20 
POACEAE. 
3. ANDROPOGON L. Beard-grass, Blue-stem. 
Fourth glume of the sessile spikelet with a long geniculate awn, more or less 
spiral at the base. 
Outer two glumes of the sessile spikelet more or less hispidulous all over; hairs 
on the rachis-internodes usually 2 mm. or less long. 1. A. furcatus. 
Outer two glumes of the sessile spikelet smooth or nearly so, except on the 
nerves ; hairs of the rachis-internodes 3-4 mm. long. 2. A. chrysocomus. 
Fourth glume of the sessile spikelet awnless or with a short, straight, untwisted 
awn. 3. A. Hallii. 
1. Andropogon furcatus Muhl. In meadows from Me. to Sask., Fla. and 
Tex.—Alt. 4000-8000 ft.—Near Boulder; La Veta; Golden; West Dry Creek, 
Larimer Co.; Manitou; Colorado Springs; Tobe Miller’s ranch, near La 
Porte; Ft. Collins. 
2. Andropogon chrysocomus Nash. In dry meadows from Neb. to Colo., 
Kans. and Tex.—Alt. 4000-8000 ft.—La Veta; on the plains. 
3. Andropogon Hallii Hack. In sandy soil from Neb. to Mont., Kans. and 
Mex.—Exact locality not given. 
4. SORGHASTRUM Nash. Indian Grass. 
1. Sorghastrum nutans (L.) Nash. ( Chrysopogon nutans Benth.) In dry 
soil from Ont. to Man., Fla. and Ariz.—Alt. 4000-6000 ft.—Near Boulder; 
New Windsor, Weld Co.; Canon City; Tobe Miller’s ranch, near La Porte; 
Ft. Collins. 
5. SORGHUM Pers. Johnson Grass, Sugar Corn. 
1. Sorghum halapense (L.) Pers. Cultivated for fodder and occasionally 
escaped.—Rocky Ford. 
Tribe 2. ZOYSIEAE. 
6. HILARIA H. B. K. Mesquite, Black Grama. 
Outer glumes of the spikelets cuneate, awnless; the nerves strongly diverging. 
1. H. mutica. 
Outer glumes linear or oblong, awned ; the nerves parallel. 2. H. Jamesii. 
1. Hilaria mutica (Buckl.) Benth. On dry plains from southern Colo, to 
Tex. and Ariz.—Reported from Colorado, but doubtful. 
2. Hilaria Jamesii (Torr.) Benth. Hillsides and gulches of the mesas from 
Wyo. to Nev., Tex. and N. Mex.—Alt. 4000-6000 ft.—Deer Run; mesas near 
Pueblo; Arboles; Mancos; Hotchkiss, Delta Co. 
Tribe 3. PANICEAE. 
7. SYNTHERISMA Walt. Crab-grass. 
Pedicels terete or nearly so, sparingly if at all hispidulous; lower sheath glabrous. 
1. S. humifusum. 
Pedicels sharply 3-angled; the angles strongly hispidulous; as are also the sheaths. 
2. 5 ". sanguinale. 
