POACEAE. 51 



65. BROMUS L. Broom-grass, Chess. 



Flowering glumes compressed-keeled. 



Palet less than 54 as long as the flowering glume. 



Leaves glabrous; glumes glabrous or merely scabrous. 1. B. polyanthus. 

 Leaves pubescent ; glumes hairy at least when young. 2. B. marginatus. 

 Palet more than 54 as long as the glume. 3. B. vnioloides. 



Flowering glumes rounded on the back, at least at the base. 



Flowering glumes oval or broadly elliptic ; second empty glume 5-7-nerved ; 

 first 3-nerved ; introduced annuals. 

 Flowering glumes nearly as broad as long, awnless or with a short, dorsal 

 awn. 4. B. brizaeformis. 



Flowering glumes much longer than broad, always conspicuously awned. 

 Flowering glumes glabrous. 



Sheaths glabrous ; awn much shorter than the flowering glume, nearly 



erect. 5. B. secalinus. 



Sheaths pubescent ; awn fully as long as the glume, at maturity strongly 

 divergent. 6. B. patulus. 



Flowering glumes more or less hairy. 7. B. hordeaceus. 



Flowering glumes lanceolate or oblong-lanceolate ; second empty glume 3- 

 nerved ; first one i-nerved except in B. Porteri. 

 Awns shorter than the glumes ; perennials and all except B. inermis native. 

 Inflorescence more or less drooping. 



First empty glume 3-nerved. 8. B. Porteri. 



First empty glume i -nerved. 



Flowering glumes evenly pubescent on the back ; sheaths densely 



lanate. 9. B. lanatipes. 



Flowering glumes ciliate on the margins, glabrous or sparingly hairy 

 on the back ; sheaths glabrous or the lower sparingly hirsute. 



10. B. Richardsoni. 

 Inflorescence not dropping. 



Inflorescence narrow, its branches erect ; flowering glumes usually 

 awned. 11. B. Pumpellianus. 



Inflorescence broad, its branches spreading ; flowering glumes usually 

 awnless. 12. B. inermis. 



Awn longer than the glumes ; introduced annuals. 



Spikelets numerous on slender, recurved, secund pedicels ; flowering glumes 



8-12 mm. long. 13. B. tectorum. 



Spikelets few; pedicels not secund; flowering glumes 12-16 mm. long. 



14. B. sterilis. 



1. Bromus polyanthus Scribn. In meadows from Mont, to Ore., N. M. 

 and Calif. — Alt. 6000-11,500 ft. — Trimble Springs; hills above Dix P. O. ; 

 Cerro Summit; West Mancos Canon; Rabbit-Ear Pass; Keblar Pass; Robin- 

 son, Summit Co. ; Walsenburg ; Veta Pass ; foot of Mt. Riclitofen, on the 

 Michigan; near Chambers' Lake; Cameron Pass. 



2. Bromus marginatus H. & A. In meadows from Alb. to B. C, Colo, and 

 Calif. — Alt. S000-6000 ft. — Steamboat Springs, Routt Co. ; Ft. Collins ; Fish 

 Creek Falls, Routt Co. 



Bromus marginatus latior Shear is a large variety with large open panicle 

 and longer awns. — ^Vicinity of Boulder. 



3. Bromus unioloides (Willd.) H. B. K. Meadows from Ala. and Calif, 

 to La. and Tex. — Fort Collins; Cherokee Hill. 



4. Bromus brizaeformis F. & M. Locally introduced from Mass. to Wash., 

 Del. and Calif. Native of Europe and Asia. — Alt. 5000-6000 ft. — Vicinity of 

 Boulder. 



