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.
GRAMINEAE 1
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 indeterminate 3 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 sheath 1 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 1 A; 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 
