56 POACEAE. 



4. Sitanion brevifolium J. G. Smith. On hills and mountain-sides from 

 Wyo. to Utah, Colo, and Ariz. — Alt. 5000-10,000 ft. — Mancos; Ouray; Mar- 

 shall Pass; vicinity of Boulder; mountains between Sunshine and Ward, 

 Boulder Co.; Twin Lakes; Georgetown; Walsenburg; Colorado Springs; 

 La Veta; vicinity of Ft. Collins; Willow Creek, Routt Co. 



5. Sitanion pubiflorum J. G. Smith. On dry hills from Colo, to Ariz, and 

 N. M.' — Alt. about 6000 ft. — Trinidad. 



69. ELYMUS L. Wild Rye, Lyme-grass. 



Flowering glumes long-awned; empty glumes lanceolate or linear-lanceolate, 

 narrowed at the base. 

 Spike broad ; spikelets spreading. 



Flowering glumes hirsute or villose. 1. E. canadensis. 



Flowering glumes scabrous or strigose-hispidulous or nearly glabrous. 



Robust ; spike usually included at the base ; leaves 8-15 mm. wide. 



2. E. robustus. 

 Slender ; spike exserted ; leaves seldom over 5 mm. wide. 



3. B. brachystachys. 

 Spike narrow ; spikelets erect. 



Leaves 7-15 mm. wide, spreading; empty glumes lanceolate, acuminate to 



short-awned. 4. E. glaucus. 



Leaves less than 5 mm. wide, usually nearly erect; empty glumes very nar- 

 rowly linear-lanceolate, long-awned. 

 Spike 7-8 mm. thick ; awns 30-40 mm. long. 5. E. Saundersii. 



Spike 5 mm. thick or less ; awns 5-10 mm. long. 6. E. Macounii. 



Flowering glumes awnless or short-awned ; empty glumes linear-aristiform or 

 subulate, or if broader not narrowed at the base. 

 Empty glumes aristiform or narrowly subulate. 



Plant stout, 1—2 m. high; spikelets 2-6 at each joint; flowering glumes acute 

 or very short-awned; in our form scabrous-stigulose. 



7. B. condensatus. 

 Plant slender, 3-10 dm. high ; spikelets 1-2 at each joint. 



Flowering glumes broadly lanceolate, acute or minutely awn-pointed, glab- 

 rous ; rachis scabrous on the sharp angle ; spikelets erect. 



8. E. triticoides. 

 Flowering glumes narrowly lanceolate, awned ; rachis nearly terete, strigose ; 



spikelets somewhat spreading. 

 Flowering glumes glabrous. 9. E. ambiguus. 



Flowering glumes strigose. 10. E. strigosus. 



Flowering glumes villous. 12. E. villifforus. 



Empty glumes lanceolate-subulate, tapering from a rather broad base ; spike- 

 lets usually singly ; flowering glumes glabrous. 11. E. simplex. 



1. Elymus canadensis L. On river-banks and among bushes from N. S. 

 and Wash, to Ga. and N. M. — ^Alt. 4000-7000 ft. — Durango ; Fort Collins ; 

 along Platte River, near Denver ; La Porte, Larimer Co. ; Salida, Chaffee 

 Co. ; gulch west of Soldier Caiion ; Black's Lake. 



2. Elymus robustus S. & S. On river-banks from S. D. to Ida., Mo. and 

 Colo. — Alt. S000-6000 ft. — Idaho Springs; Black Caiion; vicinity of Boulder; 

 Fontaine qui Bpuille. 



3. Elymus brachystachys Scribn. & Ball. On dry plains and hills from 

 Mich, and S. D. to Tex., N. M. and Utah; also in Mex.— Alt. 4000-6500 ft. 

 — Rist Caiion, Larimer Co. ; eastern Colorado ; along river, east of Ft. Collins. 



4. Elymus glaucus Buckley. (^Elymus Sihiricus Thurb. ; not L.) In mead- 



