POACEAE. 51 



65. BROMUS L. Broom-grass, Chess. 



Flowering glumes compressed-keeled. 



Palet less than -J^ as long as the flowering glume. 



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

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

 Palet more than % as long as the glume. 3. B. unioloides. 



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



Flowering glumes oval or broadly elliptic ; second empty glume S-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. tectoriim. 



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



14. B. sterilis. 



1. Bromus polyanthus Scribii. 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 Caiion ; Rabbit-Ear Pass ; Keblar Pass ; Robin- 

 son, Summit Co.; Walsenburg; Veta Pass; foot of Alt. Richtofen, on the 

 Michigan ; near Chambers' Lake ; Cameron Pass. 



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

 Calif. — Alt. 5000-6000 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 

 Bor.lder. 



