50 



TRIRAPHIS. 



1. Perennial 2 



Annual 3 



2. Culms many noded, profusely branched. T. ramosissuua. 

 Culms about 3 noded simple T. rehmanni. 



3. Valves f lin. long. A dwarf grass T. nana. 



Valves about IJ lin. long 4 



4. Culms 5-7 noded. Middle awn about twice length of the 



^valve T. elliotii. 



Culms 1-2 noded. Middle awn about as long as valve 5 



5. Culms with scattered, long, spreading hairs. Glumes 



smooth T. fleckii. 



Culms glabrous, scaberulous or sometimes scantily hairy. 

 Glumes scaberulous T. purpurea. 



TRISTACIIYA. 



1. Glumes glabrous T. rehmanni. 



Glumes hairy with bristle-bearing glands 2 



2. Glumes equal, 10 lin. long T. biseriata. 



Glumes unequal, lower 9-12, upper 14-18 lin. long ... 



T. leucolhrix. 

 UROCHLAENA. 



Culms 3-4 in. long, 3 noded U. pusilla. 



Culms 4-6 in. long, 4 noded (perhaps only a robust 

 variety of U. pusilla) U. major. 



VULPIA. 



Uppermost internode enclosed. Upper glume 1 nerved. 



V. myurus. 



Uppermost internode long, exserted. Upper glume 3 



nerved V. bromoidcs. 



