POACEAE 



I05 



Panicle longer than broad. 

 Panicle nearly as long as 

 broad. 

 Spikelets over 2 mm. long. 

 Culms puberulent. 

 Culms glabrous. 



Leaf-blades cordate. 

 Leaf-blades not cordate. 

 Blades erect, ciliate 



toward the base. 

 Blades spreading, 

 glabrous. 

 Ligule 2-5 mm. long. 



Spikelets over 2 mm. long. 

 Spikelets less than 2 mm. long. 

 Panicle much longer than 

 broad. 

 Spikelet almost globose, 

 less than 1.5 mm. long. 

 Spikelet elliptic, densely 

 pubescent, over 1.5 mm. 

 long. 

 Panicle as long as broad. 

 Sheaths pubescent. 



Sheaths merely puberulent. 

 Sheaths pubescent with longer hairs. 

 Plants velvety. 



Spikelets over 2 mm. long. 

 Spikelets less than 2 mm. long. 

 Hairs on the sheath long and 



shaggy. 

 Hairs on the sheath short and 

 inconspicuous. 

 Plants not velvety. 



Spikelets ovate, pointed. 

 Spikelets not as above. 

 Spikelets less than 2 mm. 

 long. 

 Pubescence spreading. 

 Blades glabrous above 



or nearly so. 

 Blades pubescent on 

 the upper sur- 

 face. 

 Upper surface of 

 blades with short 

 appressed hairs. 

 Upper surface of 

 blades with 

 long erect 

 hair.,. 



23. P. polyanthes. 

 22. P. sphaerocarpon. 



59. P. Ashei. 



60. P. commutatum. 



31. P. boreale. 



32. P.ntattamitskeetense. 

 40. P. scoparioides. 



34. P. paucipilum. 



35. P. s prelum. 



36. P. Lindheimeri. 



59. P. Ashei. 



55. P. scoparium. 



47. P. lanuginosum. 

 30. P. annulum. 



56. P. scabriusculum. 



46. P. tennesseense. 



39. P. huachucae. 



