co 
Ti 
COMPARATIVE ANALYSIS. 
. Flowers in unilateral spikes 3 
Flowers not unilateral 6 
. Calyx many-flowered Triticum. 
Calyx one or two-flowered Alas 
. Styles united half way up . Spartina. 
Styles distinct 5 
. Glumes nearly equal Cynodon. 
Glumes very unequal . Digitaria. 
. Spikelets imbedded in the rachis Rottbolia. 
Spikelets not imbedded. ae 
Spikelets two or more from same point 11 
Spikelets solitary 8 
. Spikelets one-flowered Knappia. 
Spikelets more than two-flowered 5) 
. Glume solitary, inclosing the spikelet between it and rachis Lolium. 
Glumes two, their edges towards the rachis. 10 
. Florets equal ; ; : Brachypodium. 
Florets smaller upwards Triticum. 
. Spikelets one-flowered . Hordeum. 
Spikelets two or more flowered Elymus. 
. Calyx one-flowered 13 
Calyx two or more flowered 23 
. Glumes with feathery awns Lagurus. 
Glumes awnless, or awns not feathery 14 
. Panicle dense, (subspiked,) florets mostly ‘cderioonedl 15 
Panicle loose, florets not imbricated 20 
. Corolla with tuft of hair at base Amoplalla. 
Corolla without hairs at base 16 
. Corolla with one or two valves of imperfect florets at bass Phalaris. 
Corolla without valves of imperfect florets at base 17 
. Corolla awnless . Phleum. 
Corolla awned 18 
. Corolla of one valve, the awn asad : : Alopecurus. 
Corolla of two valves, the awn terminal or dorsal 19 
. Glumes awned, awn of corolla terminal Polypogon. 
Glumes awnless, awn of corolla dorsal , .  Gastridium. 
. Fruit inverted with the hardened corolla; corolla awnless 21 
Fruit not inverted with the corolla; corolla often awned 2g 
. Corolla with a small valve at the base Phalaris. 
Corolla without a valve at the base Milium. 
. Corolla with long hairs at base ; : Calamagrostis. 
Corolla without hairs at base Agrostis. 
28. Florets with a pinnated bractea 
Cynosurus. 
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