Kansas Academy of Science. 



Fls. dioecious, staniinate fls. in conspicuous spikes; perennial 34 Buchloe. 



Fls. perfect (or upper imperfect); an annual creeping grass 35 Munroa. 



Fls. monoecious in jointed spikes; upper spikelets staminate sessile; lower 



spikelets pistillate, and imbedded in the thickened cartilaginous rachis... 1 Tripsacum. 

 Flowers not as above (8). 

 Fls. crowded in a dense cylindrical spike (9). 

 Fls. in one-sided spikes or branches of the panicle (19). 



Fls. in simple, racemose, spicate, contracted or more or less spreading pani- 

 cles (34). 



Spike oval, or at most oblong; very dense 10 Phalaris. 



Spike cylindrical (10). 



Spike very dense and cylindrical (11). 



Spike less dense or very loose (12). 



Flowering glume witb a slender dorsal awn 18 Alopecurus. 



Flowering glume destitute of an awn 17 Phleum. 



Several bristles below the articulation of the spikelets 6 Setaria. 



No bristles below tbe articulation of the spikelets (13). 



Outer glumes long-awned, flowering glumes generally awned 20 Polypogon. 



Outer glumes often bristle-pointed, flowering glumes triple-awned 12 Aristida. 



Outer glumes not long-awued, flowering glumes not triple-awned (14). 



Glumes blunt, acute, or pointed, but not awned (15). 



Some of the glumes awned (17). 



Spikelets 3-5-flowered, compressed 42 Koeleria. 



Spikelets 1-flowered, occasionally a rudiment above '16). 



Lower outer glume longer than the flowering glume 22 Agrostis. 



Outer glumes small or nearly as large as the flowering glume 15 Muhlenbergia. 



Spikelets 1-flowered, 6 glumes present, no true palet 11 Anthoxanthum. 



Spikelets 1-flowered, but only 4 glumes present (18). 



Lower outer glume larger than the flowering glume 22 Agrostis. 



Outer glumes small or nearly as large as the flowering glume 15 Muhlenbergia. 



Flowers dioecious, the pistillate in short capitate spikes 31 Buchloe. 



Flowers not as above (20). 



Glumes (or palets) only two, chartaceous, strongly compressed 9 Leersia. 



Glumes (including palets) more than two (21). 



Spikelets with one perfect flower and two empty, hairy, nearly equal outer 

 glumes, with a cup-like or annular swelling of the pedicel just below the 

 spikelet , 4 Eriochloa. 



Spikelets, etc., not as above (22). 



Spikelets with one or more flowers, but only one perfect (23). 

 Spikelets with two or more perfect flowers (31). 



Flowers in indistinctly one-sided spikes or bunches (24). 

 Flowers in strictly one-sided spikes or clusters (27). 



Spikelets solitary at each joint of the slender triangular rachis, and partly 



immersed in an excavation 30 Schedonnardus. 



Spikelets not as above (25). 



Stamen 1, palet only 1-nerved, nearly as long as its glume 21 Cinna. 



Stamens 2 or 3, palet2-keeled or 2-nerved (26). 



Spikelets several-flowered, flowering glumes awnless 33 Leptochloa. 



Spikelets with 1 (or rarely 2) perfect flower and a bristle-like rudiment or 



awn-like pedicel 20 Gymnopogon. 



Spikelets sessile and remotely alternate on long and filiform branches of the 



panicle, flowers awned 29 Gymnopogon. 



Spikelets not as above, flowers awned or awnless (28). 



Flowers awned (29). 



Flowers awnless (30). » 



Spikes digitate or fasciculate at the summit of the culm 28 Chloris. 



Spikes numerous in a racemose panicle, or one terminal; spikelets densely 



crowded 31 Bouteloua. 



