192 
Spikelets in pairs, one perfect, 
the other staminate or neu- 
ter, the branchlets decid- 
Spikelets not in pairs. 
Glumes awned; lemma with a 
long slender terminal awn 71. 
Glumes awnless; lemma with 
a short straight awn be- 
low the apex. .........- 
Spikelets not articulated below 
the glumes. 
Spikelets with several bristles 
below the glumes; lemma 
Spikelets with no bristles below. 
Glumes strongly compressed, 
longer than the lemma; 
inflorescence a dense 
spike-like panicle...... 
Glumes not strongly com- 
pressed. 
Lemma and palea much 
more delicate than the 
glumes, the palea 
shorter than the lemma, 
often wanting........ 
Lemma and palea of about 
the same texture as the 
glumes and as long or 
longer. 
Lemma with a tuft of 
hairs at base, the 
awn dorsal; rachilla 
usually prolonged. . . 
Lemma without a tuft of 
hairs at base or the 
hairs very short. 
Glumes obtuse, equal, 
as long as the lem- 
ma; inflorescence 
elongated, usually 
a narrow or spike- 
like panicle... ... 
Glumes shorter than 
the lemma, often 
unequal. 
Lemmas awned or 
mucronate... .. 
Lemmas awnless. 
Nerves of lemma 
silky-villous. . 
Nerves of lemma 
glabrous... ... 
CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
65. Lycurus (p. 304). 
PotyeoGon (p. 317). 
72, Cinna (p. 317). 
66. PEREILEMA (p. 305). 
67. PHLEUM (p. 306). 
73. AGRostis (p. 318). 
74, CALAMAGROSTIS (p. 321). 
70. EpIcaMPEs (p. 314). 
63. MUHLENBERGIA (p. 286). 
69. BLEPHARONEURON (p. 314). 
68. SPoROBOLUS (p. 306). 
