489 
58. Sieglingia. Floral glume cleft to the middle, densely pubescent. 
++ ++ Panicle exserted. 
= Floral glumes 3-nerved, often obscurely so, 
a. Empty glumes ovate, acute, or subacute. 
1. Floral glumes obtuse, often toothed or mucronate (except Sieglingia Wrightii.) 
58. Sieglingia. Floral glumes convex, at least below, usually toothed or mucro- 
nate. 
59. Diplachne. Floral glumes usually keeled and mucronate or toothed at the 
apex: spikelets sessile on the under sides of the branches. 
2, Floral glume ovate, entire, acute or subacute: spikelets compressed, linear, 
60. Eragrostis. Glumes membranaccous: florets less than 3 mm. long, 
53. Scleropogon. Glumes rather thick: florets 5 mm. long or more. 
b. Empty gluines thin, obovate or oblanceolate. 
61. Hatonia. Empty glumes very dissimilar; the upper one broadly obovate. 
62. Koeleria. Empty glumes similar, oblanceolate, 
= = Floral glumes 5 to many-nerved. 
a, Grain free. 
1. Floral glumes thin or membranaceous at the obtuse or subacute apex. 
63. Melica. Upper florets imperfect, unlike tke others, convolute about each 
other. 
67. Poa. Imperfect floret only one: floral glumes 5-nerved, webbed at the base. 
68 Panicularia. Imperfect floret only one: floral glumes7 to 9-nerved, glabrous. 
2, Floral glumes firm or coriaceous, acute, or very narrow at the apex and dentic- 
ulate. 
64. Uniola. Three to six lower glumes empty: spikelets broad, eompressed. 
65. Distichlis. Dicecious: empty glumes only 2: spikelets compressed, in small 
narrow panicles. 
66. Dactylis. Spikelets narrow, densely clustered, in branching panicles. 
b. Grain adnate to the palet. 
69. Festuca. Spikelets less than 1 em. long: floral glumes convex. 
70. Bromus. Spikelets more than | em, long: floral glumes often carinate. 
aa, Spikelets nearly or quite sessile in unilateral racemes, these usually digitate or 
Tacelose, 
Tribe IX. Spikelets 1 to 4-flowered, witha rudiment (except in Spartina), nearly 
or quite sessile in two rows on one side of the continuous axis, forming unilateral 
racemes or spikes, these digitate or racemose.—CHLORIDEX. 
* Spikes digitate or whorled. 
+ Spikes slender. 
40. Capriola. Spikelets awnless: floral glume deeply carinate, 
+ + Spikes thick: florets closely imbricated, 
++ One perfect floret in each spikelet. 
42. Chloris. Floral glume with a short dorsal awn or awnless, 
