GRASS FAMILY 171 



Panicle open, the branches spreading. 

 Awn short or wanting. 



Lemmas broad, obtuse 7. B . brizaeformis. 



Lemmas acuminate 18> B unio i oides . 



Awn well-developed (cf. B. carinatus). 



Awn twisted and bent j p trinii 



Awn not twisted and bent. 



Sheaths smooth; florets turgid; awn iy 2 to 2^ lines long 2. B. secalinus. 



Sheaths pubescent; awn usually long. 



Awn 1% to 2 inches long 10 B v m osus . 



Awn not more than 8 lines long. 



First glume 1-nerved 12. B . tectorum. 



First glume 3-nerved. 



Lemmas pubescent 6. B. arenarius. 



Lemmas glabrous. 



Awns all alike 3. #. commutatus. 



Awns of the lower florets shorter 5. B . japonicus. 



Plants perennial. 



Spikelets subterete, not strongly flattened. 



Panicle narrow, the branches erect 17. B . suTcsdorfii. 



Panicle open, the branches spreading. 



Branches of panicle stiffly divaricate; blades short 13. B. orcuttianus. 



Branches drooping; blades elongated. 



Lemmas pubescent throughout 14. B. grandis. 



Lemmas pubescent at margins or base only, or nearly glabrous. 



Lemmas densely pubescent at base and margins; lower glume 3-nerved 



16. B. laevipes. 

 Lemmas sparsely pubescent on back, ciliate on margins or nearly glabrous; lower 



glume 1-nerved 15. B. vulgaris. 



Spikelets strongly flattened. 



Blades canescent and densely pilose, narrow or involute 19. B. subvelutinus. 



Blades not canescent, glabrous or somewhat pilose, broader, flat. 



Panicle narrow, the branches short and erect 21. B. maritimus. 



Panicle open, the branches spreading or drooping. 



Awn less than 3% lines long; blades rather broad 20. B. marginatus. 



Awn more than 3% lines long; blades usually narrow 22. B. carinatus. 



DIVISION I. Introduced annuals (cf. B. unioloides in Div. 3). 



1. B. trinii Desv. Culms erect, 1 to 2 feet high; sheaths pilose or nearly 

 smooth ; blades usually pilose ; panicle narrow, 4 to 8 inches long, rather dense ; 

 spikelets narrow, 5 to 7-nowered, 7 to 10 lines long; glumes lanceolate, acu- 

 minate, smooth, the first mostly 1-nerved, 4 to 5 lines long, the second broader, 

 mostly 3-nerved, 6 to 8 lines long; lemmas coarsely and sparsely pubescent, 

 5-nerved, 6 to 7 lines long, acuminate, with 2 narrow teeth 1 line long; awn 

 7 to 10 lines long, twisted below, bent below the middle and strongly divaricate 

 when old. 



Dry plains and rocky or wooded slopes: Klamath Bluffs, Siskiyou Co. (Butler 

 1185) ; San Francisco and Contra Costa cos. south, especially in desert regions; 

 east to Colorado and south to Mexico ; also Chile. 



Var. excelsus Shear. Lemma 7-nerved, the awn scarcely twisted or bent 

 A little known form which may prove to be a distinct species. The type is from 

 the Panamint Mts. (Coville & Funston 522). Another specimen, Wilder 1062, 

 from Glenavon, is doubtfully referred to this variety. 



Kefs. BROMUS TRINII Desv. in Gay, Fl. Chil. 6: 441. 1853; Abrams, Fl. Los Ang. 53. 1904. 

 Var. pallidiflorus Desv. in Gay, Fl. Chil. 6: 441. 1853; Abrams, Fl. Los Ang. 54. 1904. Trise- 

 tum barbatum Steud. Syn. PI. Glum. 1: 229. 1854; Davy in Jepson, Fl. W. Mid. Cal. 52. 1901. 

 Var. EXCELSUS Shear, U. S. Dept. Agr. Div. Agrost. Bull. 23: 25. 1900. 



