34 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Panicle branches not greatly elongated. 



Panicle branches ascending, rather stiff, naked below, bearing 1 or 2 large 



spikelets. Washington 3. B. aleutensis. 



Panicle branches short and ascending or longer and drooping, with some 

 short branches at the base. 

 Blades canescent, densely pilose, narrow, often involute 



4. B. BREVIARISTATUS. 



Blades not canescent, glabrous or somewhat pilose, usually more than 

 3 mm wide 5. B. carinatus. 



Section 2. Bromopsis 



la. Creeping rhizomes present; lemmas awnless or short-awned; panicle erect, 

 somewhat open, the branches ascending. 

 Lemmas glabrous 6. B. inermis. 



Lemmas pubescent near the margins 7. B. pumpellianus. 



lb. Creeping rhizomes wanting (base of culm decumbent in B. laevipes). 

 2a. Panicle narrow, the branches erect. 



Lemmas glabrous or evenly scabrous 8. B. erectus. 



Lemmas appressed-pubescent on the margins and lower part. 



9. B. SUKSDORFII. 



2b. Panicle open, the branches spreading or drooping. 

 3a. Lemmas glabrous. 



Blades broad and lax, more than 5 mm, at least some of them 10 mm, 



wide. (var. laeviglumis) 15. B. ciliatus. 



Blades narrow, not more than 6 mm wide 18. B. texensis. 



3b. Lemmas pubescent. 



4a. Lemmas pubescent along the margin and on lower part of the back, 

 the upper part glabrous. 

 First glume 3-nerved; plant pale or glaucous. Culms decumbent at base. 



13. B. LAEVIPES. 



First glume 1 -nerved, or only faintly 3-nerved near the base; plants 

 dark green. 

 Ligule prominent, 3 to 5 mm long; lemmas narrow; awn usually 



more than 5 mm long 14. B. vulgaris. 



Ligule inconspicuous, about 1 mm long; lemmas broad; awn 3 to 5 mm 



long 15. B. ciliatus. 



4b. Lemmas pubescent rather evenly over the back, usually more densely 

 so along the lower part of the margin. 

 Panicle branches short, stiffly spreading; blades short, mostly on lower 



part of culm 10. B. orcuttianus. 



Panicle branches lax or drooping; blades along the culm, mostly elongate. 

 Panicle small, drooping, usually not more than 10 cm long. Spikelets 

 densely and conspicuously pubescent. 

 Sheaths and blades sparsely pilose to subglabrous; blades mostly 



2 to 4 mm wide (rarely 5 to 6 mm) 19. B. anomalus. 



Sheaths and blades (except uppermost in some) conspicuously pu- 

 bescent; blades 5 to 10 mm wide 20. B. kalmii. 



Panicle larger, erect, the branches more or less drooping. Blades 

 mostly wide and lax. 

 Ligule 3 to 4 mm long; blades pilose above, scabrous or smooth 

 beneath; panicle large, open, the slender branches long, 



drooping 12. B. pacificus. 



Ligule short; blades pubescent or pilose on both surfaces, or 

 glabrous or scabrous. 

 Blades densely short-pubescent on both surfaces. 



11. B. GRANDIS. 



Blades more or less pilose or glabrous. 



Sheaths, at least the lower, retrorsely pilose; blades mostly 

 more than 5 mm wide. 

 Sheaths shorter than the internodes; nodes 4 to 6. 



16. B. PURGANS. 



Sheaths longer than the internodes; nodes 10 to 20. 



17. B. LATIGLUMIS. 



Sheaths glabrous; blades mostly less than 5 mm wide. 



21. B. FRONDOSUS. 



