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. i. 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. E. 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. E. 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. villifloms. 



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

 lets usually singly; flowering glumes glabrous. n. 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. Durarigo; Fort Collins; 

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

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



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

 Colo. Alt. 5000-6000 ft. Idaho Springs; Black Canon; vicinity of Boulder; 

 Fontaine qui Bouille. 



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 Canon, Larimer Co. ; eastern Colorado ; along river, east of Ft. Collins. 



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



