27 



4. Spikelets 2-2£ lin. long. Valves with clavate tipped cilia. 



B. acutiflorum. 



Spikelets l£-2 lin. long. Valves with acute cilia or 



bristles 5 



5. Spikelets finely hirsute all over. Glumes with bristles. 



B. ciliare. 



Leaves glabrous (except at the mouth). Glumes 



glabrous 6 



6. Uppermost sheath usually exceeding base of panicle. 



B. obliterum. 



Uppermost sheath remote from the panicle 



B. glomeratuni. 

 BROMUS. 



1. Glumes and valves strongly compressed, acutely keeled. 



Valve about 13-nerved B. unioloides. 



Glumes and valves not both strongly compressed and 

 keeled. Valves fewer than 13 nerved 2 



2. Valves 1 in. long. Lower glume 7-10 lin. Upper glume 



11-14 lin. Awn 2-2h in B. maximus. 



Valves less than § in. long. Lower glume less than 7 lin. 

 long. Upper glume less than 8 lin. long. Awn much 

 shorter 3 



3. Perennial, often tall. Lower glume 1-3 nerved, upper 



3-5 nerved 4 



Annual. Lower glume 3-5, rarely 1-nerved, upper 5-9 

 nerved 7 



4. Lower glume 1 (rarely 3), upper 3-nerved. Anthers 1-1£ 



lin. long B. leptoclados. 



Lower glume 3, upper usually 5-nerved. Anthers about 

 3 lin. long 5 



5. Spikelets glabrous. Valves prominently nerved ... 



B. natalensis. 

 Spikelets hairy. Valve nerves not prominent 6 



6. Florets rather loose. Valves linear-lanceolate, narrow. 



B. speciosus. 



Florets close. Valves lanceolate-cuneate, rather broad 



above B. firmior. 



7. Panicle contracted, dense. Branches shorter than the 



spikelets B. molliformis. 



Panicle loose. Lower branches much longer than the 

 spikelets, flexuous 8 



8. Panicle becoming effuse. Branches 3-5 in. long ... 



B. arvensis. 

 Panicle more or less secund. Branches less than 2 in. 



long 9 



3 



