270 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
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9, AVENEAE. 
Articulation below the spikelet. 
Second glume narrowed above; lemma of second floret awned on the back, 
the awn hooked_____.---_--_-_-_--_ 70. Notholcus (p. 371). 
Second glume broadened above; lemmas awnless. 
72. Sphenopholis (p. 372). 
Articulation above the glumes and between the florets. 
Spikelets awnless _----------- 73. Koeleria (p. 372). 
Spikelets awned. 
Awn from between the teeth of the lemma, flat, twisted below. 
75. Danthonia (p. 3872). 
Awn dorsal, terete, straight or twisted. 
Spikelets less than 1 cm, long, erect; panicle dense, spikelike. 
71. Trisetum (p. 371). 
Spikelets more than 1 em. long, drooping._____ 74. Avena (p. 372). 
10. CHLORIDEAE. 
Plants moncecious or dicecious; pistillate spikelets many-awned; staminate 
spikelets awnless; plant stoloniferous_________._____ 87. Opizia (p. 384). 
Plants with perfect spikelets. 
Spike solitary, terminating the culm. 
Spikelets with 1 perfect long-awned floret______ 80. Saugetia (p. 378). 
Spikelets with several perfect short-awned florets. 
82. Tripogon (p. 381). 
Spikes 2 or more on each culm. 
Spikes racemosely arranged. 
Spikelets articulate below the glumes, 1-flowered ; maritime grasses 
with stout rhizomes__ -?7. Spartina (p. 373). 
Spikelets articulate above the glumes, 2 to several-flowered (the 
second floret rudimentary in Bouteloua), 
Spikes short and relatively broad; upper floret often reduced 
to the awns _ --81. Bouteloua (p. 379). 
Spikes long and slender; perfect florets 2 or more. 
Lemmas awnless or with minute awns, the upper floret 
reduced to an awnless small lemma. 
85. Leptochloa (p. 382). 
Lemmas with awns as long as the body, the upper floret 
reduced to a slender awn____86. Gouinia (p. 384). 
Spikes digitate or nearly so. 
Spikelets with 2 or more perfect florets. 
Rachis extending beyond the spikelets. 
84. Dactyloctenium (p. 382). 
Rachis not extending beyond the spikelets. 
83. Eleusine (p. 381). 
Spikelets with 1 perfect floret only. 
Sterile floret wanting; lemma obtuse___'76. Capriola (p. 373). 
Sterile floret present; lemma awned or mucronate. 
Fertile floret raised on a long stipe; sterile florets reduced 
to long awns____-______ 79. Gymnopogon (p. 377). 
Fertile floret not raised on a stipe; sterile florets consist- 
ing of evident lemmas 78. Chloris (p. 374). 
