GRASS FAMILY 339 



(s) Awns simple 



h. Awns twisted, persistent STIPA 

 i. Awns straight, falling off 

 (h) Lemma with long 



silky hairs ERIOCOMA 



(i) Lemma smooth or 



finely hairy ORYZOPSIS 



n. Lemma usually awnless or awned 



from the back 

 (m) Spikelets in a single dense 



spike 

 r. Spikelets falling from the axis ; 



awn on the back ALOPECURUS 



s. Spikelets persistent ; awn none 



or short PHLEUM 



(n) Spikelets in a panicle 



r. Lemma with a tuft of hairs at 



base 



(r) Lemma thin and papery CALAMAGROSTIS 

 (s) Lemma hard and leathery CALAMOVILFA 

 s. Lemma without a tuft of hairs 

 (r) Lemma awned on the back 

 h. Glumes awned POLYPOGON 



i. Glumes acute 



(h) Palet 1 -nerved; sta- 

 men 1 t CINNA 

 (i) Palet 2-nerved or 



none ; stamens 3 AGROSTIS 

 (s) Lemma not awned 

 h. Grain permanently en- 

 closed in lemma *and 

 pale; AGROSTIS 



i. Grain not permanently en- 

 closed 

 (h) Stamen 1 ; stigma at 



tip of glumes PHIPPSIA 



(i) Stamens 2-3 ; stigma at 



side of glumes SPOROBOLUS 



(y) Lemma like the glumes, or thicker 

 and firmer 



