96 Festuceae Bromus 



First glume 1-nerved (rarely 3-nerved in Bromus latiglumis, the leaves of which have 

 prominent flanges at the base). 

 Awns 12-25 mm long, straight. 



Spikelets glabrous or more or less scabrous ; awns about 25 mm long 



1. B. sterilis. 



Spikelets pubescent; awns mostly 12-17 mm long 2. B. tectorum. 



Awns less than 12 mm long or sometimes lacking. 



Branches of panicle compact, erect or slightly spreading at maturity; glumes 

 and lemmas glabrous or more or less scabrous but not pubescent; sheaths 

 usually glabrous. 

 Creeping rhizomes present; sheaths glabrous (sometimes late shoots pubescent) ; 



lemmas awnless or with awns up to 3 mm long 3. B. inermis. 



Creeping rhizomes lacking; sheaths glabrous or somewhat pilose; lemmas with 



awns 5-6 mm long. (See excluded species no. 42, p. 1025.) B. erectus. 



Branches of panicle loose, drooping; glumes and lemmas more or less pubescent; 



sheaths usually pubescent. 



Glumes glabrous except the scabrous midnerve or sometimes the whole surface 



more or less scabrous. 



Nodes usually 4-6; lemmas strongly pubescent near the margin on the lower 



half to three-fourths, their backs glabrous or scaberulous; plants of a 



marsh or prairie habitat, flowering in July 4. B. ciliatus. 



Nodes 10-20; lemmas more or less pubescent, especially on the back; plants of 

 dry woods, ravines, and dry banks of streams, flowering from July to 



September 5. B. latiglumis. 



Glumes more or less pubescent all over; lemmas more or less pubescent, 

 especially on the back ; plants of dry woods, ravines, and dry banks ; plants 

 flowering from May to July. 

 Nodes 4-6; sheaths shorter than the internodes or the lower ones longer, not 

 flaring at the summit. 



Sheaths and blades more or less villous 6. B. purgans. 



Sheaths and blades (except the lower ones) glabrous 



6a. B. purgans f . laevivaginatus. 



Nodes 10-20; sheaths longer than the internodes, at least the 4 lower ones 



longer; plants flowering from July to September 5. B. latiglumis. 



First glume 3- or 5-nerved. 



Sheaths glabrous 7. B. secalinus. 



Sheaths pubescent. 



Lemmas awnless or with awns less than 5 mm long. 



Glumes and lemmas glabrous or scabrous on the nerves; awnless or with short 



awns 8. B. brizaeformis. 



Glumes and lemmas silky-pubescent all over ; awns mostly 2-3 mm long 



9. B. Kalmii. 



Lemmas with awns more than 5 mm long. 



Glumes and lemmas more or less silky-pubescent 10. B. mollis. 



Glumes and lemmas glabrous or somewhat scabrous. 



Branches of the panicle rather stiffly spreading or drooping, not flexuous; 



awns straight 11. B- commutatus. 



Branches of the panicle slender, lax or flexuous 12. B. japonicus. 



1. Bromus sterilis L. Map 120. Our only report of this species is of 

 a colony which I found along Tanners Creek about a half mile southeast 

 of Guilford, Dearborn County. It was well established here along the 

 roadside. 



Nat. of Eu. ; N. E. to 111., southw. to Va. and Ala., and in the west from 

 B. C. to Calif, and Colo. 



