490 
48. Trichloris. Floral glume with 3 terminal awns. 
++ ++ 2 to 5 perfect florets in each spikelet. 
47. Eleusine. Floral glumes ovate, awnless. 
* * Spikes racemose. 
+ Spikelets remotely alternate in the slender spikes. 
44. Gymnopogon. Spikelets awned. 
45. Schedonnardus. Spikelets awnless, appressed in notches in the continuous 
rachis. 
48, Leptochloa. Floral glume short-awned or awnless: spikelets not appressed 
in notches, 
++ Spikelets closely imbricated in rather thick spikes. 
41. Spartina. Spikelets strictly 1-flowered: floral glume acute, awnless. 
46. Bouteloua. Spikelets with an awned rudiment: floral glume 3-toothed or 
3-awned. 
49, Bulbilis. Diccious: the staminate spikelets in pectinate spikes on an elon- 
gated peduncle; the pistillate ones in sessile clusters. 
aaa. Spikelets sessile on opposite sides of a channeled rachis forming solitary ter- 
minal spikes. 
» 
Tribe XI, Spikelets 1 to 10-flowered: empty glumes usually awned or aristiform; 
floral glume awned (sometimes awnless in Lolium).—HORDEX. 
* Spikelets solitary. 
71. Lolium. Spikelets with the edge to the rachis: lower inner empty glume 
wanting. 
72. Agropyron, Spikelets with the side to the rachis: both empty glumes present. 
** Spikelets 2 to5 at each node of the rachis: empty glumes all present, nearly 
side by side in front of the spikelets, 
73. Hordeum. Spikelets 1-flowered, in clusters of 3 each; the lateral spikelets 
slightly stalked, staminate or neutral. 
74 Elymus. Spikelets 2 to 6-flowered in clusters of 2 to 4, all perfect and alike. 
75. Hystrix. Spikelets in very short-pedicelled clusters: empty glumes small 
and deciduous. 
B. Culms woody: leaf blade with a short petiole articulated with the sheath. 
76. Arundinaria. Spikelets many-flowered, compressed. 
1. TRIPSACUM L. 
Spikes single or digitate, staminate above, pistillate below: stam- 
inate spikelets sessile, in pairs, usually secund on the triangular 
jointed rachis; each with one neutral and one staminate floret; the first 
outer glume 2-keeled near the margins, coriaceous or rigid; inner glumes 
membranaceous; pistillate spikelets solitary, imbedded in cavities 
ov alternate sides of the thick cylindrical polished rachis; each with 
one neutral and one pistillate floret; the first empty glume thick and 
polished, closing the mouth of the cavity; inner glume thinner; floral 
glumes and palets thin and scarious; styles united, bearing two brown 
