaths relatively short and broad, not narrowly triangular; the sheath blade relatively short, abruptly acuminate at apex. Sheath blade much narrower than the apex of the sheath proper, auricles equal, falcate spreading. Culms and branches green B. vulgaris. 54 FIELDIANA: BOTANY, VOLUME 24 Culms and branches green-striped yellow B. vulgaris, H.F. vittata. Sheath blade as wide as the apex of the sheath proper, auricles dissimilar, one orbicular, the other oblong decurrent. Culm internodes glabrous B. tulda. Culm internodes more or less conspicuously scabrous below the nodes. B. longispiculata. Bambusa arundinacea Willd. sensu Gamble, J. S., Ann. Roy. Bot. Card. Calcutta 7: 51. pi. 48. 1896. Although the name here used cannot be given authentic legal standing as applied to this bamboo, it is the one most consistently used in the literature for over a hundred years; cf. F. A. McClure, The genus Bambusa and its first-known species. Blumea, Suppl. 111:90-112. 1946. The Giant Thorny Bamboo native and widely cultivated in India, where it is important as a source of structural materials; commonly planted to form living barriers around villages. Introduced here and there, but apparently nowhere abundant, in the tropics of both hemi- spheres. Propagating material from the United Fruit Company's Botanic Garden at Lancetilla, Honduras, introduced into Guate- mala in 1946 by the Institute Agropecuario Nacional, has been established at Finca Chocola, Suchitepe"quez, for observation and trial. Clumps densely compact; the culms here reaching a height of 20 or 25 meters and a diameter of 10 or 15 cm., erect to the tip, or more commonly broadly arched above; the internodes relatively short, glabrous, the basal ones very thick- walled (to about 2 cm.), the middle ones only moderately so (to about 1 cm.), the lower nodes prominent, fringed at first with stiff brown hairs; culm sheaths deciduous (somewhat tardily so at the basal nodes), leathery, with a zone of brown hairs along the base, otherwise dorsally glabrous; auricles and oral setae not at all developed; sheath blades broadly triangular, appressed (reflexed at the upper nodes), persistent, densely strigose with coarse black hairs on the inner surface, glabrous on the outer surface; branches thorny, solitary and very long in the lower part of the culm, then in 2's and 3's, and shorter, above; leaf sheaths glabrous or sparsely hispid; auricles and oral setae irregularly developed, the latter fugacious; leaf blades linear-lanceolate, acuminate, up to 20 X 2.5 cm., glabrous or with a few long hairs near the base on the upper surface, glabrous or puberulent on the lower surface. Bambusa longispiculata Gamble ex Brandis, Indian Trees 668. 1906. Native of India, introduced into the Western Hemisphere by the United States Department of Agriculture. The Institute Agrope- cuario Nacional secured from the Federal Experiment Station at SW ALLEN: GRASSES OF GUATEMALA 55 Mayaguez, Puerto Rico, propagating material for the bamboo col- lection at Finca Chocola, Suchitepe'quez, where it is now well established. In appearance and morphological characteristics this bamboo is closely similar to Bambusa tulda, from which it may be distinguished in the field by the pubes- cent, aciculate surface of the lower internodes of the culm. Besides this, the clump growth is somewhat more open, and the ultimate mature culm stature is smaller (culms reach a height of 12 or 15 meters and a diameter of about 5 cm. under favorable conditions), and the culm walls are relatively thinner. This species was set up by Gamble principally on the basis of the unusual length of the spikelets, which are said to reach 4 inches (10 cm.). Also established at Finca Chocola is a form of this bamboo which differs from the species in having the culms and culm sheaths variegated with vertical stripes of a greenish cream tint. Bambusa multiplex (Lour.) Raeusch. ex Schult. Syst. Veg. 7: 1350. 1830. B. nana Roxb. Fl. Ind. 2: 199. 1832. Native of China; pantropic in cultivation, principally as an ornamental. Introduced by the Institute Agropecuario Nacional from the Experiment Gardens, Canal Zone, and established at Finca Chocola, Suchitepe'quez, for trial in the local economy. Usually a small bamboo, in densely crowded clumps, the culms ascending (rarely erect), straight or broadly arched, commonly 3-4 meters tall and 1.5-2 cm. in diameter, rarely 9 meters tall and 2.5 cm. in diameter, the internodes relatively long (up to 60 cm.), hollow, thin-walled, the surface antrorse-hispid and aciculate; nodes very slightly or not at all flared at the sheath scar, not at all inflated. Culm sheaths somewhat tardily deciduous, glabrous, narrowly trian- gular; auricles and oral setae not at all or only slightly developed; the sheath blade appressed, abscissile, usually antrorse-hispid on both surfaces, then glabres- cent. Branches very numerous and relatively slender. Leaf sheaths glabrous; auricles and oral setae absent or weakly developed; leaf blades linear-lanceolate, of variable size, sometimes to 15 X 2 cm., glabrous on the upper surface, conspic- uously glaucous and pubescent on the lower surface. Horticultural Form, Alphonse Karr. A native of China, this bamboo occurs rarely as a garden plant in Guatemala City. The history of its introduction is not known. This form differs from the species, Bambusa multiplex, principally in the coloration of the culms and branches and their sheaths, which are typically green-striped yellow. In the young shoots, this color- ation is often tinged with a flush of pink. This form has been observed to revert to the species, losing its distinctive coloration completely. 56 FIELDI ANA: BOTANY, VOLUME 24 Horticultural Form, Chinese Goddess. Native of China, pantropic in cultivation, as an ornamental. Introduced by the Institute Agropecuario Nacional from the United States Department of Agriculture collection at Savannah, Georgia, and established at Finca Chocola, Suchitepe"quez, for trial. Distinguished from Bambusa multiplex by its small stature (culms here scarcely exceeding 1.5 meters), the solid (not fistulose), glabrous internodes, and the more numerous, very small leaf blades (common- ly 15-30 X 3-5 mm., rarely 50 X 10 mm.). Bambusa oldhami Munro, Trans. Linn. Soc. 26: 109. 1868. Sinocalamus oldhami (Munro) McClure, Lingnan Univ. Sci. Bull. 9: 67. 1940. Native of Formosa, early introduced into the United States through the agency of private West Coast horticulturists, and now commonly cultivated in California and Florida as an ornamental, under the misapplied name Dendrocalamus latiflorus. Frequent in Lima, Peru, as an ornamental; otherwise rarely seen in the Western Hemisphere outside of the United States and Puerto Rico. Prop- agating material from the Federal Experiment Station at Maya- guez, Puerto Rico, was introduced by the Institute Agropecuario Nacional, and established at Finca Chocola, Suchitepe"quez, for trial in the local economy. Clump compact, slow-spreading, the culms very erect almost or quite to the tip, somewhat sinuous, the internodes of moderate length, glabrous, the wood about one cm. thick, the nodes only slightly inflated. Culm sheaths promptly deciduous, oblong, rounded at the shoulders, irregularly appressed brown-seri- ceous, gradually glabrescent; the auricles and oral setae rather small when present; sheath blade broadly subtriangular with concave sides, apically acuminate, ap- pressed, abscissile, lightly antrorse-hispid on the inner surface, glabrous on the outer surface. Branches few, irregularly developed, coarse, relatively short, the central one at each node often tardily developed and often rooting spontaneously at the bulbous base in older culms. Leaf sheaths glabrous or sparsely hispidulous; auricles and oral setae usually lacking; leaf blades oblong-lanceolate, abruptly acuminate, up to 22 X 3 cm., glabrous on the upper surface, puberulent at first, then glabrescent, on the lower surface. Bambusa textilis McClure, Lingnan Univ. Sci. Bull. 9: 14. 1940. A cultivated bamboo, presumably native of southern China, whence it was introduced into the Western Hemisphere by the United States Department of Agriculture. From the Federal Ex- periment Station at Mayaguez, Puerto Rico, the Institute Agro- pecuario Nacional secured propagating material for the collection J SW ALLEN: GRASSES OF GUATEMALA 57 at Finca Chocola, Suchitepe"quez, where it is under trial. In southern China, this bamboo is one of the most useful species, being one of the principal sources of withes for weaving basketry and matting, and for fabricating cables for towing boats. It is also much used in making furniture. Small culms from plants grown under un- favorable conditions are much used, and are very durable, as garden stakes, and for making picket fences. The plant is a very desirable garden ornamental. Clumps compact, with erect culms reaching, under favorable conditions, a height of 12 meters and a diameter of 5 cm., the internodes up to 40 cm. or more in length, hollow, relatively thin-walled (about 5 mm.), antrorse-hispid, aciculate, the nodes not inflated but flaring appreciably at the sheath scar. Culm sheaths promptly deciduous (drying nearly flat), glabrous or nearly so in mature plants (pubescent at first in young ones), narrowly subtriangular; auricles and oral setae slightly to moderately well developed; sheath blade narrowly triangular or ovate- lanceolate, basally nearly as wide as the apex of the sheath proper, appressed, partially abscissile, antrorse-hispid or subglabrous on the inner surface, sometimes sparsely strewn with acicular appressed hairs near the base, otherwise glabrous on the outer surface. Branches beginning to develop only some months after the culm reaches its full height, numerous, slender, the central one less markedly dominant than in most species of the genus; the branch complement, and the bud from which it arises, lacking at all nodes in the lower one-half or so of culms in mature clumps. Leaf sheaths slender, glabrous or glabrescent, auricles and oral setae usually well developed, fugacious; leaf blades narrowly ovate-lanceolate, acuminate, 15-20 X 1.2-2 cm., glabrous on the upper surface, lightly glaucous and pubescent throughout on the lower surface. Bambusa tulda Roxb. Fl. Ind. 2: 193. 1832. Native of India, where it is important in the local economy, principally as a source of culms for structural purposes, this bamboo was introduced into the Western Hemisphere by the United States Department of Agriculture. Propagating material was obtained by the Institute Agropecuario Nacional from the Federal Experiment Station at Mayaguez, Puerto Rico, and established in the bamboo collection at Finca Chocola, Suchitep^quez, for trial in the local economy. Clump rather compact, the culms reaching, under favorable conditions, a height of 20 meters and a diameter of 10 cm., ascending or suberect, broadly arched at the tip, the internodes elongate, thick-walled, sometimes nearly solid, entirely glabrous, the lower nodes appreciably inflated. Culm sheaths deciduous, broadly triangular, more or less densely clothed with black, deciduous, acicular hairs, the auricles well developed, strongly unequal, one suborbicular, the other oblong, decurrent, wavy, both fringed with oral setae; sheath blade partially abscissile, subovate, abruptly acuminate above, concave below to conform to the strongly convex apex of the sheath proper. Branches several, strongly unequal. Leaf sheaths usually glabrous, the auricles and oral setae lacking or more often FIG. 11. Bambusa vulgaris Schrad. ex Wendl. 1, leaf-branch, X K; 2, part of flowering branch, X Y. 67 68 FIELDIANA: BOTANY, VOLUME 24 Species about 20, three in the Old World, one in Mexico and Central America, the rest in South America. Plants annual; panicles open, loose; lemmas obtuse B. minor. Plants perennial; panicles contracted, rather dense; lemmas abruptly acute or acuminate B. rotundata. Briza minor L. Sp. PI. 70. 1753. Moist ground along stream northwest of San Marcos, Dept. San Marcos, 2,700-3,800 meters, Steyermark 35738. Europe, introduced in America. Figure 14. Annual; culms weak, erect or ascending, 10-50 cm. high; blades flat, as much as 1 cm. wide, glabrous; panicles as much as 15 cm. long, the branches stiffly ascending to spreading, the branchlets divaricate; spikelets ovate, 3-5 mm. long, 3-8-flowered, the long slender pedicels flexuous; lemmas about 3 mm. long, broad, obtuse, more or less pubescent on the middle of the back. Briza rotundata (H.B.K.) Steud. Syn. PI. Glum. 1: 284. 1854. Bromus rotundatus H.B.K. Nov. Gen. & Sp. 1: 152. 1815. Along trail between Jacaltenango and Todos Santos, Sierra de los Cuchumatanes, Dept. Huehuetenango, 1,500-2,500 meters, Stey- ermark 51869. Mexico. Perennial; culms tufted, erect, 20-60 cm. high; sheaths glabrous, usually shorter than the internodes; blades linear, elongate, 1-3 mm. wide, scaberulous; panicles commonly 2-8 cm. long, rarely longer, rather dense, the short branches stiff or somewhat flexuous, narrowly ascending; spikelets 4-5 mm. long, nearly as broad as long, mostly 8-10-flowered; lemmas about 4 mm. long, broadly ovate, abruptly narrowed to a triangular acuminate tip, mucronate or minutely awned; palea half as long as the lemma, circular, flat. BROMUS L. Spikelets several-flowered, the rachilla disarticulating above the glumes and between the florets; glumes acute, the first 1- or obscurely 3-nerved, the second 3-5-nerved; lemmas keeled, 5-9-nerved, awned from between the teeth of the minutely bifid apex; palea shorter than the lemma, thin, ciliate on the keels, adherent to the caryopsis. Slender perennials with closed sheaths, flat narrow blades, and open panicles of relatively large spikelets. Species about 100, in temperate regions or in the tropics at higher altitudes. First glume narrow, 1-nerved; lemmas pubescent, especially on the margins. B. exaltatus. First glume broader, 3-nerved; lemmas glabrous or nearly so B. laciniatus. FIG. 14. Briza minor. Plant, X Yi; spikelet and floret, X 5. 69 70 FIELDIANA: BOTANY, VOLUME 24 Bromus exaltatus Bernh. Linnaea 15: Litt. 90. 1841. B. subalpinus Rupr. ex Fourn. Mex. PL 2: 128. 1886. Open pine woods, about 3,700 meters; Huehuetenango; Saca- tepe*quez. Mexico; Costa Rica; Panama. Perennial; culms erect from a more or less decumbent base, 0.5 to more than one meter high, retrorsely pilose at the nodes; sheaths longer than the internodes or the upper ones shorter, appressed- or spreading-pilose especially toward the sum- mit; ligule membranaceous, erose, about 1 mm. long; blades flat, mostly 15-30 cm. long, 3-5 mm. wide, rarely wider, scabrous, more or less pilose toward the base; panicles 10-20 cm. long, nodding, the slender drooping branches naked below, bearing 1-3 spikelets; glumes narrow, acuminate, subequal or the second longer, the first 1- or obscurely 3-nerved, 8-12 mm. long; lemmas mostly 12-15 mm. long, acuminate, rather evenly hairy across the back, the awn 4-7 mm. or sometimes as much as 1 cm. long. Bromus laciniatus Beal, Grasses N. Amer. 2: 615. 1896. B. pendulinus Sesse" ex Lag. Gen. & Sp. Nov. 4. 1816. Not B. pendu- linus Schrad., 1810. B. proximus Shear, Bull. Torrey Club 28: 245. 1901. Shady ravines and pine-clad slopes, 2,500-4,200 meters; Guate- mala; Solola; Sacatepe"quez; Huehuetenango; Quezaltenango; San Marcos. Mexico. Similar in aspect to B. exaltatiis; panicles coarser and stiffer; first glume broader, 3-nerved; lemmas glabrous or nearly so. CALAMAGROSTIS Adans. Spikelets 1-flowered, the rachilla disarticulating above the glumes, prolonged beyond the floret in a usually hairy bristle; glumes equal, acute or acuminate; lemma equalling the glumes or usually shorter, awned from the back, the awn straight or geniculate, often tightly twisted below the bend, the callus bearded, the hairs very short to long and copious; palea thin, shorter than the lemma. Slender to rather coarse perennials with firm, flat or involute blades and dense or open panicles of relatively small spikelets. Species probably about 150, in cool or temperate regions or in the tropics at higher altitudes. Culms erect from a creeping base; blades flat at least at the base. Sheaths much shorter than the long internodes; culms more than 1 meter high C. pinetorum. Sheaths usually much longer than the relatively short internodes; culms not more than 60 cm. high C. guatemalensis. Culms densely caespitose, not creeping; blades tightly involute to the base. Ligule very short, not decurrent, at least on the lower leaves; blades densely pilose on the upper surface C. vulcanica. Ligule prominent, decurrent; blades not pilose on the upper surface. C. junciformis. [ SWALLEN: GRASSES OF GUATEMALA 71 Calamagrostis guatemalensis Hitchc. Proc. Biol. Soc. Wash- ington 40: 82. 1927. Oak-pine forests, mostly 2,500-3,000 meters; Sacatepe"quez (type from Volcan Agua, A. S. Hitchcock 9120); Quezaltenango; San Marcos. Perennial; culms erect from a creeping base, 30-60 cm. high, simple or spar- ingly branching; sheaths usually longer than the relatively short internodes, gla- brous or scaberulous; ligule 2-5 mm. long, obtuse, firm, decurrent; blades scabrous, firm, flat, becoming involute, 2-3 mm. wide; panicles 7-12 cm. long, dense, some- times spikelike, the branches ascending or appressed, usually floriferous to the base; spikelets 4-5 mm. long, the glumes equal, acute, scabrous; lemma about 4 mm. long, usually scaberulous, the nerves excurrent in short teeth; awn 3-6 mm. long, attached about one-fourth above the base, geniculate, twisted below the bend, the terminal segment 3-6 mm. long; callus hairs about half as long as the lemma; rachilla 1 mm. long, the hairs 2 mm. long. Calamagrostis junciformis (H.B.K.) Steud. Norn. Bot. ed. 2. 1: 250. 1840. Deyeuxia junciformis H.B.K. Nov. Gen. & Sp. 1: 143. 1815. Near Tunima, Sierra de los Cuchumatanes, Dept. Huehueten- ango, 3,300-3,500 meters, Steyermark 48269. Mexico, the type from Nevado de Toluca. Perennial; culms densely tufted, erect, about 50 cm. high, the leaves mostly crowded in a basal cluster; ligule firm, decurrent, 2 mm. long; blades slender, firm, involute, scabrous, 15-20 cm. long; panicle long-exserted, 10 cm. long, the slender somewhat flexuous branches ascending to spreading, naked below; spike- lets 4-5 mm. long, the glumes acute; lemma equaling or slightly exceeding the glumes, glabrous, minutely toothed; awn attached near the middle, 4-5 mm. long, weakly geniculate, loosely twisted or contorted below the bend; callus bearded, the hairs very short and inconspicuous; rachilla one-third as long as the lemma, plumose, the hairs about 1 mm. long. The description is based entirely on material from Guatemala which does not compare well with Mexican specimens. The dif- ferences do not seem sufficient, however, to consider the Guatemala plants distinct, at least with only the present inadequate material at hand. Calamagrostis pinetorum Swallen, Contr. U. S. Nat. Herb. 29: 406. 1950. Dry pine slopes, 2,100-2,500 meters; El Progreso, the type from near Finca Piamonte, Steyermark 43454; Zacapa. Perennial; culms erect from a rhizome-like base, 120 cm. high, glabrous; sheaths scaberulous, the lower ones longer, the upper ones much shorter than the internodes; ligule 4.5 mm. long, obtuse, decurrent; blades 26-33 cm. long, 5-6 72 FIELDIANA: BOTANY, VOLUME 24 mm. wide, scabrous, the uppermost much shorter and narrower; panicle 16 cm. long, about 3 cm. wide, dense, interrupted below, the branches narrowly ascend- ing, long and short ones intermixed; spikelets 5.5-6 mm. long; glumes subequal, 3-nerved, scabrous; lemma 4 mm. long, scabrous, the nerves excurrent as short awns, the awn inserted 1 mm. above the base, 3 mm. long, geniculate, tightly twisted below the bend, the callus sparsely bearded on the sides with short hairs; palea a little shorter than the lemma; rachilla 1 mm. long, bearded with appressed hairs 0.5 mm. long, bearing a rudimentary second floret 2 mm. long. Calamagrostis vulcanica Swallen, Phytologia 4, no. 7: 424. 1953. Pine forests and open places, summits of volcanos, mostly 3,000- 4,600 meters; Sacatepe"quez; Quezaltenango (type from Volcan de Santa Maria, Skutch 836); San Marcos. Mexico (Volcan Tacana). Figure 15. Perennial; culms densely tufted, erect, 40-80 cm. high; sheaths smooth or nearly so, usually longer than the internodes, the lower ones crowded; ligule very short, not visible from the side on the lower leaves; blades convolute, firm, up to 40 cm. long, more or less curved, smooth or scaberulous on the under surface, strongly nerved and rather densely pilose above, especially toward the base; panicles pyramidal, 8-14 cm. long, the slender, spreading to recurved branches in rather distant fascicles, the lower ones as much as 7 cm. long, naked below the middle; spikelets 6-7 mm. long, the glumes equal, acuminate, 3-5-nerved; lemma 5 mm. long, scabrous, the tip hyaline, the nerves excurrent, awned from about the middle of the back, the awn about 10 mm. long, geniculate, tightly twisted below the bend, appressed pilose; callus hairs dense, about 2 mm. long; rachilla 2 mm. long, densely hairy, the hairs about 2 mm. long. Specimens of this species were formerly referred to C. junciformis, but are readily distinguished by the short ligule, pilose blades, and pilose awn. CATHESTECUM Presl Spikes falling entire, consisting *of three spikelets, the lateral ones 2-flowered, staminate or sterile, rarely pistillate, the upper floret sometimes much reduced; central spikelet 3-flowered, the lower floret usually pistillate, sometimes staminate, very rarely perfect, the upper florets staminate or sterile; first glume short, that of the central spikelet usually flabellate; second glume about as long as the spikelet, acuminate, sometimes minutely lobed and mucronate; lemmas dissimilar, the lower ones cleft about one-fourth their length, the awns from between the lobes equaling or slightly exceeding them, the upper ones deeply cleft, the awns villous in the lower part, extending as much as 3 mm. beyond the lobes; in spikes wholly staminate, the lemmas all alike; palea nearly equaling the lemma, the nerves excurrent in short awns. Annual or perennial grasses, frequently stoloniferous, with relatively short flat blades and 3 to 10 V-shaped or rhomboid, spreading spikes, evenly arranged on opposite sides of the slender flattened axis. FIG. 15. Calamagrostis vulcanica. Plant, about X \i\ spikelets, X \\i\ floret, X 6. 73 74 FIELDIANA: BOTANY, VOLUME 24 Species 6, in southwestern United States, Mexico, and Central America. Lateral spikelets with well-developed, usually staminate florets; blades, at least some of them, commonly more than 2 cm. long, often involute, not becoming curled; stolons comparatively short, conspicuously arching C. erectum. Lateral spikelets imperfectly developed, the florets mostly sterile, the lemmas reduced; blades flat, mostly 1-2 cm. long, rarely longer, becoming curled with age; stolons long, widely spreading, not arching C. brevifolium. Cathestecum brevifolium Swallen, Jour. Washington Acad. Sci. 27: 500. 1937. Pastojueno. Moist open hillsides and rocky slopes, 200-300 meters; Zacapa. Mexico. Perennial, stoloniferous, the stolons slender, wiry, widely spreading, the internodes as much as 12 cm. long (usually less than 10 cm.), not conspicuously arched as in C. erectum; culms in small dense tufts, slender, usually branching, erect or geniculate at the nodes, 5-10 cm. tall (rarely to 15 cm.), glabrous; lower sheaths crowded, glabrous or sparsely pilose with a tuft of long hairs at the mouth, the lowermost densely villous at the base; blades firm, flat, acute, becoming conspicuously curled with age, glabrous on the lower surface, scabrous and pilose on the upper, the margins scabrous, 1-2.5 cm. long (rarely to 5 cm.), 1-2 mm. wide; spikes 3-8, usually purple, spreading, dimorphous as in C. erectum; stam- inate spike: first glume narrow, 1 mm. long; second glume broader, acute or acuminate, usually glabrous or sometimes sparsely pilose on the keel, those of the lateral spikelets 2.5 mm. long, that of the central spikelet 3 mm. long, minutely lobed, mucronate; lower lemmas 3 mm. long, sparsely pilose, shallowly lobed, mucronate from between the lobes, the upper ones 2.5 mm. long, similar to the lower but with somewhat deeper lobes; pistillate spikelets: lateral spikelets im- perfectly developed, the first glume 1 mm. long, the second glume acuminate, 2.5 mm. long, pilose to hirsute-villous on the keel, the florets much reduced, sterile, or the lower one rarely staminate; first glume of central spikelet similar to those of the lateral spikelets, the second 3 mm. long, minutely lobed, mucronate, hirsute-villous at least on the keel, the lower floret pistillate, the lemma 3 mm. long, sparsely pubescent on the back, the lobes one-fourth the length of the lemma, the awns from between the lobes slightly exceeding them, the upper florets staminate or neuter, the lemmas 2.5 mm. long, deeply cleft, the awns extending 1-3 mm. beyond the lobes; stamens 1.3-1.6 mm. long. Cathestecum erectum Vasey & Hack. Bull. Torrey Club 11: 37. pi 45. 1884. Figure 16. Abundant in arenal, Banos de Santa Marta, north of Zacapa, about 200 meters, Standley 73918. Mexico; El Salvador; Honduras. Perennial, stoloniferous, the stolons slender, wiry, conspicuously arching, the internodes elongate; culms in small dense tufts, simple or branching, erect or some- what geniculate-spreading, 15-30 cm. tall, glabrous; lower sheaths crowded, pilose in the throat, the lowermost densely villous at the base, the upper ones more distant, glabrous; ligule ciliate, about 0.3 mm. long; blades flat or commonly FIG. 16. Cathestecum erectum, X 1. 75 76 FIELDIANA: BOTANY, VOLUME 24 loosely involute, 3-6 mm. long, 1-1.5 mm. wide, glabrous on the lower surface, scabrous and sparsely pilose on the upper; spikes usually pale, dimorphous, one form entirely staminate, the other with the lower floret of the central spikelet pistillate, the upper floret and those of the lateral spikelets staminate or neuter, the spikes all of the same kind in a single inflorescence, parts of the same plant (joined by stolons) sometimes with both kinds of spikes; staminate spikes: first glume 1 mm. long, second glume acuminate, glabrous or nearly so, that of the lateral spikelets 3 mm. long, that of the central spikelet about 4 mm. long; lemmas similar, 3 mm. long, glabrous, irregularly lobed, awnless or mucronate; pistillate spikes: glumes villous, otherwise like those of the staminate spikes; lemmas of the lateral spikelets similar, 3 mm. long, glabrous, cleft to the middle, the awns from between the lobes equaling or barely exceeding them, more or less hispid; florets of the central spikelet unlike, the lower lemma glabrous or sparsely pubescent, cleft one-third of the length, the awns from between the lobes glabrous, subequal or the central a little longer, somewhat exceeding the lobes; upper florets similar to those of the lateral spikelets, the awns slightly longer, extending 1-2 mm. beyond the lobes; anthers 2 mm. long. CENCHRUS L. Spikelets sessile, enclosed in spiny burs composed of united sterile branches, the burs falling entire, the body of the bur irregularly lobed, the lobes rigid, the spines barbed; spikelets 1 to several in each bur, usually glabrous; first glume narrow, 1-nerved, much shorter than the spikelet, sometimes wanting; second glume and sterile lemma nearly equal, 3-5-nerved, the lemma enclosing a palea and usually a staminate flower; fruit indurate, the lemma acuminate, the margins thin, flat. Annual with flat blades and terminal racemes of burs. Species about 25, in sandy or arid regions of both hemispheres. Bristles antrorsely scabrous, much exceeding the body of the bur C. pilosus. Bristles retrorsely barbed, not exceeding the body of the bur. Burs not more than 4 mm. wide, densely crowded in a long raceme, the lobes interlocking; first glume obsolete C. brownii. Burs 5-7 mm. wide, not crowded, the lobes usually erect; first glume present. C. echinatus. Cenchrus brownii Roem. & Schult. Syst. Veg. 2: 258. 1817. C. viridis Spreng. Syst. Veg. 1: 301. 1825. C. echinatus var. viridis Spreng. ex Griseb. Fl. Brit. W. Ind. 556. 1864. Figure 17. Thickets, open banks, fields, and waste places, to about 1,000 meters; Pete"n; Alta Verapaz; Izabal; Santa Rosa; Escuintla; Retalhuleu. British Honduras; Florida; West Indies; Mexico to Bolivia and Brazil. Annual; culms erect to decumbent-spreading and rooting at the lower nodes, simple to freely branching; sheaths mostly longer than the internodes, compressed, keeled, glabrous; ligule ciliate, less than 1 mm. long; blades 10-30 cm. long, mostly 6-8 mm., or sometimes as much as 12 mm. wide, scabrous to nearly glabrous; SWALLEN: GRASSES OF GUATEMALA 77 spikes 4-10 cm. long, dense, the axis minutely scabrous or pubescent; burs about 4 mm. wide, subtended by a ring of slender irregular bristles, the lobes pubescent, interlocking; spikelets usually 3 in each bur, 4-4.5 mm. long; first glume obsolete; second glume two-thirds to three-fourths as long as the subequal fruit and sterile lemma; fruit acuminate, minutely roughened, the nerves evident near the tip. FIG. 17. Cenchrus brownii. Bur, two views of spikelet, and floret, X 5. FIG. 18. Cenchrus echinatus. Bur, two views of spikelet, and floret, X 5. Cenchrus echinatus L. Sp. PL 1050. 1753. C. pungens H.B.K. Nov. Gen. & Sp. 1 : 115. 1815. C. macrocarpus Ledeb. ex Steud. Nom. Bot. ed. 2. 1: 317. 1840. C. brevisetus Fourn. Mex. PI. 2: 50. 1886. C. echinatus brevisetus Scribn. in Millsp. Field Mus. Bot. 2: 26. 1900. Mozote. Figure 18. Open banks, sand bars, fields and waste places, especially in sandy soil, up to 1,500 meters; Alta Verapaz; Izabal; Escuintla; Guatemala; Suchitepe"quez; San Marcos. British Honduras; south- ern United States; West Indies; Mexico to Argentina. 78 FIELDIANA: BOTANY, VOLUME 24 Annual; culms erect to geniculate or decumbent-spreading, often rooting at the nodes, branching, as much as 1 meter long, glabrous; sheaths compressed, keeled, glabrous, or ciliate on the margins near the summit; ligule ciliate, 1 mm. long; blades mostly 6-20 cm. long, 3-8 mm. wide, acuminate, more or less pilose; spikes 3-10- cm. long, the axis rather stout, flexuous, scabrous; burs scarcely crowded, 4-7 cm. long, usually broader than long, pubescent, containing 3-6 spikelets, the bristles below the bur fewer and stouter than in C. brownii, the lobes or spines erect to spreading, retrorsely barbed at the tip; spikelets 4.5-6 mm. long; first glume small, narrow, 1-nerved, the second two-thirds to three-fourths as long as the nearly equal fruit and sterile lemma; fruit acuminate, the nerves of the lemma apparent near the tip. Cenchrus pilosus H.B.K. Nov. Gen. & Sp. 1: 116. pi. 36. 1815. C. pallidus Fourn. Mex. PI. 2: 50. 1886. Sand bars and rocky slopes at low altitudes; Izabal; Zacapa. Mexico; El Salvador; Nicaragua; Colombia and Venezuela to Peru. Annual; culms 10 cm. to nearly 1 meter high, erect or decumbent at the base, simple or sparingly branching; blades rather thin, flat, scabrous, or sometimes papillose-pilose, 10-40 cm. long, 6-12 mm. wide; spikes 2-14 cm. long, dense, erect, usually long-exserted on relatively stout peduncles; body of bur about 5 mm. thick, densely pilose, the bristles antrorsely scabrous, much exceeding the bur; spikelets usually 3. CHAETIUM Nees Spikelets short-pedicellate, dorsally compressed, the rachilla between the glumes elongate, the bearded base of the first glume adnate to it, forming a long slender callus; glumes narrow or broad, extending into long awns; sterile lemma short-awned or awn-tipped only; fruit subindurate, the lemma acuminate, pointed or awned, the margins thin, flat, not enclosing the summit of the palea. Perennials with flat blades and dense narrow panicles. Species 3, one in Cuba, one in South America, and one in Mexico and Central America. Chaetium bromoides (Presl) Benth. ex Hemsl. Biol. Centr. Amer. Bot. 3: 503. 1885. Berchtoldia bromoides Presl, Rel. Haenk. 1 : 324. pi. 43. 1830. Panicum berchtholdium Doell in Mart. Fl. Bras. 2, pt. 2: 150. 1877. Figure 19. Dry hills, open grassland, roadsides, and in cultivated places, 500-2,300 meters; Chiquimula; Jalapa; Santa Rosa; Guatemala; Sacatepe"quez; Quiche"; Quezaltenango; San Marcos. Mexico; El Salvador; Honduras; Nicaragua; Costa Rica. Perennial; culms tufted, sometimes stoloniferous, 30-50 cm. high; sheaths smooth, pubescent on the collar, the margins ciliate; blades short or elongate, 2-6 mm. wide, firm, flat, pilose on both surfaces, sometimes sparsely so; panicles FIG. 19. Chaetium bromoides, X '/»• 79 80 FIELDIANA: BOTANY, VOLUME 24 5-15 cm. long, 1-2 cm. wide, dense, the branches narrowly ascending or appressed; body of spikelet about 6 mm. long, the callus 3 mm. long, the glumes broad, enclosing the florets, the awns 1.5-2.5 cm. long; fruit 4.5-5 mm. long, minutely roughened, bearing a slender awn 1-2 mm. long. CHLORIS Swartz Spikelets subsessile in two rows on one side of the rachis, with one perfect floret, the rachilla articulate above the glumes, prolonged beyond the fertile floret, and bearing a narrow or club-shaped rudiment composed of one or more reduced sterile lemmas; glumes narrow, 1-nerved (rarely 3-nerved), the second a little longer than the first; fertile lemma 3-nerved, awned from the back just below the usually acute tip, the callus more or less bearded on the sides, the keel glabrous or sparsely pilose, the margins usually ciliate, the hairs on the upper part often much longer than the rest. Annual or perennial, often stoloniferous grasses, with 2-several digitate, verticillate, or subracemose spikes. Species probably about 70, in warmer regions of both hemi- spheres. Florets dark brown. Fertile lemma minutely ciliate or glabrous on the margins C. petraea. Fertile lemma conspicuously long-ciliate on the margins C. ciliata. Florets green or pale, sometimes tinged with purple. Rudiment broad, truncate, usually conspicuous. Plants annual; fertile lemma long-ciliate above, the hairs as much as 4 mm. long, conspicuous; rudiment composed of 1 sterile floret C. virgata. Plants perennial; fertile lemma ciliate, with short inconspicuous hairs; rudi- ment composed of 2 sterile florets, the lower one similar to the fertile. C. gayana. Rudiment narrow, acute, usually inconspicuous. Spikelets 4-5 mm. long. Awn of fertile lemma 10-12 mm. long; spikes relatively stout. . C. rufescens. Awn of fertile lemma 5-6 mm. long; spikes slender C. mollis. Spikelets not more than 3.5 mm. long C. radiata. Chloris ciliata Swartz, Prodr. Veg. Ind. Occ. 25. 1788. Cynodon ciliatus Rasp. Ann. Sci. Nat. 5: 303. 1825. Chloris propinqua Steud. Syn. Gram. 204. 1854. C. ciliata var. texana Vasey, Bull. U. S. Dept. Agr. Bot. 12, no. 1: pi. 30. 1890. C. texana Nash, Bull. Torrey Club 25: 441. 1898. C. nashii A. Heller, Muhlenbergia 5: 120. 1909. Black heavy soil, Corozal and Sibun River, British Honduras. Not known from Guatemala. West Indies; southern Texas; Mexico; Nicaragua; Venezuela; Colombia; Uruguay; Argentina. Perennial; culms tufted, erect, sometimes geniculate at the nodes, 20-75 cm. (usually 30-40 cm.) tall, somewhat flattened, glabrous; sheaths rounded on the SWALLEN: GRASSES OF GUATEMALA 81 back, or flattened and keeled toward the summit, glabrous; ligule very short, sometimes minutely ciliate; blades flat, acuminate, 5-20 cm. long, or longer on the innovations, the uppermost reduced, 3-5 mm. wide, scabrous on the margins, otherwise glabrous; spikes 3-6, 4-8 cm. long, flexuous, digitate, narrowly ascend- ing, silvery, tinged with brown; glumes 1-nerved, the first narrow, acute, 1.3 mm. long, the second broad with hyaline margins, subobtuse, 2 mm. long, mucronate; fertile floret 2-2.5 mm. long, the callus bearded, the lemma acute, conspicuously ciliate on the keel and margins nearly to the apex with long white hairs, the awn about 1 mm. long, scabrous; rudiment club-shaped, composed of two reduced florets, the first about 1.2 mm. long, glabrous, the summit and margins hyaline, the awn 1 mm. long, the second much smaller, awnless. Chloris gayana Kunth, ReV. Gram. 1 : 89. 1829. Rhodes grass; "zacate gordura." Probably escaped from cultivation, "La Aurora," Guatemala. Tropical America; introduced from Africa. Perennial; culms densely tufted, commonly 1-1.5 meters tall, compressed, frequently with strong arching stolons; sheaths glabrous or scaberulous, the lower ones compressed-keeled, the upper rounded on the back, sometimes with a tuft of long hairs at the mouth; ligule membranaceous, very short, ciliate with long hairs; blades flat, usually elongate, tapering to a fine point, 3-7 mm. wide, scabrous, especially on the margins; spikes 6-20, 5-12 cm. long, narrowly ascending in a rather dense head; spikelets 4.5 mm. long; glumes acute, 1-nerved, or the second sometimes 3-nerved, scabrous on the keel, the first 1.5 mm. long, the second 2.5 mm. long, mucronate; fertile floret 3.5 mm. long, the callus bearded, the lemma acute, short-ciliate on the margins, the hairs longer on the upper third, the awn 4-6 mm. long, scabrous; rudiment composed of two reduced florets, the first similar to the fertile floret, 2.5 mm. long, glabrous, the awn 2-4 mm. long, the second small, club-shaped, awnless. Chloris mollis (Nees) Swallen, N. Amer. Fl. 17: 596. 1939. Gymnopogon mollis Nees, Agrost. Bras. 427. 1829. G. rupestre Ridley, Jour. Linn. Soc. 27: 73. 1890. Chloris leptanatha Hitchc. in Urban, Symb. Ant. 7: 166. 1912. C. rupestris Hitchc. Misc. Pub. U. S. Dept. Agr. 243: 126. 1936. In shade of cactus thickets, dry slopes along Rio Motagua, west of Teculutan, Dept. Zacapa, 250 meters, Steyermark 29192. West Indies; Colombia; Venezuela; Ecuador; Peru. Annual; culms tufted, erect, or geniculate at the lower nodes, 20 cm. to more than a meter tall; sheaths rounded on the back or keeled only near the summit, glabrous or sparsely pubescent, the margins finely papillose-ciliate; ligule 0.5 mm. long, minutely ciliate; blades flat, acuminate, scabrous, 5-15 cm. long, 1-6 mm. wide; spikes 5-15 (rarely fewer), 5-12 cm. long, slender, somewhat flexuous, ascending or appressed, aggregate on an axis as much as 5 cm. long; spikelets very narrow; glumes acuminate, awn-pointed, 1-nerved, scabrous on the keel, the first 3-4 mm. long, the second 4-5 mm. long; fertile floret 4-5 mm. long, the callus bearded on the sides, the lemma shortly ciliate on the margins toward 82 FIELD IANA: BOTANY, VOLUME 24 the summit, the awn 5-6 mm. long, scabrous; rudiment very narrow, about 2 mm. long, the callus bearded, the margins ciliate near the tip, the awn about 4 mm. long, scabrous. Ghloris petraea Swartz, Prodr. Veg. Ind. Occ. 25. 1788. Eustachys petraea Desv. Nouv. Bull. Soc. Philom. Paris 2: 189. 1810. Schultesia petraea Spreng. PI. Pugill. 2: 17. 1815. Chloris swartzii C. Muell. Bot. Zeit. 19: 341. 1861. C. septentrionalis C. Muell. Bot. Zeit. 19: 340. 1861. C. swartziana Doell in Mart. Fl. Bras. 2(3): 68. 1878. Sands along the coast, British Honduras. Not known from Guatemala. Southeastern United States; eastern Mexico; West Indies; Honduras; Costa Rica; Panama. Perennial; culms erect or sometimes decumbent at the base and rooting at the lower nodes, 30 cm. to more than 1 meter high, conspicuously flattened; sheaths broad, flattened and keeled, crowded at the base in a fan-shaped cluster; ligule very short, minutely ciliate; blades conduplicate at the base, becoming flat toward the obtuse tip, 4-20 cm. (mostly about 10 cm.) long, 4-8 mm. wide, glabrous or densely pubescent on the upper surface at the very base; spikes 2-7 (usually 4-6), 3-12 cm. (mostly 6-8 cm.) long, digitate, narrowly ascending; spikelets 2 mm. long, horizontally spreading; glumes 1-nerved, scabrous on the keel, the first 1.2 mm. long, acute, crescent-shaped, the second a little longer, broader, obtuse, notched, with an awn 0.5-1 mm. long; fertile floret dark-brown, 1.8 mm. long, the callus very short and rounded, the lemma obovate, blunt, pubescent on the keel, sparsely short-hispid on the upper half of the margins, the tip scabrous, the internerves smooth and shining, awnless; rudiment oblong- truncate, about 1 mm. long, 0.5 mm. wide, the tip scabrous. Chloris radiata (L.) Swartz, Prodr. Veg. Ind. Occ. 26. 1788. Agrostis radiata L. Syst. Nat. ed. 10. 2: 873. 1759. C. glaucescens Steud. Syn. PI. Glum. 1: 206. 1854. Gymnopogon radiata Parodi, Physis 4: 180. 1918. Figure 20. Abundant in brushy field between Jutiapa and La Calera, Dept. Jutiapa, about 850 meters. West Indies; Mexico to Paraguay. Annual; culms erect or decumbent at the base, branching, 15-60 cm. high, distinctly flattened; sheaths compressed-keeled, longer than the internodes, glabrous; blades thin, flat, mostly 4-10 cm. long, or the lower ones sometimes longer, smooth or scabrous, sometimes sparsely pilose; ligule 0.5 mm. long, mi- nutely ciliate; spikes 5-15 (mostly more than 10), 4-8 cm. long, slender, straight or flexuous, subdigitate or in two or three approximate fascicles, ascending or spreading; spikelets appressed; glumes acuminate, 1-nerved, the first 1-2 mm. long, the second 2-3 mm. long, glabrous, or scabrous on the keel; fertile floret about 2.5-3 mm. long, narrow, the callus bearded, the lemma glabrous on the back, short-ciliate on the upper part of the margins, the awn 5-10 mm. long, scaber- ulous; rudiment very slender, 1 mm. long, glabrous, the awn 4-6 mm. long, scaberulous. FIG. 20. Chloris radiata, X 83 84 FIELDIANA: BOTANY, VOLUME 24 Chloris rufescens Lag. Var. Cienc. 4: 143. 1805. C. aristata (Cerv.) Swallen, N. Amer. Fl. 17: 596. 1939. Agrostomia aristata Cerv. Naturaleza 1: 345. 1870. Open hillsides in pine-oak forest, along streets and roadsides, open ground and waste places, up to 2,000 meters; Guatemala; Quiche" ; Huehuetenango. Mexico; Costa Rica. Stoloniferous perennial; culms erect or decumbent at the base, 15-75 cm. tall, compressed, sometimes branching at the lower nodes; sheaths compressed-keeled, glabrous or papillose-pilose near the summit, the margins hyaline; ligule mem- branaceous, 0.5 mm. long, minutely ciliate; blades flat from a conduplicate base, 4-20 cm. long, sometimes longer on the innovations, 2-4 mm. wide, scabrous, with a few long hairs on the upper surface near the base; spikes 4-9, 4-10 cm. long, digitate, or sometimes with a single spike a short distance below the others, ascending or somewhat spreading; spikelets 4 mm. long, appressed or somewhat spreading; glumes acuminate, 1-nerved, scabrous on the keel, the first 2.5 mm., the second 4 mm. long; fertile floret 3.6-4 mm. long, the callus bearded, the lemma acute, appressed-ciliate on the margins nearly to the summit, the hairs somewhat longer above, the awn about 0.8 mm. from the tip, 10-12 mm. long, scabrous; rudiment narrowly triangular, truncate, 1.2-2 mm. long, the awn 4-8 mm. long, scabrous. Chloris virgata Swartz, Fl. Ind. Occ. 203. 1797. C. pubescens Lag. Var. Cienc. 4: 143. 1805. Rabdochloa virgata Beauv. Ess. Agrost. 84, 158. 1812. Chloris elegans H.B.K. Nov. Gen. & Sp. 1 : 166. pi. 49. 1816. C. alba Presl, Rel. Haenk. 1: 289. 1830. Agrostomia barbata Cerv. Naturaleza 1: 346. 1870. Figure 21. Fields and waste places, up to 1;500 meters; Izabal; Zacapa; Jutiapa; Santa Rosa; Guatemala. West Indies; central and south- western United States and Mexico to Argentina. Also in the Old World. Annual; culms erect, or usually decumbent at the base, sometimes rooting at the lower nodes, 10 cm. to more than 1 meter high; sheaths compressed-keeled, glabrous, mostly longer than the internodes; ligule very short, minutely ciliate; blades flat, 4-25 cm. long, 3-7 mm. wide, scaberulous or nearly smooth on both surfaces, sometimes more or less papillose-pilose on the upper surface near the base, the margins scabrous; spikes 3-15 (usually about 6), 3-9 cm. (usually 5-6 cm.) long, erect or narrowly ascending, flexuous, crowded in a rather dense silvery head; spikelets 3-3.5 mm. long; glumes acuminate, 1-nerved, scabrous on the keel, the first 1.5-2.5 mm. long, the second 2.5-3 mm. long, with an awn about 1 mm. long; fertile floret 3-3.5 mm. long, the callus bearded, the lemma acute, the keel bowed out at the middle, short-ciliate on the margins on the lower part, long- ciliate on the upper third, the hairs as much as 4 mm. long, the awn rather stout, 6-10 mm. long, scabrous; rudiment 2-2.5 mm. long, about 0.7 mm. wide, subacute, the awn 5-7 mm. long. FIG. 21. Chloris virgata. Plant, X 1A; glumes and florets, X 5. 85 86 FIELDIANA: BOTANY, VOLUME 24 CHUSQUEA Kunth emend. Caespitose or dumetose bamboos with determinate or indeterminate rhizomes or both; culms erect with nodding or more commonly scandent tips, rarely pros- trate, the internodes not hollow, or only exceptionally so (usually by the break- down of the pithy center in senescent culms), cylindrical, sometimes shallowly sulcate for a short distance above the insertion of the branch complement; nodes usually more or less conspicuously inflated. Culm sheaths persistent or promptly deciduous. Branches (sometimes suppressed at the lower nodes of the culm) unarmed, of two categories at each node: a single, strong central one, and numerous shorter, more slender, subequal ones arising independently, from distinct buds; branches of both kinds usually rebranched. Leaf blades typically without, ex- ceptionally with, visibly tessellate venation. Inflorescences determinate, sub- spicate or thyrsoid or paniculate racemes or compound panicles, terminal to leafy or leafless branches; spikelets supplied at the base with two empty glumes, two sterile lemmas and terminated by usually one fertile floret. Lodicules 3; stamens 3, styles usually 2. Fruit a caryopsis. About 90 species, all native to the Western Hemisphere main- land and adjacent islands, from Mexico to Argentina and Chile, with probably the widest altitudinal range of any bamboo genus. Although the culms are generally inferior in strength and other physical properties making for versatile usefulness, those of some species are employed to an important extent in house construction and for basketry in areas of abundant natural stands. Some species yield forage of good quality, which assumes considerable importance locally for grazing horses and fattening cattle. Five described species of this genus — four well-defined and one little-known — have been found in Guatemala. At least one addi- tional, undescribed species is represented by numerous specimens too fragmentary to serve as type material. Flowering material. Leaf blades conspicuously tessellate-veined and hairy on the lower surface. C. lanceolate, . Leaf blades not visibly tessellate-veined. Racemes few-flowered. Subsidiary branches verticillate, more or less completely encircling the culm at each node C. heydei. Subsidiary branches not verticillate, emerging only on one side of the culm at each node C. simpliciflora. Racemes many-flowered. Lemmas long-aristate C. longifolia. Lemmas apiculate C. pittieri. Non-flowering material. Leaf blades conspicuously tessellate-veined and hairy on the lower surface. C. lanceolata. Leaf blades not visibly tessellate-veined. Plant spreading by long, slender, indeterminate rhizomes . . . C. simpliciflora. Plant caespitose. F SW ALLEN: GRASSES OF GUATEMALA 87 Culms scarcely exceeding 1 cm. in diameter C. heydei. Culms commonly exceeding 3 cm. in diameter. Lower nodes of the culm bearing a ring of spine-like roots C. pittieri. Lower nodes of the culm without spine-like roots C. longifolia. Chusquea heydei Hitchc. Proc. Biol. Soc. Washington 40: 80. 1927. An imperfectly known bamboo, apparently characterized by small, relatively blunt-tipped leaves and climbing stems, locally common at 1,400 meters; Jutiapa; Santa Rosa (whence the type). Sterile material from Guatemala, San Marcos, and Sacatep£quez apparently belongs here. "Central culm as much as 5 mm. in diameter; fertile shoots in fascicles on the central culm, slender, 10 to 20 cm. long, the lower part with bladeless sheaths, the upper part with one or two foliage leaves; sheaths glabrous, finely ciliate on the collar and with a few long hairs at the sides of the summit; ligule very short; blades of fertile shoots lanceolate, thin, scaberulous, slightly hispidulous beneath at base, 2 to 5 cm. long, 4 to 8 mm. wide, cuneate but scarcely petiolate at base, acuminate at apex, with 2 more prominent veins on each side of the midrib; panicles ovoid, open, 6 to 8 cm. long, the branches single, spreading, the rachis terete, glabrous, the spikelets on branches of second or third order, all spreading; spikelets elliptic, strongly nerved, glabrous, 8 to 9 mm. long, about 2 mm. wide; glumes rounded, unequal, the second about 1 mm. long; sterile lemmas a little less than half as long as the spikelet, acutish, thin, rather weakly 3-nerved; fertile lemma acute, prominently 9-nerved, the palea a little longer." (Hitchcock, op. cit.) Chusquea lanceolata Hitchc., Phytologia, 1(4): 145. 1935. An erect to subscandent bamboo occurring at elevations of 2,000- 3,300 meters (Steyermark), forming dense thickets (Standley), some- times an element in cypress forests (Skutch) ; Chimaltenango (type) ; El Progreso; Solold; Quezaltenango. The leaf blades have well- defined tessellate venation, a character rare in the genus. Culms erect or subscandent, to 9.2 meters tall and 7.5 cm. in basal diameter (other characteristics of culms and those of the culm sheaths and typical branch complement unknown). Internodes of the vegetative branches hispid just below the nodes with retrorsely appressed stiff hairs which, upon falling, leave the surface aciculate and papillose, the internodes of the flowering branches (in the type) sometimes only scaberulous. Leaf sheaths compressed-keeled, salient- veined, usually strongly ciliate on the margins, the lower ones prominently hispid on the back with appressed or spreading retrorse stiff hairs which, upon falling, leave the surface aciculate and papillose, the upper sheaths dorsally glabrous or nearly so, but usually with the characteristic pubescence near the margins; auricles and oral setae lacking; petiole collar only slightly flared, the apex straight or slightly convex at the middle, the margin glabrous or minutely ciliolate; ligule asymmetrical, about 1 mm. high on one side and about 2 mm. on the other, thin, fragile, fissile, glabrous or nearly so on the back and margin; 88 FIELDIANA: BOTANY, VOLUME 24 petiole very short, scarcely exceeding 2 mm. in length, glabrous or nearly so on both surfaces or retrorsely puberulous basally on the upper surface (somewhat longer and often sparsely pilose on one or both surfaces in the type); leaf blade 4 cm. X 8 mm. to 15 cm. X 2.5 mm., ovate-lanceolate to oblong-lanceolate, acuminate or attenuate-acuminate above, usually broadly rounded rarely cuneate- rounded at the base, strongly cartilaginous and finely antrorse-uncinate on the margins, glabrous on the upper surface, appreciably glaucous and somewhat unevenly strewn on the outer two-thirds of the lower surface with antrorse white hairs; midrib, secondary veins and transverse veinlets pale and prominently salient on the lower surface, all except the midrib (which appears divided above into 2-3 slightly salient, scabrous veins) sunken and dark on the upper surface, where the secondary veins are scarcely distinguishable from the tertiary. Inflorescences paniculate, terminating leafy branches, basally included in the sheath, exserted up to about 17 cm., the main axis hollow, rounded on the unbranched side, sulcate and keeled on the other, tomentose on the flat surface and antrorse scabrous on the keels, branches of all orders weakly pulvinate, secund or subsecund, the main branches appressed or more or less completely spreading, up to 6 cm. distant from each other; sulcate or keeled, antrorsely scabrous, especially on the keels; secondary branches antrorsely scabrous, consist- ing of antrorsely spreading racemose clusters of few-several spikelets much over- lapped; the pedicels very slender, stiff, 1-5 mm. long, scabrous; spikelets up to 9 mm. long, crowded, glossy throughout; empty glumes very thin, subscarious, ovate or oblong, obtuse, keelless and veinless, purplish when fresh, drying dark brown, glabrous on the back and margin, subequal, I: slightly under 1 mm. long, II: slightly over 1 mm. to 1.5 mm. long; sterile lemmas purplish when fresh, drying dark brown, lanceolate, attenuate-acuminate, 3-nerved, strongly keeled, apiculate, or awned, glabrous on the margins and throughout on the back, or more commonly antrorsely scabrous on the midrib and on both sides near the apex, and sparsely ciliate on the margins above, I: about 4 mm. long, II: about 5 mm. long including the awn; lemma lanceolate, acuminate, 7-9-nerved, strongly keeled, apiculate or awned, glabrous throughout on the back, sometimes ciliate on the margins above; palea about as long as the lemma, sometimes exserted 1-2 mm., strongly narrowed, biapiculate and often white penicillate above, broadly sulcate (scarcely keeled) below, more narrowly so or canaliculate above, usually markedly but minutely tomentose within the sulcus toward the tip, sometimes perceptibly so throughout. Empty glumes and sterile lemmas usually tinged with wine throughout, the lemmas sometimes so along the margins when fresh, the color turning dark brown upon drying. (The contents of the palea either rudi- mentary or decayed in the specimens available.) Chusquea longifolia Swallen, Jour. Washington Acad. Sci. 30: 310. 1940. A coarse, caespitose bamboo, with unusually long, narrow leaves, forming dense thickets in wet forest and cloud forest and on shaded slopes at 2,000-3,800 meters; Jalapa; Guatemala; Chimaltenango; Quezaltenango; San Marcos. Southern Mexico (whence the type); Costa Rica; Panama. SW ALLEN: GRASSES OF GUATEMALA 89 Caespitose bamboo with strictly determinate rhizomes and erect or suberect, apically arched culms up to about 15 meters tall and 6.25 cm. in basal diameter; internodes usually shallowly sulcate above the insertion of the branches, glabrous, up to 42 cm. long (XXII); nodes somewhat inflated, the lowest 3-4 with aerial roots, the lowest 1-6 without buds, the rest all gemmiferous. Culm sheaths shorter than the internodes, persistent, disintegrating in place (perfect ones not seen); auricles and oral setae apparently not developed; the ligule (in V) about 1.5 mm. long, strongly arcuate, ciliolate on the margin; sheath blade persistent, broadly triangular, appressed. Branches coarse, the principal one to 2 cm. in diameter, bulbous and rooting spontaneously at the base, the auxiliary ones very numerous, very stiff. Leaf sheath usually prominently costate, with secondary veins of variable prominence, puberulent and glabrescent, or glabrous from the first; auricles and oral setae lacking; petiole collar prominent, flared, glabrous, the apex broadly convex, the margin glabrous; ligule short, usually glabrous on the back, fragile; petiole long, thin, compressed, nerve-striate and glabrous or nearly so on both surfaces, narrowly winged on the margins by the decurrent blade; blade up to 15 cm. X 8 mm. and 20 cm. X 16 mm., narrowly lanceolate to linear- lanceolate, acuminate, attenuate, sometimes subulate above, narrowly cuneate at the base, stiff, flat, cartilaginous and antrorse-scabrous on the margins, scabrous to setose on one or both surfaces, sometimes glabrous or nearly so on both; midrib and secondary nerves (3-4 pairs) pale and salient on the lower surface, scarcely discernible above, the tertiary nerves salient and indistinguishable from the secondary ones on the upper surface, transverse veinlets not visible. Inflorescences stiff, narrow racemes terminating auxiliary leafy branches, exserted up to 27 cm., the axes sulcate and ridged, scabrous, the branches ap- pressed, not apparently pulvinate; spikelets numerous, 12-18 mm. long, over- lapping, appressed or more rarely somewhat spreading; empty glumes ovate, obtuse, stramineous, glabrous, nerveless, I: 0.5 mm. long, II: 1 mm. long; sterile lemmas lanceolate, awned, scabrous above on the back, I: obtuse to acute, 7-9 mm. long, II: acute, about as long as the fertile lemma; fertile lemma up to 16 mm. long (including a 2-4 mm. long awn), scabrous on the back, glossy below, the margins involute; palea as long as the lemma (minus its awn) or a little longer, sulcate above between the weak, approximate, glabrous keels, scarious, white sericeous near the narrow, truncate apex, elsewhere glabrous and glossy, the margins wide, involute; lodicules 3, about 1 mm. long, ovate-lanceolate, obtuse, opaque, ciliate on the upper margins; anthers not seen; ovary fusiform, glabrous, style very short, stigmas 2, 2 mm. long, plumose; mature fruit not seen. In San Marcos, where this bamboo is called canito (Steyermark) the culms supply material for the fabrication of coffee baskets. Chusquea pittieri Hack. Oesterr. Bot. Zeitschr. 53: 153. 1903. An erect or subscandent bamboo characterized by a ring of spine-like roots above each node in the lower one-half to two-thirds of the culm. Forming dense thickets in wooded ravines, sometimes an element in oak forests, occurring at elevations of 1,500-1,800 meters; the culms locally used in making sky rockets; the plant known locally as cana brava (Standley). Guatemala; Solola. Panama; Costa Rica (whence the type). 90 FIELDIANA: BOTANY, VOLUME 24 Caespitose bamboo with erect or suberect, apically pendulous or subscandent culms up to 15-18 meters tall and 7.5 cm. in basal diameter, forming relatively open clumps; internodes glabrous, often lightly pruinose when fresh, the epidermis of the basal ones often wine-colored at first, then green, relatively short (V: 15 X 4.8 cm.; XX: 26 X 3.8 cm.), shallowly sulcate above insertion of branches; nodes somewhat to rather prominently inflated, all gemmiferous or, in large plants, the lowermost 8-10 without buds; culm sheaths deciduous, longer than the internodes, leathery when fresh, papery when dry, irregularly tinted with more or less persistent wine color, strongly ribbed by coarse, salient veins, minutely and mostly retrorsely asperulous throughout and somewhat densely strewn, on the outside between the veins, with basally dark-papillate antrorsely appressed or spreading, transparent, colorless, sharp-pointed, fugaceous hairs, densely antrorse-strigose on the inside near the margins at the apex, sparsely to densely brown-ciliate on the margins above, V: gradually contracted above to a very narrow apex (about 5 mm. wide) (the apex of upper sheaths progressively more narrowly attenuate and elongate, quilled, and ending in a perceptibly thickened callus or swelling at the point of abscission of the sheath blade) ; auricles not devel- oped; oral setae none or minute and fugaceous; ligule very small, scarcely integral, hardly more than a dense, crooked row of uneven, mostly short, very stiff, antrorse bristles; blade (of sheath V) more or less persistent, small, narrowly triangular, less than 10 mm. long, antrorsely appressed, quilled upon drying, fluted and antrorsely scaberulous on the outside, densely dark strigose within, blades of upper sheaths progressively longer and narrower and more promptly deciduous. Pri- mary branches up to 2 meters long, the auxiliary ones up to 30-40 cm. long, mostly branched only basally, with prominent nodes, abscissile at lower nodes; leaf sheaths compressed-keeled near the apex, salient- veined, often minutely papillose or "dewy" between the veins, ciliate on the margins; auricles lacking; oral setae several, crowded, transparent, colorless, glabrous, acute; petiole collar very straight or slightly flared, undulating at the apex, the margin fringed at first with long, transparent, colorless, glabrous, acute bristles like the oral setae, these deciduous, leaving the margin erose or irregularly toothed; ligule about 1 mm. long, thin, fissile, scabrous or subglabrous on the back, irregularly convex at the apex, irregularly dentate on the margin; petiole very short, winged almost to the base by the decurrent edges of the blade, antrorse scabrous or tomentose on the upper surface, glabrous on the lower; leaf blade 3 cm. X 3 mm. to 10 cm. X 10 mm. or 11 cm. X 9 mm., narrowly lanceolate, acuminate above, cuneate at the base, with a thin, cartilaginous, antrorsely spinulose margin, glabrous throughout on the lower surface, or with a tuft of white spreading hairs on one side at the base, sparsely strewn on the upper surface with long, thin, colorless, translucent sharp- pointed, antrorsely appressed or spreading hairs, the midrib and secondary veins pale and salient, the tertiary ones weak on the lower surface, the midrib apparently divided into 2-3 strongly salient very scabrous veins on the upper surface, where the secondary and tertiary veins are sunken and scarcely distinguishable from each other. Inflorescences terminating leafy or at length leafless twigs or branches, more or less drooping or nodding, racemose, up to 10 cm. long, relatively simple, the peduncle up to 8 cm. long, solid, glabrous, exserted about 3 cm., the main axis of the raceme deliquescent by repeated, irregular branching, the branches pulvinate and flattened at the base, glabrous or obscurely scabrous on the keels, the ultimate ones (pedicels) 5-18 mm. long; spikelets up to 13 mm. long, fusiform, overlapping 1 SWALLEN: GRASSES OF GUATEMALA 91 but only moderately crowded; disarticulating above empty glume II, empty glumes very small, scarious, glabrous, subequal, orbicular, obtuse, both usually less than 1 mm. long; sterile lemmas very thin, scarious, sometimes translucent, acute, scabrous-awned, glabrous or nearly so on the back, often ciliolate on the margins, sub equal, about 7-nerved, I: 4-6 mm. long, II: 5-7 mm. long; lemma 9-10 mm. long, somewhat ventricose, acute, apiculate, dorsally glabrous, ciliolate on the margins at the very apex, salient-veined with about 13 veins; palea about as long as the lemma or a little longer, slightly ventricose, glabrous, not salient- veined, obscurely sulcate below and more pronouncedly so toward the apex, bimucronate at the apex; lodicules 1-1.5 mm. long, oval to lanceolate, acute to obtuse, translucent, not prominently veined, ciliate on the margins; anthers linear, about 7 mm. long, the connective not salient above; ovary glabrous (teste Hackel); mature fruit brown, glabrous, the surface finely aciculate-striate, fusi- form, slightly tapered toward the tip, crowned by the bent-over base of the style. Chusquea simpliciflora Munro, Trans. Linn. Soc. 26: 54. pi. II. 1868. Figure 22. A high-climbing or trailing bamboo with slender stems sometimes exceeding 24 meters in length, known from Guatemala by a single collection made by Skutch at an elevation of about 400 meters at Finca Chaila, "Zona Reyna," Quiche". The type is from the Canal Zone. The known range of the species extends from Mexico to Venezuela and Ecuador. Clump open, spreading by slender, indeterminate rhizomes which range widely, both underground and on the surface, the culms slender, weak, depending for support on other vegetation, up to and exceeding 24 meters in length, and up to about 1 cm. in diameter, with a very long, very slender tip; internodes cylindrical, not sulcate above the insertion of the branches, up to 17 cm. long, glabrous in the lower part of the culm, covered with tiny retrorse hooks in the slender, terminal portion of the culm, the nodes more or less distinctly inflated, all gemmiferous, fringed on the sheath scar with a shaggy row of brown hairs. Culm sheaths persistent, papery, shorter than the internodes, narrowly triangular, long-atten- uate above, the lower ones brown-pubescent dorsally, the upper ones glabrous or nearly so; auricles and oral setae not developed; the ligule very small and short, the margin fringed with minute, brown cilia; blade very small, quill-like or thread- like, inrolled, persistent. Branches as in the genus, the principal one at each node usually suppressed in the lower and uppermost parts of the culm, elsewhere often highly developed and reaching the dimensions of the main culm, the subsidiary branches numerous, slender, relatively short, rarely exceeding 20 cm., with prominently inflated nodes. Leaf sheaths salient- veined and compressed-keeled, hirsute throughout or in part and glabrescent, minutely papillose between the nerves, fringed along the upper margins with long cilia; auricles not developed, oral setae absent or few, slender, transparent, colorless, glabrous, appressed; petiole collar strongly flared, thin, irregularly undulate at the apex, the margin glabrous; ligule less than 1 mm. long, puberulent or nearly glabrous on the back, truncate or convex at the apex, the margin irregularly ciliolate or glabrous; petiole very short, winged to the very base by the decurrent blade, thickly cartilaginous on one edge, more or less prominently hispid on both surfaces; leaf blade 2 cm. FIG. 22. Chusquea simpliciflora~M.\mTO. A, branch complement including flowering and sterile branches, ca. X Yi\ B, slender tip of flowering culm, ca. X M- 1, spikelet; 2, floret with lemma removed, enlarged; 3, floret with lemma and palea removed, enlarged; 4, pistil and lodicules, enlarged. From William Munro, Mono- graph of the Bambuseae, Linn. Soc. Trans. 26: pi. 2. 1868. 92 1 SW ALLEN: GRASSES OF GUATEMALA 93 X 4 mm. to 11 cm. X 12 mm., lanceolate, acute or acuminate, apiculate above, more or less asymmetrically cuneate at the base, antrorsely scabrous to the touch on the upper surface, hirsute at the base and somewhat so along the midrib on the lower surface, usually slightly paler on the lower surface, serrulate on both margins, the midrib pale and somewhat salient on both surfaces, sometimes strongly twinned and always antrorse-scabrous on the upper surface, secondary veins two or three on each side of the midrib, visible on the lower surface, not distinguishable from the tertiary veins on the upper surface, transverse veins not apparent. Inflorescences small, open, usually very short, racemes terminating subsid- iary branches, set with usually very small leaf blades, the raceme exserted 1-3 cm., bearing 1-several spikelets, the main axis very slender, striate, glabrous, the pedicels minutely pulvinate at the base, very slender, half-spreading, scaberulous; spikelets lax, pale or greenish stramineous, the empty glumes minute, unequal, obtuse, usually glabrous; sterile lemmas narrowly lanceolate, acuminate, attenuate, thin, papery, with a few prominent veins, costate, sparsely strewn with spreading hairs, or glabrous, I: 5-7 mm., II: 7-8 mm. long; fertile lemma up to 11 mm. long, thin, papery, with a few prominent veins, glabrous, acuminate, attenuate, in- completely surrounding the palea; palea about as long as the lemma or a little longer, thin, papery, keeled by two prominent veins, otherwise weak-veined, somewhat depressed between the keels, narrow, acute, truncate but not apparently bifid at the apex; lodicules 3, minute, hyaline, narrow, lanceolate, ciliolate on the margins, indistinctly nerved; anthers not seen (locules of the anthers apiculate, teste Munro); ovary slender, fusiform, glabrous; style short, glabrous, stigmas 2, plumose; mature fruit glabrous, brown, 3 mm. long and 6 mm. broad, flattened- fusiform, not sulcate. CINNA L. Spikelets 1-flowered, disarticulating below the glumes, falling entire; glumes equal, 1-nerved, about as long as the floret; rachilla forming a stipe below the floret, produced beyond the palea as a minute bristle; lemma similar to the glumes, 3-nerved, bearing a minute awn just below the apex; palea a little shorter than the lemma, apparently 1-keeled. Slender to rather coarse perennials with flat blades and open, loose, drooping panicles. Species 3, one in North America and Eurasia, one in Canada and United States, and one in Mexico to northern South America. Cinna poaeformis (H.B.K.) Scribn. & Merr. U. S. Dept. Agr. Div. Agrost. Bull. 24: 21. 1901. Deyeuxia poaeformis H.B.K. Nov. Gen. & Sp. 1: 146. 1815. Poa subuniflora Kunth, Rev. Gram. 115. 1829. Cinnastrum poaeforme Fourn. Mex. PI. 2: 91. 1886. C. miliaceum Fourn. Mex. PI. 2: 91. 1886. Figure 23. Moist pine slopes, about 3,000 meters, Volcan de Santa Maria, Quezaltenango, Steyermark 34099, 34167. Mexico; Costa Rica; Panama; Colombia; Venezuela; and Peru. FIG. 23. Cinna poaeformis. Inflorescence, X 1; spikelet, X 20. 94 SWALLEN: GRASSES OF GUATEMALA 95 Erect perennial; culms slender to rather coarse, 80 cm. to more than 2 meters high; sheaths glabrous, shorter than the internodes; ligule 5-15 mm. long, thin, lacerate; blades 10-30 cm. long, 5-10 mm. wide, flat, acuminate, glabrous or scaberulous, the margins finely scabrous; panicles 15-40 cm. long, the slender drooping branches in distant verticils, naked in the lower half, some of them often as much as 15 cm. long; spikelets somewhat densely clustered, short-pedicellate, 2.5-2.8 mm. long; glumes usually very scabrous; awn of lemma obscure; rudiment slender, glabrous. COIX L. Monoecious, the staminate and pistillate spikelets in the same inflorescence; staminate spikelets 2-flowered in 2's or 3's at each joint of a slender continuous rachis, 2 sessile, the other pedicellate, sometimes wanting; first glume many- FlG. 24. Coix lacryma-jobi, X 1. 96 FIELDIANA: BOTANY, VOLUME 24 nerved, 2-keeled, the keels broadly winged above the middle, the margins narrow and not much inflexed; pistillate spikelets 3, together enclosed in a very hard white or grayish, bead-like involucre or modified bract, the peduncle of the stam- inate raceme protruding from the orifice at the apex. Annual broad-leaved grasses with numerous inflorescences on long stout peduncles, solitary or fascicled in the upper sheaths. Species about 4, one widely distributed in the tropics. Coix lacryma-jobi L. Sp. PL 972. 1753. Job's tears; Idgrimas de San Pedro; lagrimas de Job. Figure 24. Wet ground along streams at low altitudes; Alta Verapaz; Suchitepe"quez; Retalhuleu; Quezaltenango. Introduced from the Old World. Cultivated for ornament and sometimes as a cereal; found as an escape in moist places throughout tropical America. Culms freely branching 1 meter or more high; blades as much as 50 cm. long, commonly 10-20 cm. at the top of the culms, 2-3.5 cm. wide, rounded or cordate, clasping at the base; staminate part of the inflorescence 2~-4 cm. long, the spikelets 8-10 mm. long; beads or sheathing bracts about 1 cm. long, smooth and shining. CRYPTOCHLOA Swallen Inflorescence small, usually partly hidden in the upper sheaths, each bearing both staminate and pistillate spikelets in no definite arrangement; staminate spikelet: glumes and sterile lemma wanting; lemma and palea acute or acuminate, thin, the lemma 1-nerved; stamens 3; pistillate spikelet: first glume wanting; second glume and sterile lemma acuminate, subequal, 3- or usually 5-nerved, the lateral nerves approximate, finely transversely veined; fertile floret subcylindrical, raised on the enlarged and thickened segment of the rachilla; lemma firm, sub- indurate, smooth and shining, gradually narrowed to the blunt tip, the margins not inrolled; palea as long as the lemma, similar in texture. Low monoecious perennial grasses with broad flat blades usually crowded toward the top of the slender wiry culms. Four species described, in Mexico, Central and South America. Cryptochloa granulifera Swallen, Ann. Mo. Bot. Card. 29: 321. 1942. Pajdn. Wet or dense rocky forests, and dry hillsides, 600-1,400 meters; Quezaltenango; San Marcos. Mexico (Veracruz and Chiapas); Honduras; Ecuador. Culms slender, erect, occasionally somewhat geniculate at the lower nodes, as much as 50 cm. high, pubescent in a line on one side, the nodes retrorsely pubescent, otherwise glabrous; sheaths keeled, glabrous, or pubescent toward the summit, mottled with dark spots; ligule 0.5-2 mm. long, obtuse, pubescent, fused with the auriculate summit of the sheath; blades broadly lanceolate, the upper ' SWALLEN: GRASSES OF GUATEMALA 97 ones 6-7.5 cm. long, 10-13 mm. wide (sometimes 20 mm.), rather gradually narrowed to an acuminate tip, glabrous on both surfaces, the margins scabrous; panicles 2-5 cm. long, contracted, partly enclosed in the upper sheaths; staminate spikelets 4.5-5 mm. long, the lemma acuminate or subattenuate, appearing as if awned; fertile spikelet 11-12 mm. long, the second glume and sterile lemma subequal, acuminate, 5-nerved, finely transversely nerved, granular-roughened; fruit 7-8 mm. long, ivory-white, narrowed at the summit to a blunt tip. CYMBOPOGON Spreng. Spikelets in pairs at each node of the short, paired racemes, those of the lowest pair of one or both racemes alike, sterile, awnless, and similar to the pedicellate spikelets above; sessile fertile spikelets dorsally compressed; first glume flat or grooved, sharply 2-keeled; fertile lemma narrow, awned from between two short lobes, sometimes awnless. Rather coarse perennials with long narrow blades and large, usually drooping, compound inflorescences of aggregate pairs of racemes subtended by spathes. Probably about 60 species in the tropics and warmer parts of the Eastern Hemisphere. Cymbopogon citratus (DC.) Stapf, Kew Bull. Misc. Inf. 1906: 322. 1906. Andropogon citratus DC. Cat. Hort. Monsp. 78. 1813, without description. DC. ex Nees, Allg. Gartenz. 3: 267. 1835. Lemon grass; Te limon; Zacate limdn. Probably commonly cultivated in Guatemala as in most of tropical America, although only two specimens have been seen. Introduced from India or Ceylon. Tea made from the leaves is used for colds, fevers, and various other ailments. This plant is the source of part of the lemon grass oil of commerce. Densely tufted perennial, seldom if ever flowering in American tropics; culms erect in large clumps from short rhizomes, commonly 1-2 meters high with numer- ous leafy sterile shoots; sheaths crowded at the base, elongate, glabrous, the lower ones often of nearly equal length, auriculate, the auricles fused with the margins of the ligule; blades as much as 1 meter long, 5-15 mm. wide, attenuate to a fine point, gradually narrowed to a long, almost petiole-like base, scabrous, especially on the margins, the midrib rather strong toward the base; inflorescence 30-60 cm. long, drooping. CYNODON L. Rich. Spikelets 1-flowered, sessile in two rows on one side of the narrow triangular rachis, the rachilla disarticulating above the glumes, prolonged beyond the spikelet in a naked stipe, sometimes bearing a rudimentary floret; glumes subequal, acuminate, 1-nerved, the first lunate, the second lanceolate; lemma acute, awnless, 3-nerved, pubescent on the nerves; palea narrow, acute, as long as the lemma. 98 FIELDIANA: BOTANY, VOLUME 24 Stoloniferous perennials with short blades and few to several slender digitate spikes. Species 6, one widely distributed in warmer regions around the world. Cynodon dactylon (L.) Pers. Syn. PL 1: 85. 1805. Panicum dactylon L. Sp. PL 58. 1753. Capriola dactylon Kuntze, Rev. Gen. PL 2: 764. 1891. Bermuda grass; Pelo de macho (Izabal). Figure 25. Common in open ground at low altitudes; sometimes planted for lawns; Pet£n; Izabal; Escuintla; Guatemala. British Honduras; common throughout the warmer regions of the world. Rhizomatous, stoloniferous, widely creeping perennial; culms wiry, com- pressed, 10-40 cm. high; sheaths usually overlapping, keeled, glabrous or sparsely pilose at the throat; ligule membranaceous, minutely erose, 0.2-0.3 mm. long; blades flat, 2-20 cm. long (usually 5-10 cm.), 2-4 mm. wide, scabrous, especially on the margins, sometimes sparsely pilose; spikes 4-7, slender, arcuate, 2-7 cm. long; spikelets 2-3 mm. long. DACTYLOGTENIUM Willd. Spikelets 3-5-flowered, compressed, sessile and closely imbricate in two rows on one side of the rather narrow flat rachis; rachilla disarticulating above the first glume and between the florets; glumes broad, unequal, 1-nerved, the second mucronate or short-awned below the tip, deciduous; lemmas broad, keeled, 3-nerved, acuminate or short-awned, the lateral nerves indistinct; palea about as long as the lemma; seed subglobose, ridged, enclosed in a thin pericarp. Annual grasses with flat blades and two to several short thick digitate ascend- ing or spreading spikes, the rachis prolonged beyond the spikelets. Three species in Eastern Hemisphere, one introduced in America. Dactyloctenium aegyptium (L.) Richt. PL Eur. 1: 68. 1890. Cynosurus aegyptius L. Sp. PL 72. 1753-. Eleusine aegyptiaca Desf. Fl. Atlant. 1: 85. 1798. Dactyloctenium mucronatum var. erectum Fourn. Mex. PL 2: 144. 1886. Crowfoot grass. Figure 26. Roadsides, fields, and waste places at low altitudes; Izabal; Zacapa; Escuintla; Retalhuleu. Tropical regions of the Old World; introduced in America. Culms branching, radiate-spreading, rooting at the nodes, the ascending ends mostly 20-40 cm. long; spikes 2-5, 1-3 cm. long, thick, digitate, the rachis pro- duced beyond the spikelets in a stiff point; spikelets pectinate, crowded, about 3 mm. long; first glume 1.5 mm. long, acute, scabrous on the keel; second glume a little longer than the first with an awn 1-2.5 mm. long; lemmas acute or acum- inate, 2.5-3.5 mm. long. FIG. 25. Cynodon dactylon. Plant, X 1A; spikelet and two views of floret, X 5. 99 FIG. 26. Dactyloctenium aegyptium. Plant, X /1>; spikelet, floret and seed, X 5. 100 SW ALLEN: GRASSES OF GUATEMALA 101 DENDROCALAMUS Nees Caespitose bamboos with promptly determinate, thick rhizomes; culms erect or suberect, the tip nodding or broadly arched; the branches (in some species suppressed at the lower nodes of the culm) unarmed, fasciculate, very unequal, the central one at each node strongly dominant and flanked by several pairs of progressively shorter and more slender ones; culm sheaths usually promptly decid- uous; leaf blades without typical tessellate venation, but often with pellucid dots or ridges between the tertiary veins. Inflorescences usually capitate, with pseudo- spikelets congested in dense, more or less spherical aggregates at the nodes of leafy or more commonly leafless branches; spikelets few-flowered, the rachilla short, usually disarticulating except below the first lemma; lodicules usually none; stamens 6, the filaments filiform, free, the style solitary, the stigma usually simple. Fruit a dry, starchy caryopsis, with a thick, separable pericarp. About 30 species have been described, all relatively large, tropical bamboos, mostly from southeastern Asia and adjacent islands. Many are locally important as sources of materials for building and for making articles of daily use. One species has been introduced in Guatemala. Dendrocalamus strictus (Roxb.) Nees, Linnaea 9: 476. 1834. Bambusa (as Bambos) stricta Roxb., PI. Coromandel 58. pi. 80. 1795. Figure 27. In the opinion of Gamble (Ann. Roy. Bot. Gard. Calcutta 7: 79. 1896) this is the most common and most universally used bamboo of India. The species has been introduced repeatedly into the Western Hemisphere through the facilities of the United States Department of Agriculture. It has been cultivated for more than 15 years in Puerto Rico and the Federal Experiment Station at Mayaguez, whence material for trial has been introduced into Guatemala through the facilities of the Institute Agropecuario Nacional. It is being propagated at Chocola, Suchitepe"quez, for distribution. India (whence the type). A densely caespitose bamboo with stiff, usually upright culms, strongly vary- ing in stature, habit and wall thickness according to the conditions of growth, up to 15 meters in height and 7.5 cm. in diameter; internodes relatively short, up to 45 cm. in length, often solid or with a very slender lumen when grown under unfavorable conditions, glabrous, usually more or less strongly pruinose when young, the nodes usually somewhat inflated, the lower ones often fringed at the sheath scar with a ring of shaggy brown hairs. Culm sheaths variable, usually relatively broad, with a gently narrowed apex, glabrous or strewn on the back with appressed or spreading pale or dark, stiff, deciduous hairs, ciliate on the margins; auricles and oral setae usually not developed; ligule straight or arcuate, 1-1.5 mm. high, dentate and ciliolate on the margin; sheath blade appressed to the culm, usually persistent, roughly triangular or ovate-triangular with an 102 FIELDIANA: BOTANY, VOLUME 24 abruptly acuminate, often hard-pointed tip, coarsely strigose on the inner surface, more sparsely strewn on the outer surface with dark, appressed, sharp, gradually deciduous hairs, or glabrous from the first. Branches stiff, wiry, the principal one at the lower nodes often short and curved downward, sometimes very long and variously curved, the secondary branches mostly very slender and numerous. Leaf sheaths nerve-striate, glabrous or hispidulous to asperous, ciliolate on the margins; auricles usually not well developed, oral setae small, more or less crisped, pale, glabrous, deciduous, often lacking entirely; petiole collar often thickish, somewhat flared, the margin usually glabrous; leaf blades up to 25 cm. long and up to 30 mm. broad, linear-lanceolate, acuminate, apiculate, rounded or cuneate at the base, scabrous on the upper surface, usually more or less prominently villous on both surfaces, sometimes almost entirely without hairs in the upper part of the culm, midrib and secondary veins salient on the lower surface, the spaces between the tertiary veins more or less thickly strewn with little transverse ridges or pellucid dots often clearly visible only under a lens by transmitted light. DIECTOMIS H.B.K. Spikelets in pairs at the nodes of a readily disarticulating rachis, the rachis joints and pedicels narrow at the base, gradually widened and thickened to the summit, densely ciliate- villous on the margins; sessile spikelet compressed, the first glume deeply sulcate, 2-keeled, awnless, the second glume with a slender somewhat divergent awn; fertile lemma shorter than the glumes, 3-nerved, awned from between 2 small teeth, the awn once-geniculate, much longer and stouter than those of the glumes; pedicellate spikelet prominent; first glume broad, flat, many-nerved, rather abruptly acute or acuminate, bearing a slender awn from between the slender teeth of the bifid apex; second glume much shorter and nar- rower, acuminate. Erect, branching annuals with solitary racemes somewhat aggregate on the branches from the upper nodes, forming a narrow but rather loose compound inflorescence. Monotypic. Diectomis fastigiata (Swartz) H.B.K. Nov. Gen. & Sp. 1: 193. pi. 64- 1816. Andropogon fastigiatus Swartz, Prodr. Veg. Ind. Occ. 26. 1788. Figure 28. Thickets, marshy prairies, and hillsides, to 1,500 meters; Alta Verapaz; Izabal; Zacapa; Chiquimula; Jalapa; Jutiapa; Guatemala. West Indies; Mexico to Brazil. Tropics of the Old World. Slender annual; culms erect, commonly 0.5-1.5 meters, sometimes as little as 15 cm. high, glabrous; sheaths rounded, glabrous, shorter than the internodes; ligule 5-10 mm., rarely 20 mm. long, acuminate; blades elongate, attenuate, flat or involute, 1-4 mm. wide, scabrous; flowering branches from the upper nodes, ascending, forming a narrow, compound but rather loose inflorescence, the ultimate branchlets somewhat flexuous; racemes 2-6 cm. long, partly enclosed in the spathes; sessile spikelet 5 mm. long, the divergent awn of the second glume about 10 mm. long, that of the fertile lemma 4-5 cm. long, once-geniculate, tightly twisted below the bend; pedicellate spikelet conspicuous, 8 mm. long, minutely FIG. 27. Dendrocalamus strictus (Roxb.) Nees. 1, leaf-branch, X 1A; 2, part of flower-panicle, X H; 3, culm-sheath, reduced to about J4; 4, spikelet, enlarged; 5, flowering glume, enlarged; 6, palea, enlarged; 7, anther, enlarged; 8, ovary and style, enlarged; 9 and 10, caryopsis, enlarged; 11, leaf-sheath, enlarged. From J. S. Gamble, Bambuseae or British India, Calcutta Botanic Garden, Annals 7: pi. 68. 1907. 103 FIG. 28. Diectomis fastigiata, X 104 SW ALLEN: GRASSES OF GUATEMALA 105 ciliate on the margins, the awns 6-10 mm. long; second glume much narrower, 5 mm. long, acuminate. DIGITARIA Heist. Spikelets solitary, in pairs, or in groups of 4 or 5, alternate in two rows on one side of a 3-angled, winged or wingless raceme, the first glume turned away from the rachis; first glume wanting, or present as a small or minute nerveless scale; second glume much shorter to as long as the spikelet; sterile lemma as long as or slightly longer than the fruit, 5-nerved, the lateral nerves sometimes approximate near the margin; fruit cartilaginous, pale or dark brown, the hyaline margins of the lemma not inrolled. Annuals or perennials with usually flat blades and slender racemes, digitate or racemose on the common axis. Probably more than 300 species in temperate and tropical regions throughout the world. Plants annual; culms decumbent-spreading, or if erect, freely branching at the base. Culms widely spreading, usually rooting at the lower nodes; first glume pres- ent. Spikelets 3 mm. long, the sterile lemma usually conspicuously villous on the margins; rachis 1 mm. wide, without scattered long white hairs. D. sanguinalis. Spikelets 2 mm. long, the sterile lemma subglabrous or inconspicuously pilose; rachis about 0.4 mm. wide with a few scattered long white hairs. D. horizontalis. Culms erect in small tufts; first glume wanting. Spikelets 2 mm. long, villous with golden hairs D. argillacea. Spikelets 1.2-1.8 mm. long, the pubescence white. Racemes 8-25; spikelets 1.2 mm. long D. multiflora. Racemes not more than 8; spikelets 1.5-1.8 mm. long. Racemes 3-6, mostly less than 6 cm. long D. panicea. Racemes 6-8, mostly more than 10 cm. long D. cayoensis. Plants perennial. Plants stoloniferous; foliage densely velvety D. leucites. Plants not stoloniferous; foliage glabrous or sparsely pilose D. obtusa. Digitaria argillacea (Hitchc. & Chase) Fernald, Rhodora 22: 104. 1920. Syntherisma argillacea Hitchc. & Chase, Contr. U. S. Nat. Herb. 18: 296. 1917. Brushy slopes and open ground, up to 1,600 meters; Zacapa; Sacatepe*quez; Guatemala. Mexico; Nicaragua; Costa Rica; Pan- ama; West Indies. Annual; culms 5-35 cm. high, in small dense tufts, erect or somewhat gen- iculate at the base, rather freely branching from the lower nodes; leaves almost 106 FIELDIANA: BOTANY, VOLUME 24 all crowded toward the base; sheaths keeled at least toward the summit, short but longer than the short internodes, or the uppermost elongate; ligule truncate, less than 1 mm. long; blades 2-7 cm. long, 2-3.5 mm. wide, flat, acuminate, sparsely to rather densely pilose or hirsute; racemes 1-4, 1-5 cm. long, stiffly ascending, racemose on a short axis, the rachis wingless; spikelets 2 mm. long, usually in pairs, unequally pedicellate; first glume obsolete; second glume and sterile lemma nearly equal, about as long as the fruit, villous with golden hairs which extend in a tuft beyond the tip of the spikelet. Digitaria cayoensis Swallen, Jour. Washington Acad. Sci. 28: 8. 1938. Soil pockets in stream bed, Mountain Pine Ridge, El Cayo District, British Honduras (type Lundell 6670). Mexico (Yucatan, Gaumer 2494) . Annual; culms erect or ascending, sometimes geniculate and rooting at the lower nodes, freely branching, as much as 80 cm. tall, glabrous; sheaths longer than the internodes, rounded, or keeled only toward the summit, densely hirsute, or the uppermost nearly glabrous, the hairs ascending or spreading; blades flat, acuminate, as much as 16 cm. long, 3-5 mm. wide, scabrous, the upper surface very sparsely pilose; axis of inflorescence 5-8 cm. long; racemes slender, ascending, 8-12 cm. long, pilose in the axils, the rachis 0.3 mm. wide, the very narrow margins scabrous; spikelets 1.5-1.6 mm. long, in groups of three, the unequal pedicels flattened, scabrous, 1-3 mm. long; first glume nearly obsolete; second glume about 1.3 mm. long, acute, 3-nerved, with dense lines of white hairs on the internerves and margins, the hairs near the tip somewhat longer than the others, extending slightly beyond the glume; sterile lemma a little longer than the fruit, 3-nerved, densely pubescent in lines on the internerves and margins, the hairs shorter than those on the second glume; fruit 1.4-1.5 mm. long, dark brown, striate. Digitaria horizontalis Willd. Enum. PL 92. 1809. Milium digitatum Swartz, Prodr. Veg. Ind. Occ. 24. 1788. Panicum horizon- tale Meyer, Prim. Fl. Esseq. 54. 1818. Syntherisma digitata Hitchc. Contr. U. S. Nat. Herb. 12: 142. 1908. Digitaria digitata Urban, Symb. Antill. 8: 24. 1920. Not D. digitata Buese, 1854. A common weed in cultivated ground and waste places, Pete*n; Alta Verapaz; Izabal; Retalhuleu. British Honduras. Tropics of both hemispheres. Similar in habit, size, and pubescence to D. sanguinalis, the blades usually more densely pilose; racemes slender, racemose on a short axis rather than digitate, the rachis 0.4 mm. wide, very narrowly winged, with a few scattered, spreading, long white hairs; spikelets 2 mm. long; first glume minute or wanting; second glume about half as long as the fruit, sparsely villous at the tip; sterile lemma subglabrous or sparsely pilose or villous on the margins, the hairs short. Digitaria leucites (Trin.) Henr. Med. Rijks Herb. Leiden 61: 6. 1930. Panicum leucites Trin. Gram. Pan. 85. 1826. Milium SW ALLEN: GRASSES OF GUATEMALA 107 velutinum DC. Cat. Hort. Monsp. 126. 1813. Syntherisma velutinum Chase, Proc. Biol. Soc. Washington 19: 191. 1906. Digitaria velutina Hitchc. op. cit., 40: 84. 1927. Not D. velutina Beauv. Ess. Agrost. 51, 1812, based on Phalaris velutina Forskal, Fl. Aegypt. Arab. 17, 1775. Figure 29. Dry open banks, roadsides, and open ground, Jalapa; Guatemala; Sacatepe"quez; Huehuetenango. Southern Mexico. FIG. 29. Digitaria kucites, X 1. Stoloniferous perennial; culms erect or ascending, 20-80 cm. high; sheaths mostly longer than the internodes, densely villous, velvety; ligule membranaceous, mostly 3-4 mm. long; blades 5-9 cm. long, 3-4 mm. wide, densely villous; panicle long-exserted, with 4-10 slender ascending racemes; spikelets 2.5-3 mm. long, paired, the pairs approximate or somewhat distant; first glume minute, hyaline, nerveless; second glume and sterile lemma equal, as long as the fruit, densely villous, at least between the lateral nerves; fruit pointed, pale or purple-tinged. Digitaria multiflora Swallen, Jour. Washington Acad. Sci. 28: 7. 1938. Known only from the type, collected in pine-oak uplands, San Agustin, Mountain Pine Ridge, El Cayo District, British Honduras, Lundell 6730. 108 FIELDIANA: BOTANY, VOLUME 24 Annual; culms slender, erect, simple or sparingly branched, 50-115 cm. tall, glabrous; sheaths longer than the internodes, keeled, glabrous, the margins more or less pilose or ciliate toward the base; ligule membranaceous, brownish, 2-3 mm. long; blades flat, acuminate, 10-28 cm. long, 4-8 mm. wide, smooth or scaberulous on both surfaces, sparsely papillose-hirsute on the upper at least toward the base, the margins scabrous; axis of the inflorescence 8-15 cm. long; racemes 8-25, 6-15 cm. long, slender, ascending or sometimes spreading, rather evenly scattered along the axis, the rachis wingless, 0.3 mm. wide, the margins scabrous; spikelets 1.2 mm. long, in groups of 3 or 4, the unequal pedicels terete, glabrous or sparsely scabrous, 1-4 mm. long, somewhat spreading; first glume obsolete or nearly so; second glume 1 mm. long, acute, narrower than the fruit, 3-nerved, with dense lines of white pubescence on the internerves; sterile lemma a little shorter than the fruit, acute, 3-nerved, pubescent like the second glume but the hairs shorter, sometimes nearly wanting on the internerves; fruit 1.1 mm. long, extending slightly beyond the second glume and sterile lemma, acute, dark brown, striate. Digitaria obtusa Swallen, Phytologia 4, no. 7: 425. 1953. Coban, Department Alta Verapaz, Turckheim 3793 (type) . Perennial; culms erect, geniculate at the lower nodes, about 50 cm. high; sheaths about as long as the internodes, glabrous, or the lower ones sparsely pilose on the margins; blades 9-13 cm. long, 3-4 mm. wide, flat, acuminate, glabrous, or sparsely pilose toward the base; racemes 5, 8-10 cm. long, stiffly ascending, spikelet-bearing to the base, pilose in the axils; spikelets mostly in 3's, crowded, 2.2 mm. long; first glume wanting; second glume and sterile lemma sparsely to rather densely pilose between the nerves with capitate hairs, the glume obtuse, 3-nerved, one-half to two-thirds as long as the fruit, the lemma 5-nerved, equaling the fruit; fruit acute, dark brown, striate. This species has been referred to Digitaria villosa (Walt.) Muhl., which differs in having the racemes naked or nearly so at the base, less crowded spikelets, and longer, acute second glume. Several specimens from southern Mexico also may be referable to this species. Digitaria panicea (Swartz) Urban, Symb. Antill. 8: 23. 1920. Milium paniceum Swartz, Prodr. Veg. Ind. Occ. 24. 1788. Sandy fields and along ditches, 1,500-1,600 meters. Sacate- pe"quez; Guatemala. Cuba; Jamaica; Hispaniola. Annual; culms erect or ascending, 15-70 cm. high; sheaths glabrous or sparsely pilose toward the summit; blades 3-11 cm. long, rarely longer, 3-4 mm. wide, acuminate, glabrous or nearly so; racemes 3-6, 2-10 cm. long, ascending to spreading; spikelets 1.5-1.8 mm. long, ovate-elliptic; second glume and sterile lemma subequal, or the glume one-third shorter, appressed-pilose on the margins or nearly glabrous; fruit dark brown at maturity, striate. Digitaria sanguinalis (L.) Scop. Fl. Cam. ed. 2. 1: 52. 1772. Panicum sanguinale L. Sp. PL 57. 1753. Paspalum sanguinale Lam. FIG. 30. Digitaria sanguinalis. Plant, X floret, X 10. 't two views of spikelet, and 109 110 FIELDIANA: BOTANY, VOLUME 24 Tabl. Encycl. 1: 176. 1791. Panicum adscendens H.B.K. Nov. Gen. & Sp. 1: 97. 1815. Digitaria marginata Link, Enum. PI. 1: 102. 1821. D. fimbriata Link, Hort. Berol. 1: 226. 1827. Figure 30. A common weed in cultivated ground and waste places, in warm temperate and tropical regions around the world. Decumbent or geniculate-spreading annual; culms commonly rooting at the lower nodes, ascending, 15 cm. to more than 1 meter long; sheaths shorter than the internodes, sparsely to rather densely papillose-hirsute; ligule membranaceous, truncate, 1-2 mm. long; blades 2-10 cm. long, or sometimes longer in robust specimens, 2-9 mm. wide, scabrous, sparsely to rather densely pilose or papillose- pilose, with prominent white midnerve and margins; racemes 2-several, digitate or with a second whorl a short distance below, the rachis about 1 mm. wide, narrowly winged; spikelets 3 mm. long, the first glume small but plainly evident; second glume acuminate, about three-fourths as long as the fruit; sterile lemma slightly longer than the fruit, nearly glabrous to prominently villous on the margins. DISTICHLIS Raf. Dioecious perennials with creeping, scaly rhizomes, rigid culms, and dense narrow panicles; glumes broad, acute, keeled, 3-7-nerved, the nerves usually faint; lemmas closely imbricate, acute or subacute, faintly 9-11-nerved, the pistil- late coriaceous, much firmer than the staminate; palea shorter to longer than the lemma, the margins bowed out below, the keels minutely ciliate, sometimes winged. Species about 6, North and South America. Distichlis spicata (L.) Greene, Bull. California Acad. Sci. 2: 415. 1887. Uniola spicata L. Sp. PL 71. 1753. Briza spicata Lam. Encycl. 1: 465. 1785. Figure 31. Gracie Rock, Sibun River, British Honduras, Gentle 1623. Not known from Guatemala. Seashores and salt marshes near the coast; British Columbia; Nova Scotia; United States; Mexico (Tamaulipas, Yucatan, and Quintana Roo); Cuba; western coast of South America. Perennial; culms stiffly erect from scaly rhizomes, mostly 10-50 cm. high; leaves numerous, the sheaths much longer than the relatively short internodes, glabrous, the blades conspicuously distichous, stiffly spreading, flat or becoming involute, commonly 3-10 cm. long; panicles dense, narrow, 1-6 cm. long; spikelets usually pale, 5-9-flowered, distinctly flattened; lemmas 3-6 mm. long, acute, glabrous; palea narrowly winged, entire. A sterile specimen, collected on moist salt flats between Mita and Asuncion Mita, 650 meters, Jutiapa, Steyermark 31780, may be Distichlis stricta (Torr.) Rydb. FIG. 31. Distichlis spicata. Plant, X 1; floret, X 5. Ill 112 FIELDIANA: BOTANY, VOLUME 24 ECHINOCHLOA Beauv. Spikelets subsessile, solitary or in pairs in two rows on one side of a slender rachis, scabrous and sparsely to prominently hispid; first glume broad, triangular, acute, 3-nerved; second glume and sterile lemma nearly equal, 5-nerved, the lateral nerves approximate, mucronate, or the glume short-awned, the lemma long-awned or mucronate, sometimes enclosing a palea and staminate flower; fruit plano-convex, elliptic, minutely crested, indurate, shining, minutely striate, the margins of the lemma not inrolled, £he tip of the palea not enclosed. Slender to coarse annuals or perennials with compressed sheaths, linear blades, and few to many densely flowered racemes, distant or approximate on a main axis. Species about 20, in warm regions of both hemispheres. Ligule a dense line of long yellowish hairs; plants perennial. Nodes densely bearded; awns 2-10 mm. long E. spectabilis. Nodes glabrous; awn 3-6 cm. long E. holciformis. Ligule wanting; plants annual. Spikelets 3 mm. long, strongly hispid, the sterile lemma with an awn 1-10 mm. long; culms coarse, erect or decumbent at the base E. cruspavonis. Spikelets 2 mm. long, scabrous, sparsely and inconspicuously hispid, the second glume and sterile lemma mucronate only; culms slender, prostrate- spreading E. colonum. Echinochloa colonum (L.) Link, Hort. Berol. 2: 209. 1833. Panicum colonum L. Syst. Nat. ed. 10. 2: 870. 1759. Milium colonum Moench, Meth. PL 202. 1794. Oplismenus colonum H.B.K. Nov. Gen. & Sp. 1: 108. 1815. Panicum zonale Guss. Fl. Sic. Prodr. 1: 62. 1827. Figure 32. Sand bars and moist ground, usually in waste places at low altitudes; Izabal; Zacapa. Warmer regions of both hemispheres; introduced in America. Annual; culms slender, prostrate to erect, freely branching at the base and lower nodes, 15-70 cm. long; sheaths glabrous; ligule wanting; blades soft and rather thin, lax, 5-10 cm., rarely 15 cm., long, 3-6 mm., rarely 10 mm., wide, glabrous, the margins sparsely scabrous; inflorescence 3-10 cm. long, rarely longer; racemes few to several, ascending, the lower ones 1-2 cm. distant, 1-3 cm. long; spikelets about 2 mm. long, scabrous or finely hispid; first glume tri- angular, acute, about one-third as long as the spikelet; second glume and sterile lemma equal, pointed, awnless; fruit 1.8 mm. long, elliptic, acute. Echinochloa cruspavonis (H.B.K.) Schult. Mant. 2: 269. 1824. Oplismenus cruspavonis H.B.K. Nov. Gen. & Sp. 1: 108. 1815. Panicum sabulicola Nees, Agrost. Bras. 258. 1829. P. cruspavonis Nees, Agrost. Bras. 259. 1829. Oplismenus jamaicensis Kunth, Enum. PI. 1: 147. 1833. Panicum crusgalli var. sabulicola Doell in SW ALLEN: GRASSES OF GUATEMALA 113 Mart. Fl. Bras. 2(2): 142. 1877. Oplismenus angustifolius Fourn. Mex. PI. 2: 40. 1886. Echinochloa sabulicola Hitchc. Contr. U. S. Nat. Herb. 17: 257. 1913. E. crusgalli cruspavonis Hitchc. Contr. U. S. Nat. Herb. 22: 148. 1920. Cola de ardilla; cana morada. Figure 33. FIG. 32. Echinochloa colonum, X 1. FIG. 33. Echinochloa cruspavonis, X 1. Ditches and lake margins, up to 1,500 meters; Alta Verapaz; Izabal; Chiquimula; Jutiapa; Guatemala. West Indies; southern United States and Mexico to Bolivia and Argentina. Warmer regions of both hemispheres. Annual; culms soft and somewhat succulent but rather coarse, erect or de- cumbent at the base, compressed, glabrous, shiny, 0.5-1.5 meters high; lower sheaths longer, the upper shorter than the internodes, compressed, keeled, rather loose, glabrous; ligule wanting; blades elongate, acuminate, 5-15 mm. wide, the margins scabrous; panicles 10-20 cm. long, nodding, the branches densely flowered, the lower ones rather distant, the upper ones crowded, ascending or appressed; spikelets 3 mm. long, rather narrow, sparsely hispid on the nerves, hispidulous between the nerves; first glume broad, triangular, acute; second glume and sterile lemma equal, as long as or a little shorter than the fruit, 5-7-nerved, the glume acuminate or short-awned, the lemma with an awn 1-10 mm. long, some- 114 FIELD IANA: BOTANY, VOLUME 24 times with a palea about as long as the lemma; fruit elliptic, smooth and shining, abruptly acuminate-pointed. Echinochloa holciformis (H.B.K.) Chase, Proc. Biol. Soc. Washington 24: 155. 1911. Oplismenus holciformis H.B.K. Nov. Gen. & Sp. 1: 107. 1815. Berchloldia holciformis Fourn. Mex. PL 2: 41. 1886. Ditches and moist places, usually in shallow water, about 1,500 meters; Santa Rosa; Guatemala. Mexico. Perennial; culms succulent, erect, or decumbent at the base, as much as 2 meters high; sheaths glabrous, smooth; ligule a dense line of stiff hairs; blades as much as 45 cm. long, 2.2 cm. wide, or much less in small plants, scabrous on the margins; panicles 15-40 cm. long, dense, nodding; racemes usually ascending, the rachis scabrous and sparsely hispid with long hairs; spikelets 5-7 mm. long, densely hispid with short appressed hairs; awns 3-6 cm. long, very scabrous. Echinochloa spectabilis (Nees) Link, Hort. Berol. 2: 209. 1833. Panicum spectabile Nees in Trin. Gram. Pan. 138. 1826. Swamps and river margins, British Honduras (El Cayo District) . Not known from Guatemala. Panama; West Indies; Colombia to Surinam, Peru, Brazil, and northern Argentina. Coarse aquatic perennial; culms 1-2 meters tall from a long, creeping, rooting base, the nodes usually densely bearded with yellowish hairs; sheaths glabrous to papillose-hispid, the margins papillose-hispid-ciliate; ligule a dense line of stiff yellowish hairs about 4 mm. long; blades elongate, acuminate to attenuate, 1-3 cm. wide, the margins very scabrous, sparsely papillose or ciliate at the base; inflores- cence 10-30 cm. long, erect, dense, the axis very scabrous and sparsely hispid; racemes usually crowded, 3-6 cm. long, ascending to spreading, the rachis hispid, especially at the base; spikelets about 5 mm. long, very short-pediceled, coarsely hispid; first glume broad, acute or short-awned, two-thirds to three-fourths as long as the spikelet; second glume acuminate; sterile lemma containing a stamina te flower, the awn 2-10 mm. long; fruit 4-5 mm. long including a pointed beak about 0.5 mm. long. ECHINOLAENA Desv. Spikelets in pairs in two rows along one side of a flat rachis, the pairs apparent- ly placed edgewise to the rachis, one of each pair often abortive; glumes broad, firm, acuminate, the first much longer than the second, prominently papillose- hispid, at least on the midnerve; sterile lemma broad, enclosing a nearly equal sterile palea and sometimes a staminate flower; fruit indurate, the margins of the lemma flat or inrolled only at the summit, minutely winged on both sides at the base. Decumbent-spreading grasses with firm flat blades and solitary, divergent racemes. Two species in Central and South America. SWALLEN: GRASSES OF GUATEMALA 115 Echinolaena gracilis Swallen, Jour. Washington Acad. Sci. 23: 457. 1933. Open marshy prairie near Los Amates, Department Izabal, Weatherwax 1601, type. Colombia; Venezuela. Culms very slender, wiry, branching, 75-90 cm. long, appressed-pilose; sheaths of the main culm much shorter than the internodes, papillose-hispid, the margins ciliate; blades as much as 3.8 cm. long, 5 mm. wide, some of those on the secondary branches much reduced, flat, firm, pubescent or pilose above, glabrous beneath, the margins white-cartilaginous, more or less papillose-ciliate toward the base; ligule hairy, not more than 1 mm. long, sometimes scarcely evident; racemes somewhat exserted, not more than 1.8 cm. long, the rachis terminating in a spikelet; spikelets 8-11 mm. long; first glume 8-11 mm. long, that of the terminal spikelet much longer than the others, acuminate, strongly nerved, tuberculate or tuberculate-hispid, the margins ciliate; second glume 6 mm. long, acute, papillose-hispid at the summit; sterile lemma 5 mm. long, similar to the second glume, enclosing a well-developed palea; fruit 3.5 mm. long, smooth, shining. ELEUSINE Gaertn. Spikelets few to several-flowered, compressed, sessile in two rows on one side of a rather broad rachis; rachilla disarticulating above the glumes and between the florets; glumes shorter than the first floret, unequal, the first 1-nerved, the second 3-5-nerved, the lateral nerves approximate, close to the keel; lemmas acute, 3-nerved, the nerves close together, the uppermost somewhat reduced; seed dark brown, roughened by fine ridges, loosely enclosed in the thin pericarp. Annual grasses with two to several racemes digitate at the summit of the culms, sometimes with one or two a short distance below. Species about 6, one in South America, the others in the Eastern Hemisphere, one introduced in America. Eleusine indica (L.) Gaertn. Fruct. & Sem. 1: 8. 1788. Cyno- surus indicus L. Sp. PI. 72. 1753. Eleusine gracilis Salisb. Prodr. Stirp. 19. 1796. E. domingensis Sieber ex Schult. Mant. 2: 323. 1824. Not E. domingensis Pers., 1805. Cynodon indicus Raspail, Ann. Sci. Nat. Bot. 5: 303. 1825. Eleusine stabra Fourn. ex Hemsl. Biol. Centr. Amer. Bot. 3: 565. 1885, name only; Fourn. Mex. PI. 2: 145. 1886. E. indica var. major Fourn. Mex. PI. 2: 145. 1886. Figure 34. A common weed, roadsides, fields, and waste places, up to 1,000 meters; Pet£n; Alta Verapaz; Izabal; Santa Rosa; Escuintla; Guatemala; Huehuetenango. Warm regions of both hemispheres. Culms in tough spreading clumps, somewhat decumbent at the base, 15-70 cm. or rarely as much as 1 meter high, compressed, very smooth, sheaths com- pressed, sharply keeled, sparsely papillose near the margins toward the summit, otherwise glabrous, the margins hyaline; ligule membranceous, erose, about 116 FIELDIANA: BOTANY, VOLUME 24 1 mm. long; blades as much as 25 cm. long, 2-8 mm. wide, flat or conduplicate, the tip navicular, glabrous or sparsely pilose on the upper surface, the margins scabrous; spikes 2-several, 5-10 cm. long, stiffly ascending; spikelets 5mm. long; lemmas 3 mm. long, broad at the base, rather abruptly narrowed to the subacute apex, sometimes mucronate. ELYONURUS Humb. & Bonpl. Spikelets in pairs, alike in size and shape, at the nodes of a tardily disarticulat- ing rachis, one sessile, perfect, the other pedicellate, staminate, the rachis joints and pedicels thickened, densely villous; glumes rather firm, rounded on the back, sharply keeled, acuminate, entire or bifid, the margins inflexed, clasping the second glume; second glume acuminate; sterile lemma hyaline, narrow, nearly as long as the glumes; fertile lemma hyaline, awnless, the palea obsolete. Tufted erect perennials with narrow or involute blades and solitary, terminal, often woolly racemes. Species about 15, in warmer regions of both hemispheres. Elyonurus tripsacoides var. ciliaris (H.B.K.) Hack, in DC. Monog. Phan. 6: 333. 1889. E. ciliaris H.B.K. Nov. Gen. & Sp. 1: 193. 1816. Prairies, rocky hillsides, meadows, and roadsides, 1,000-1,600 meters; Jutiapa; Guatemala; Sacatepe"quez; Huehuetenango. Mex- ico; Panama; Colombia and Venezuela. Perennial; culms densely tufted, erect, 60-100 cm. high, glabrous, sometimes with a pubescent line down one side; sheaths shorter than the internodes, rounded, glabrous, or papillose-pilose or villous toward the summit; ligule membranaceous, minutely ciliate, less than 0.5 mm. long; blades elongate, 1-3 mm. wide, flat or folded, usually villous on the upper surface at the base, the margins scabrous; raceme 5-12 cm. long, the rachis and pedicels densely villous; sessile spikelet 5-8 mm. long; first glume pubescent or villous, the margins densely short-ciliate, winged toward the summit, the tip deeply bilobed, the lobes narrow, acuminate; pedicellate spikelet similar to the sessile but slightly smaller and not as deeply lobed. ERAGROSTIS Host Spikelets few- to many-flowered, the rachilla disarticulating above the glumes and between the florets, or continuous, the lemmas deciduous, the paleas persistent; glumes acute or acuminate, 1-nerved, or the second rarely 3-nerved, much shorter than the spikelet; lemmas acute or acuminate, keeled or rounded on the back, 3-nerved, the nerves prominent or sometimes obscure; palea 2-nerved, often ciliate on the keels. Annuals or perennials with open or contracted panicles of small or rather large spikelets. Species about 200, in temperate and tropical regions of the world. FIG. 34. Eleusine indica. Plant, X H; spikelet, floret, and seed, X 5. 117 118 FIELDIANA: BOTANY, VOLUME 24 Plants annual. Palea prominently ciliate on the keels. Low delicate grasses. Panicles open, loosely flowered, the branches spreading E. amabilis. Panicles dense or spikelike. Culms and panicles conspicuously viscid, the panicle branches stiffly ascending or spreading E. viscosa. Culms and panicles not viscid, the panicles spikelike, the branches appressed E. ciliaris. Palea not prominently ciliate on the keels. Culms creeping, freely branching, forming dense soft mats E. hypnoides. Culms erect or ascending, not forming mats. Panicles long, narrow, dense; spikelets pale, 2-3 mm. long, the lemmas thin, about 1 mm. long E. glomerata. Panicles open; spikelets usually more than 3 mm. long, the lemmas firm. Plants with glandular depressions on the keel of the lemmas or the keel of the sheaths. Spikelets 2.5 mm. wide; glands prominent on the keel of the lemmas. E. cilianensis. Spikelets 1.5 mm. wide; keel of the sheaths with numerous glands. E. glandulosa. Plants not glandular. Spikelets pale, tinged with red or reddish brown (see also E. mexicana), subsessile, fascicled on the branches. Lemmas 2-2.5 mm. long, abruptly acute; spikelets mostly 6-10 mm. long E. maypurensis. Lemmas 5 mm. long, gradually narrowed from the base; spikelets 10-30 mm. long E. simpliciflora. Spikelets grayish-green, pedicellate in open panicles. Spikelets and branchlets appressed along the primary panicle branches E. diffusa. Spikelets and branches usually spreading. Plants delicate; spikelets grayish-green, about 1 mm. wide. E. tephrosanthos. Plants coarser, usually more than 25 cm. high; spikelets reddish, 1.5 mm. wide E. mexicana. Plants perennial. Spikelets, at least the lateral ones, subsessile or short-pedicellate, usually crowded on the branches. Spikelets 1.5 mm. wide, scarcely crowded E. bahiensis. Spikelets 1 mm. wide, crowded. Culms 15-60 cm. high, slender; spikelets 4-5 mm. long, 6-12-flowered. E. acutiflora. Culms 1-2 meters high, relatively stout; spikelets 5-10 mm. long, 10-16- flowered E. domingensis. Spikelets long-pedicellate, usually spreading, in open, diffuse panicles. SW ALLEN: GRASSES OF GUATEMALA 119 Lemmas keeled, the nerves prominent E. elliottii. Lemmas rounded on the back, the nerves obscure. Lateral pedicels usually shorter than the spikelets; panicles relatively narrow, elongate, much longer than wide; sheaths villous, at least toward the summit. Blades as much as 40 cm. long, becoming involute at least in the upper part E. hirta. Blades 15-25 cm. long, flat E. praetermissa. Lateral pedicels much longer than the spikelets; panicles diffuse, some- times nearly as broad as long; sheaths glabrous or more or less pilose or hirsute. Spikelets about 1 mm. wide; lemmas 1.3-1.5 mm. long. Panicles fragile. E. lugens. Spikelets about 1.5 mm. wide; lemmas 1.8-2 mm. long. Blades 1-4 mm. wide; culms 40-80 cm. high E. intermedia. Blades 5-10 mm. wide; culms usually more than 1 meter high. E. hirsuta. Eragrostis acutiflora (H.B.K.) Nees, Agrost. Bras. 501. 1829. Poa acutiflora H.B.K. Nov. Gen. & Sp. 1: 161. 1816. Fields and pinelands at lower altitudes; Pete*n; Jutiapa. British Honduras; Mexico; Honduras; Colombia and Venezuela to Bolivia and Brazil. Perennial; culms tufted, erect, 15-60 cm. high; sheaths glabrous, more or less hairy in the throat, mostly shorter than the internodes; blades rather firm, mostly 5-20 cm. long, 2-4 mm. wide, glabrous or sparsely pilose; panicles 8-30 cm. long, the branches stiffly ascending to spreading, the lower ones sometimes as much as 10 cm. long, pilose in the axils; spikelets 4-5 mm. long, 6-12-flowered, rarely more, short-pedicellate, usually crowded, appressed; lemma about 2 mm. long, acute or subacuminate, scabrous on the keel near the summit. Eragrostis amabilis (L.) Wight & Arn. ex Nees in Hook. & Am. Bot. Beechey Voy. 251. 1838. Poa amabilis L. Sp. PL 68. 1753. P. plumosa Retz. Obs. Bot. 4: 20. 1786. Eragrostis plumosa Link. Hort. Berol. 1: 192. 1827. Pastures and waste places at low altitudes; Izabal; Escuintla; Retalhuleu. British Honduras. A common weed in warmer regions of the world. Annual; culms slender, erect or geniculate-spreading, 10-40 cm. high; blades flat, 4-10 cm. long, 2-4 mm. wide, acuminate, glabrous; sheaths glabrous, with a prominent tuft of hairs at the throat; panicles oblong, 3-12 cm. long, 1.5-3 cm. wide, the short branches stiffly ascending or spreading, 1-2.5 cm. long; spike- lets mostly 1.5-2 mm. long, 4-6-flowered; lemmas 1 mm. long, obtuse, the palea conspicuously ciliate, the hairs about 0.3 mm. long. FIG. 35. Eragrostis cilianensis. Plant, X 1; spikelet, X 5; floret, X 10. 120 SW ALLEN: GRASSES OF GUATEMALA 121 Eragrostis bahiensis Schrad. in Schult. Mantissa 2: 318. 1824. Wet or boggy meadows, 900-1,800 meters, Huehuetenango. Brazil. Perennial; culms erect, commonly 30-70 cm. high, glabrous; sheaths rounded, longer or usually shorter than the internodes, glabrous, or somewhat hairy on the collar; blades firm, mostly 6-12 cm. long, 2-4 mm. wide, tapering to a rather fine point, pilose on the upper surface near the base; panicles 10-15 cm. long, the few branches stiffly ascending, floriferous to the base or nearly so, the branchlets appressed; spikelets 4-7 mm. long, short-pedicellate, appressed; glumes subequal, about 2 mm. long, acute, the second sometimes 3-nerved; lemmas 2 mm. long, ovate, acute, rather abruptly narrowed about the middle. Eragrostis cilianensis (All.) Link ex Vign. Malpighia 18: 386. 1904. Poa cilianensis All. Fl. Pedem. 2: 246. 1785. Eragrostis major Host, Icon. Gram. Austr. 4: 14. pi. 24- 1809. E. megastachya Link, Hort. Berol. 1: 187. 1827. Figure 35. Sand bars and waste places; Izabal; Zacapa; Santa Rosa; Retal- huleu. Southern Canada to Argentina. Introduced from Europe. Annual; culms commonly 15-60 cm. tall, or in dwarf plants as little as 1 cm., erect or geniculate-ascending, branching; sheaths keeled, more or less pilose at the mouth, with rather prominent glandular depressions on the keel; blades usually 3-15 cm. long, 2-7 mm. wide, acuminate, glabrous, with prominent glandular papillae on the margins; panicles 3-15 cm. long, rather dense, the branches stiffly ascending or spreading, spikelet bearing to the base; spikelets oblong, 5-15 mm. long, 2.5-3 mm. wide, 10-40-flowered, short-pedicellate, usually divergent; glumes 2 mm. long, acute; lemmas obtuse or subacute, about 2.5 mm. long, the keel scabrous and bearing a few prominent glands. Eragrostis ciliaris (L.) R. Br. in Tuckey, Narr. Exp. Congo App. 478. 1818. Poa ciliaris L. Syst. Nat. ed. 10. 2: 875. 1759. Fields and waste places, to about 1,500 meters; Pete"n; Izabal; Zacapa; Santa Rosa; Escuintla; Guatemala; Retalhuleu; Quezal- tenango. Common in warm and tropical regions of both hemi- spheres. Figure 36. Annual; culms slender, branching, erect to decumbent-spreading, 10-40 cm. or rarely as much as 60 cm. high; sheaths glabrous or sparsely papillose-pilose, with a tuft of long hairs at the throat; blades flat, acuminate or attenuate, 4-10 cm. long, 2-4 mm., rarely 5 mm., wide, glabrous or sparsely pilose with long hairs; panicles dense, spikelike, interrupted toward the base, 5-12 cm. long; spikelets 2-3 mm. long, 6-10-flowered, nearly sessile; lemmas 1 mm. long; palea conspicuously ciliate on the keels, the hairs about 0.5 mm. long. Eragrostis diffusa Buckl. Proc. Acad. Nat. Sci. Phila. 1862: 97. 1862. E. purshii var. diffusa Vasey, Contr. U. S. Nat. Herb. 1:59. 1890. 122 FIELDIANA: BOTANY, VOLUME 24 Moist fields, about 200 meters; Zacapa. Southwestern United States; Mexico. Annual; culms erect or ascending, sparingly branching, mostly 30-50 cm. high; sheaths glabrous with prominent tufts of hairs at the throat; blades com- monly 5-10 cm. long, 1-3 mm. wide, attenuate, flat; panicles 5-20 cm. long, the relatively short spreading branches densely flowered, the secondary branches FIG. 36. Eragrostis riliaris. Plant, X K; spikelet, X 5; floret, X 10. SW ALLEN: GRASSES OF GUATEMALA 123 appressed; spikelets linear, 5-8 mm. long, often longer than the pedicels; lemmas acute, the nerves evident, the lower ones about 2 mm. long. Eragrostis domingensis (Pers.) Steud. Syn. PL Glum. 1: 278. 1854. Poa domingensis Pers. Syn. PI. 1: 88. 1805. Eragrostis maxima Fourn. Mex. PI. 2: 114. 1886. Common on sand dunes near San Jose", Escuintla, Standley 63965. British Honduras; Mexico (Oaxaca, Yucatan, Chiapas) to Colombia; West Indies. Perennial; culms relatively stout, erect, mostly 1-2 meters high, frequently with a few branches from the middle nodes; sheaths firm, usually longer than the internodes; blades firm, flat, elongate, attenuate, as much as 7 mm. wide, smooth beneath, scabrous on the upper surface and on the margins; panicle narrow, dense, elongate, the branches ascending or appressed, floriferous to the base; spikelets 5-10 mm. long, 10-16-flowered, appressed, the pedicels much shorter than the spikelets; glumes acute, about 1 mm. long; lemmas 1.8-2 mm. long, acute, palea nearly as long as the lemma. Eragrostis elliottii S. Wats. Proc. Amer. Acad. Sci. 25: 140. 1890. Poa nitida Ell. Bot. S. C. & Ga. 1: 162. 1816. Eragrostis nitida Chapm. Fl. South. U. S. 564. 1860. Not Eragrostis nitida Link, Hort. Berol. 1: 193. 1827. Moist or swampy places in pine forests. British Honduras; southeastern United States; eastern Mexico; West Indies. Perennial; culms tufted, erect, 30-80 cm. high; sheaths longer than the internodes, glabrous, with a tuft of hairs at the mouth; blades elongate, attenuate, flat, 1-4 mm. wide, scabrous on the upper surface; panicles usually more than half the height of the culms, the fragile branches stiffly ascending to spreading, few-flowered; spikelets mostly 4-7 mm. long, on long, capillary, spreading pedicels; lemmas 2 mm. long, ovate, abruptly acute, closely imbricate. Eragrostis glandulosa Harvey, Bull. Torrey Club 81:406. 1954. Damp thickets, 1,400-1,700 meters; Jalapa; Sacatepe"quez. Mexico (Guerrero and Jalisco). Annual; culms erect or ascending, 60 cm. to as much as 2 meters high, sparingly branching; sheaths mostly longer than the internodes, compressed, keeled, papil- lose-ciliate, with conspicuous tufts of hairs at the throat, the keel with numerous glandular depressions; blades as much as 50 cm. long, 6-14 mm. wide, scabrous on the upper surface, smooth or nearly so beneath; panicles 25-40 cm. long, the scabrous branches stiffly ascending to spreading, the lower ones as much as 15 cm. long; spikelets 2-8-flowered, 2-5 mm. long, 1-2 mm. wide, green, tinged with purple; glumes narrow, acute or acuminate; lemmas ovate, acute, the nerves obscure, the lowest about 1.8 mm. long. Eragrostis glomerata (Walt.) L. H. Dewey, Contr. U. S. Nat. Herb. 2: 543. 1894. Poa glomerata Walt. Fl. Carol. 80. 1788. P. 124 FIELDIANA: BOTANY, VOLUME 24 conferta Ell. Bot. S. C. & Ga. 1: 158. 1816. Eragrostis conferta Trin. Mem. Acad. St. P4tersb. VI. Math. Phys. Nat. 1: 409. 1830. Figure 37. Common on recently formed sand bar along Montagua River near ruins of Quirigua, Dept. Izabal. Southeastern United States; Mexico; El Salvador; Honduras; Colombia and Venezuela to Bolivia and Argentina. Coarse annual; culms erect, 10 cm. to as much as 1 meter high, rarely more, hard and somewhat woody, usually freely branching; sheaths about as long as the internodes, loose, keeled, glabrous; blades flat, elongate, attenuate, 3-8 mm. wide; panicles 5-50 cm. long, narrow, the short branches narrowly ascending or ap- pressed, densely flowered to the base; spikelets short-pedicellate, 6-8-flowered, 2-3 mm. long, the glumes minute; lemmas thin, about 1 mm. long. Eragrostis hirsuta (Michx.) Nees, Agrost. Bras. 508. 1829. Poa hirsuta Michx. Fl. Bor. Amer. 1: 68. 1803. Locally abundant in sandy pine-oak uplands, San Agustin, Mountain Pine Ridge, El Cayo District, British Honduras, Lundell 6738. Southeastern United States; Mexico (Tamaulipas). Perennial; culms erect, tufted, as much as 120 cm. high; sheaths longer than the internodes, hirsute to glabrous, pilose at the throat; blades elongate, attenuate, scabrous, 5-10 mm. wide; panicles usually more than half the height of the plant, diffuse, the branches rather stiffly ascending to spreading, pilose in the axils with long hairs; spikelets 2-6-flowered, the pedicels usually long and somewhat flex- uous; glumes 1.5-2 mm. long, acuminate; lemmas 2 mm. long, acute, the nerves obscure. Eragrostis hirta Fourn. Mex. PI. 2: 115. 1886. Rocky slopes, about 1,900 meters; Sacatepe"quez; Chimalten- ango; Huehuetenango. Mexico; Honduras. Perennial; culms tufted, erect, 60-100 cm. high; sheaths longer than the internodes, the lower ones sometimes elongate, rather densely villous at least toward the summit; blades as much as 40 cm. long, 2-5 mm. wide, scabrous and sparsely papillose-pilose on the upper surface; panicles 30-45 cm. long, the branches usually narrowly ascending, pilose in the axils; spikelets 4-8-flowered, 3-5 mm. long; glumes subequal, acute, 1.6-1.8 mm. long; lemmas ovate, acute, about 2 mm. long, the nerves obscure or the lateral ones evident. Eragrostis hypnoides (Lam.) B.S.P. Prel. Cat. N. Y. 69. 1888. Poa hypnoides Lam. Tabl. Encycl. 1: 185. 1791. Megastachya hypnoides Beauv. Ess. Agrost. 74, 167, 175. 1812. Poa replans var. caespitosa Torr. Fl. North, and Mid. U. S. 1: 115. 1823. Neeragrostis hypnoides Bush, St. Louis Acad. Sci. Trans. 13: 180. 1903. Ero- sion hypnoides Lunell, Amer. Midi. Nat. 4: 221. 1915. Figure 38. FIG. 37. Eragrostis glomerata. Panicle, about X 1A; spikelet and floret, X 12. 125 126 FIELDIANA: BOTANY, VOLUME 24 Sandy river banks, lake shores, moist ground along ditches and, trails at low altitudes; Pete"n; Alta Verapaz; Izabal; Zacapa. British Honduras; West Indies; United States; Mexico to Bolivia, Argentina, and Brazil. FIG. 38. Eragrostis hypnoides. Plant, X 1A; floret, X 10. Stoloniferous, widely spreading annual, forming dense mats; culms very slender, 5-10 cm. high; blades 1-2 cm. long, flat or becoming loosely involute, stiffly spreading; panicles pale, dense, subcapitate, 1-2 cm. long, nearly as broad; spikelets 5-12 mm. long, few- to many-flowered, on short stiff pedicels; glumes unequal, the first 1 mm. long, the second 1.5 mm. long, broader than the first; lemmas 1.5-2 mm. long, acute, rather broad at the base with thin margins; anthers 0.2 mm. long. Eragrostis intermedia Hitchc. Jour. Washington Acad. Sci. 23:450. 1933. 5 SW ALLEN: GRASSES OF GUATEMALA 127 Sand flats, dry hills, and rocky slopes, 1,500-2,000 meters; Izabal; Jalapa; Guatemala; Solola; Huehuetenango; Quezaltenango. Southwestern United States; Mexico. Perennial; culms tufted, erect, mostly 40-80 cm. high; sheaths glabrous or the lower sometimes sparsely pilose, conspicuously pilose at the throat; blades as much as 25 cm. long, 1-4 mm. wide, attenuate, more or less pilose on the upper surface toward the base; panicles diffuse, commonly 15-35 cm. long, the branches ascending to spreading, pilose in the axils or rarely glabrous; spikelets 3-8-flowered, 3-10 mm. long, about 1.5 mm. wide, the pedicels longer than the spikelets; glumes rather narrow, acute, 1-1.5 mm. long; lemmas 1.8-2 mm. long, acute, obscurely nerved. Eragrostis lugens Nees, Agrost. Bras. 505. 1829. Prairies and meadows, 1,400-1,800 meters; Guatemala; Huehue- tenango. Florida, Louisiana, and Texas; Mexico; Venezuela to Brazil and Argentina. Perennial; culms in small tufts, erect or ascending, 20-60 cm. high; leaves mostly crowded toward the base, the sheaths glabrous or sparsely pilose, hairy at the throat; blades mostly 5-15 cm. long, sometimes longer, 1-3 mm. wide, tapering to a fine, somewhat flexuous tip; panicles long-exserted, 8-30 cm. long, commonly 15-20 cm., diffuse, the slender branches ascending to spreading; spike- lets 2-4 mm. long, about 1 mm. wide, 3-8-flowered, the pedicels long and capillary, the florets closely imbricate; glumes thin, 0.7-1.2 mm. long; lemmas 1.3-1.5 mm. long, ovate, abruptly acute. Eragrostis maypurensis (H.B.K.) Steud. Syn. PI. Glum. 1: 276. 1854. Poa maypurensis H.B.K. Nov. Gen. & Sp. 1: 161. 1816. Open hillsides, clearings, and waste places, to about 1,000 meters; Izabal; Chiquimula; Guatemala. British Honduras; southern Mexico to Bolivia and Brazil. Annual; culms erect or decumbent at the base, 10-40 cm. or sometimes as much as 65 cm. high; sheaths glabrous, shorter than the internodes; blades flat, attenuate, mostly 6-15 cm. long, rarely longer, 2-4 mm. wide, papillose-pilose, especially on the upper surface, or nearly glabrous; panicles 8-15 cm. long, erect, the somewhat distant solitary branches stiffly ascending, spikelet bearing nearly to the base, densely pilose in the axils; spikelets 6-10 mm. long, 8-28-flowered, short-pedicellate, somewhat spreading, usually tinged with red or purple; glumes acuminate, as long as the lowest floret; lemmas 2-2.5 mm. long, broad at the base, rather abruptly narrowed above the middle to an acute or acuminate tip. Eragrostis mexicana (Hornem.) Link, Hort. Berol. 1: 190. 1827. Poa mexicana Hornem. Hort. Hafn. 2: 953. 1815. Pine and scrub-oak forests, damp thickets, meadows, dry, open or brushy slopes, roadsides and waste places, 900-2,400 meters; Alta Verapaz; Izabal; Jalapa; Jutiapa; Santa Rosa; Escuintla; 128 FIELDIANA: BOTANY, VOLUME 24 Guatemala; Sacatepe'quez; Chimaltenango; Solola; Huehuetenango;' Quezaltenango. Texas to California; Mexico; Honduras; El Sal- vador; Costa Rica; Venezuela; Brazil. Culms erect or geniculate at the lower nodes, 20-45 cm. high, glabrous; sheaths glabrous with a conspicuous tuft of hairs at the throat; blades mostly 5-10 cm. long, 2-3 mm. wide, flat, attenuate; panicles oblong or pyramidal, 5-15 cm. long, loosely flowered, the branches ascending or spreading, the branchlets and pedicels divergent; spikelets oblong, usually purple, 4-6 mm. long, 6-10- flowered; lemmas about 2 mm. long, acute or subobtuse. Eragrostis praetermissa Harvey, Bull. Torrey Club 81: 408. 1954. Known only from the type collection from near Santa Rosa, Baja Verapaz, Turckheim 1292. Perennial; culms tufted, erect, about 70 cm. high; sheaths longer than the internodes, densely villous, especially toward the summit, the hairs on the collar conspicuous; blades 15-25 cm. long, 4-6 mm. wide, firm, scabrous, sparsely papillose-pilose on the upper surface; panicles 40 cm. long, 10-15 cm. wide, the branches stiffly ascending to spreading, the lower ones as much as 12 cm. long, the branchlets and pedicels divergent; spikelets 3-5 mm. long, 4-8-flowered, ovate to lanceolate, the florets slightly spreading; glumes acute, about 2 mm. long; lemmas ovate, acute, the lower one 2-2.2 mm. long, the lateral nerves evident but not conspicuous. This species is credited to Mexico by L. H. Harvey, based on a specimen collected at Jacuaro, Michoacan, A. S. Hitchcock 6956. The specimen, however, is referable to E. intermedia Hitchc. Eragrostis simpliciflora (Presl) Steud. Syn. PI. Glum. 1: 278. 1854. Megastachya simpliciflora Presl, Rel. Haenk. 1: 283. 1830. Moist plains, fields, and roadsides, to about 1,500 meters; Jalapa; Guatemala. Southern Mexico to Panama. Annual; culms tufted, often dense, spreading or prostrate, 10-40 cm. long, rather freely branching at the lower nodes; blades 4-12 cm. long, 2-4 mm. wide, acuminate, pilose on the upper surface; panicles 2-10 cm. long, rather dense, usually purple-tinged, the short stiff branches ascending to spreading, spikelet bearing to the base, often so numerous on the branches that the whole plant appears to be a dense inflorescence; spikelets sessile or nearly so, narrow, 1-3 cm. long, 10-30-flowered, solitary or in groups of 2-4, appressed; lemma 5 mm. long, acuminate, gradually narrowed from the base, the lateral nerves double; palea half as long as the lemma, narrow, lunate. Eragrostis tephrosanthos Schult. Mant. 2: 316. 1824. E. delicatula Trin. M&n. Acad. St. Pdtersb. VI. Sci. Nat. 2: 73. 1836. Moist fields, sand flats, roadsides, and waste places, up to 2,000 meters; Alta Verapaz; Izabal; Zacapa; Jalapa; Escuintla; Huehue- SW ALLEN: GRASSES OF GUATEMALA 129 tenango; Suchitepe"quez; Retalhuleu; Quezaltenango. West Indies; Florida to Texas; Mexico to Panama; Colombia to Surinam and Brazil. Annual; culms slender, erect or geniculate-spreading, 10-30 cm. high; blades lax, flat, acuminate, 4-15 cm. long, 2-4 mm. wide, glabrous; panicles lax, open, 5-12 cm. long, pilose in the axils, the branches spreading, naked at the base, often rather densely flowered; spikelets plumbeous, 4-6 mm. long, 1.5 mm. wide, 6-12- flowered, short-pedicellate, usually somewhat spreading, the first glume 1 mm. long, the second about 1.3 mm. long; lemmas 2 mm. long, subobtuse. Eragrostis viscosa (Retz.) Trin. Me"m. Acad. St. Pe"tersb. VI. Math. Phys. Nat. 1: 397. 1830. Poa viscosa Retz. Obs. Bot. 4: 20. 1786. Eragrostis tenella viscosa Stapf ex Hook. f. Fl. Brit. Ind. 7: 315. 1896. Sandy river banks, gravelly or rocky hills and fields to about 2,000 meters; Izabal; Zacapa; Jutiapa; Santa Rosa; Escuintla; Guatemala; Retalhuleu. Mexico; El Salvador. Introduced from southeastern Asia. Culms 10-50 cm. high, geniculate-ascending, viscid at least below the nodes; sheaths longer or shorter than the internodes, glandular toward the summit, with a few long hairs in the throat; blades 3-12 cm. long, 1-3 mm. wide, rather firm; panicles commonly 5-15 cm. long, 1-2 cm. wide, rather densely flowered, the branches stiffly ascending or spreading, viscid; spikelets 3-4 mm. long, pale or purple; lemma and palea obtuse, the keels of the palea ciliate with long hairs. ERIOCHLOA H.B.K. Spikelets usually in pairs, arranged in two rows on one side of a slender rachis, the back of the fruit turned away from the rachis; first glume united with the thickened first segment of the rachilla, forming a ring-like callus below the second glume; second glume and sterile lemma equal or nearly so, acute or acuminate, 3-nerved; fruit much shorter than the second glume and sterile lemma (in our species), elliptic, awnless or short-awned, minutely striate and cross-wrinkled or papillose-roughened, the margins of the lemma firm, inrolled, rather tightly enclosing the palea. Annuals or perennials with flat blades and terminal inflorescences composed of 2 to many one-sided racemes racemose on a common axis. About 25 species, in warm regions of both hemispheres. Racemes 1 or 2, 1-2 cm. long, densely villous E. distachya. Racemes usually few to several, rarely only 2. Sheaths and blades velvety pubescent. Spikelets 6 mm. long, the pedicels with long dense stiff hairs E. nelsoni. Sheaths and blades not velvety, usually glabrous or scabrous. 130 FIELDIANA: BOTANY, VOLUME 24 Spikelets 6-7 mm. long, the second glume long-acuminate, sometimes aristate; racemes few E. aristata. Spikelets 4 mm. long, the second glume acuminate, never aristate; racemes usually numerous E. punctata. Eriochloa aristata Vasey, Bull. Torrey Club 13: 229. 1886. Margin of waterholes and moist salt flats at low altitudes; Zacapa; Jutiapa. Mexico. Annual; culms erect or ascending, 20-30 cm. high, branching at the lower nodes; sheaths mostly longer than the internodes, glabrous; blades 3-7 cm. long, 2-5 mm. wide, acuminate, glabrous; panicles long-exserted, 4-4.5 cm. long, the axis densely scabrous; racemes 1-1.5 cm. long, appressed; spikelets 6-7 mm. long including the awns; second glume acuminate or aristate, densely villous in the lower half; sterile lemma similar to the second glume but shorter; fruit 2.5 mm. long, striate, minutely pubescent at the summit, bearing a scabrous awn about 1 mm. long. The description applies only to the Guatemala specimens, which are not typical. More adequate material may prove that they are a new species. Eriochloa distachya H.B.K. Nov. Gen. & Sp. 1: 95. pi. 30. 1815. Hills between Cajval and Cahabon, 400 meters, Dept. Alta Verapaz. Costa Rica; Panama; Venezuela and Colombia to Bolivia, Paraguay and Brazil. Low, freely branching perennial; culms 10-40 cm. high, slender, erect or geniculate-ascending, densely pubescent below the inflorescence, the nodes bearded, otherwise glabrous; sheaths glabrous or sparsely pilose, with a small tuft of hairs in the throat; ligule densely ciliate, less than 0.5 mm. long; blades 3-15 cm. long, 2-5 mm. wide, flat, acuminate, erect, glabrous, or sparsely pilose on the upper surface, the margins finely scabrous; inflorescence long-exserted, composed of 1 or 2 divergent, distant, short racemes; racemes 1-2 cm. long, straight or some- what curved, densely villous; spikelets 3 mm. long, pectinate, the pedicels with long hairs at the summit; second glume and sterile lemma bluntly acute, densely villous with appressed hairs; fruit 2.4 mm. long, oblong, blunt, pale, awnless, with a few long hairs at the tip. Eriochloa nelsoni Scribn. & Smith, U. S. Dept. Agr. Div. Agrost. Bull. 4: 12. 1897. Damp thickets and grassy slopes, 420-850 meters; Jutiapa; Chiquimula. Southern Mexico; Nicaragua. Annual; culms erect or usually decumbent-spreading, branching, as much as 1 meter long, densely pilose, especially below the inflorescence; sheaths shorter than the internodes, velvety pubescent; blades 6-20 cm. long, 8-14 mm. wide, or those of the branches smaller, acuminate, velvety pubescent; racemes 2-several, SWALLEN: GRASSES OF GUATEMALA 131 ascending to spreading, the rachis densely pilose, the pedicels of the spikelets densely hairy, the hairs stiff, reaching to more than half the length of the spikelet; spikelets 6-8 mm. long, usually spreading; second glume and sterile lemma subequal, acute, densely pilose to above the middle, the upper part glabrous; fruit 4 mm. long, blunt, awnless, minutely striate. Eriochloa punctata (L.) Desv. ex Hamilt. Prodr. PL Ind. Occ. 5. 1825. Milium punctatum L. Syst. Nat. ed. 10. 2: 872. 1759. Agrostis punctata Lam. Encycl. 1: 58. 1783. Oedipachne punctata Link, Hort. Berol. 1: 51. 1827. Helopus punctatus Nees, Agrost. Bras. 16. 1829. Monachne punctata Nash, Bull. Torrey Club 30: 374. 1903. Brushy slopes, open banks, and cultivated ground, near sea level; Izabal. West Indies; southeastern United States; Mexico to Argentina. Glabrous, rather freely branching perennial; culms erect or ascending from a decumbent base, commonly more .than 1 meter high, densely pilose below the inflorescence; sheaths rounded, usually much shorter than the internodes, the prophylla in those subtending the branches often elongate and conspicuous; ligule densely ciliate, about 0.5 mm. long; blades 15-40 cm. long, 5-15 mm. wide, acuminate, the margins finely scabrous; inflorescence 10-20 cm. long, the axis and the rachis of the narrowly ascending racemes densely pubescent and also pilose; racemes many, ascending or appressed, the lower one 4-5 cm. long; spikelets 4 mm. long; second glume and sterile lemma equal, acuminate, densely pilose on the lower part with appressed white hairs, the upper portion glabrous; fruit about 2 mm. long, the hispidulous awn about 1 mm. long. ERIOCHRYSIS Beauv. Spikelets in pairs, the sessile spikelets perfect, the pedicellate somewhat smaller, pistillate, the rachis finally disarticulating below the spikelets; glumes equal, indurate, densely covered on the margins and on the back toward the summit with golden brown silky hairs; fertile lemma awnless. Tufted perennial grasses with short racemes arranged in a very dense, lobed, brown, silky inflorescence. Species 9, four in America, four in Africa, and one in India. Eriochrysis cayennensis Beauv. Ess. Agrost. 8. pi. 4, f> 11- 1812. Figure 39. Wet fields, ditches, and marshy places, up to 1,350 meters; Pete*n; Alta Verapaz; Izabal; Santa Rosa. British Honduras; southern Mexico; Honduras; Costa Rica; Panama; West Indies; Colombia to Surinam, Bolivia, northern Argentina, and Brazil. Coarse, densely tufted perennial; culms erect, commonly 1.5-2 meters high, the nodes densely bearded, otherwise glabrous; sheaths densely and softly villous, FIG. 39. Eriochrysis cayennensis, X H- 132 SWALLEN: GRASSES OF GUATEMALA 133 especially toward the summit, less so below, elongate, overlapping, or sometimes, especially the upper bladeless sheaths, shorter than the internodes; ligule 12 mm. long, thin, white, truncate; blades villous like the sheaths, 15-40 cm. long, 5-12 mm. wide, flat or folded, firm; panicles golden brown, very dense and spike- like, interrupted below, 8-20 cm. long, 2-3 cm. wide, the branches short, appressed, densely villous in the axils with long hairs; spikelets 2.5-3 mm. long, the first glume glabrous on the back, the tip and margins fringed with brown silky hairs. I EUGHLAENA Schrad. Spikelets unisexual, the staminate in terminal panicles of racemes, the pistil- late in spikes infolded in foliaceous spathes or husks, 2-several enclosed together in the leaf sheaths; staminate spikelets 2-flowered, in pairs on one side of a con- tinuous rachis, one nearly sessile, the other pedicellate; glumes membranaceous, acute; lemma and palea hyaline; pistillate spikelets solitary on opposite sides of the rachis, sunken in cavities, the indurate first glume covering the cavity; second glume membranaceous, the lemma hyaline. Coarse annuals with broad flat blades. Species 2, in Mexico and Central America. Euchlaena mexicana Schrad. Ind. Sem. Hort. Goettingen 1832; Linnaea 8: Litt. 25. 1833. Teosinte. Figure 40. Grassy meadows, llanos around Ipala, 900 meters, Chiquimula, Steyermark 30287; abundant in cornfields, region of El Tablon, 850-900 meters, Jutiapa, Standky 75850, 75910. Mexico. Cultivat- ed for forage in several countries of Central and South America. Culms usually in large clumps, erect or ascending, commonly 2-3 meters high, branching at the base; sheaths glabrous; blades flat, elongate, as much as 8 cm. wide, the upper ones reduced, glabrous on both surfaces, the margins scabrous; staminate racemes few to many, crowded; staminate spikelets about 8 mm. long, acute or acuminate; joints of the pistillate spike about 8 mm. long, readily dis- articulating, bony-indurate, smooth and shining. f FESTUCA L. Spikelets few- to several-flowered, the rachilla disarticulating above the glumes and between the florets; glumes narrow, unequal, the first 1-nerved, the second 3-nerved; lemmas rounded on the back, awnless or awned from the tip; palea not adhering to the caryopsis. Densely tufted annuals or perennials with flat or involute blades and narrow or open panicles. Species about 150, in cold and temperate regions of both hemi- spheres and in tropics at higher altitudes. Plants annual. Lemmas ciliate toward the summit F. megalura. 134 FIELDIANA: BOTANY, VOLUME 24 Lemmas not ciliate F. dertonensis, Plants perennial. Blades flat, 5-10 mm. wide. Lemmas awnless or nearly so F. amphssima. Lemmas awned, the awn 8-13 mm. long F. breviglumis. Blades involute, or if flat, not more than 3 mm. wide. Lemmas very scabrous, the nerves prominent; blades lax, those of the culm flat F. willdinoviana. Lemmas glabrous or scabrous only toward the tip, the nerves obscure; blades firm, involute. Blades very scabrous; spikelets 1-1.5 cm. long, 6-8-flowered. .F. tolucensis. Blades smooth or scaberulous; spikelets 5-8 mm. long, 3-4-flowered. F. hephaestophila. Festuca amplissima Rupr. Bull. Acad. Sci. Brux. 9, pt. 2: 236. 1842; Fourn. Mex. PL 2: 125. 1886. Open woods, 2,000-3,000 meters; Sacatepe"quez; Huehuetenango; Quezaltenango. Mexico; Costa Rica; Panama. Coarse perennial; culms erect, as much as 2 meters high, scabrous or nearly smooth; sheaths scabrous, shorter than the internodes, the lowermost becoming fibrous with age; blades 15-75 cm. long, 5-10 mm. wide, flat, firm, scabrous, acuminate or attenuate to a fine involute tip; ligule very short; panicles 20-30 cm. long, open, the branches slender, more or less flexuous, ascending or spreading, naked at the base, the lower ones usually about 15 cm. long, sometimes as much as 25 cm. long; spikelets 8-15 mm. long, 4-7-flowered; glumes acute or acuminate, the first 4-6 mm. long, 1-3-nerved, the second 5-7 mm. long, 3-nerved; lemmas 7-8 mm. long, acute or acuminate, smooth or somewhat scabrous toward the tip, awnless or mucronate. Festuca breviglumis Swallen, Contr. U. S. Nat. Herb. 29: 398. 1950. Figure 41. Damp forests, region of Los Positos, Dept. Chimaltenango, 2,250-2,400 meters, Standley 80130. Costa Rica, the type from El Copey, Province of San Jose", Standley 41998. Perennial; culms erect, 55 cm. tall; sheaths glabrous, the lowermost becoming fibrous with age; ligule a very short membrane less than 0.1 mm. long; blades flat, attenuate, 5-8 mm. wide, scabrous on the margins, otherwise glabrous; panicles 21 cm. long, lax, drooping, the branches somewhat flexuous, paired, the pairs distant; spikelets mostly 4-flowered, 2 cm. long, excluding the awns; glumes FIG. 40. Euchlaena mexicana. Plant, much reduced; pistillate inflorescence enclosed in bract (a) and with portion of bract removed (b), X 1; lateral view of rachis joint and fertile spikelet (c), and dorsal view of same, showing first glume (d), X 2. 135 136 FIELDIANA: BOTANY, VOLUME 24 acute or subacuminate, the first 3-5 mm. long, 1-nerved, the second 4-9 mm. long, 3-nerved; lowest lemma 14-17 mm. long, attenuate, scabrous, the awn 8-13 mm. long; palea about 1 cm. long, finely scabrous; rachilla appressed- hirsute. Festuca dertonensis (All.) Aschers. & Graebn. Syn. Mitteleur. Fl. 2: 558. 1901. Bromus dertonensis All. Fl. Pedem. 2: 249. 1785. Open banks, dry slopes, and moist meadows, about 2,400-4,000 meters; Chimaltenango; Quezaltenango; San Marcos. British Columbia to Baja California; Ecuador to Chile, Brazil, and Argen- tina. Introduced from Europe. Figure 42. Annual; similar in habit and aspect to F. megalura; panicles usually shorter and more open, the branches sometimes spreading; first glume about 4 mm. long, the second 6-7 mm. long; lemmas 7-8 mm. long, scabrous toward the summit, the margins not ciliate; awn about 1 cm. long. Festuca hephaestophila Nees ex Steud. Syn. PL Glum. 1: 310. 1854. F. tolucensis var. hephaestophila Nees ex Hook. Jour. Bot. Kew Misc. 2: 105. 1850. Summit of Sierra de los Cuchumatanes, ^between Tojquia and Caxin bluff, Dept. Huehuetenango, 3,700 meters, Steyermark 50156, 50177. Southern Mexico. Perennial; culms in dense tufts, erect, 10-50 cm. high, rarely higher; leaves glabrous or scaberulous, the blades firm, involute, curved, as much as 20 cm. long, but usually less; panicles 4-10 cm. long, narrow, the few short branches appressed or sometimes spreading, few-flowered; spikelets 5-8 mm. long, 3-4-flowered; lemmas about 5 mm. long, glabrous on the back, scabrous toward the tip, the nerves obscure, the awn 1-2 mm. long. Festuca megalura Nutt. Jour. Acad. Phila. II. 1: 188. 1848. Vulpia megalura Rydb. Bull. Torrey Club 36: 538. 1909. Openings in pine and pine-oak woods, dry ridges, fields and waste places, 2,000-4,200 meters; Jalapa; Chimaltenango; Quezal- tenango. Western North America from British Columbia to Baja California; Pacific slope of South America. Annual; culms slender, erect, 20-60 cm. high; sheaths and blades soft, glabrous, the blades mostly 1-2 mm. wide; panicles 7-20 cm. long, narrow, rather dense, the branches appressed, spikelets 3-5-flowered, appressed, short pedicellate; glumes very unequal, the first 1-2 mm. long, the second 4-5 mm. long; lemmas 4-6 mm. long, scabrous, tapering into a straight awn 8-15 mm. long. Festuca tolucensis H.B.K. Nov. Gen. & Sp. 1: 153. 1816. Open places in pine forests, 4,100-4,600 meters; San Marcos. Southern Mexico; Costa Rica. FIG. 41. Festuca breviglumis. Spikelet, X 5. 137 FIG. 42. Festuca dertonensis. Plant, X Y