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. i. 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. z. 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. 



i. 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. 



i. 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. 



i. 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 (Torn) 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. 5". humifusum. 

 Pedicels sharply 3-angled ; the angles strongly hispidulous ; as are also the sheaths. 



2. S. sanguinale. 



