338 GRASS ORDER 



(h) Lemma distinctly 

 nerved; style pres- 

 ent Panicularia 

 (i) Lemma faintly nerved ; 



style none Puccinellia 



s. Stigmas arising below the tip 

 of the ovary ; spikelets large, 

 usually awned Bromus 



b. Spikelets 1-flowered, often with an extra or 

 sterile lemma 



(1) Spikelet with lemma and palet alone, the 



glumes none Homalocenchrus 



(2) Spikelet with glumes as well as lemma and 



palet 



(a) Spikelets in pairs or threes, one stalked, 



the other stalkless 

 x. Spikelets in spike-like clustered or 



panicled racemes Andropogon 



y. Spikelets in panicles 



(x) Stalked spikelet reduced to a pedi- 

 cel Chrysopogon 

 (y) Stalked spikelet present Sorghum 



(b) Spikelets not in pairs 



x. Two extra glumes or hairy stalks be- 

 tween the glumes and the lemma and 

 palet 

 (x) Spikelets with a perfect flower 



alone Ph alar is 



(y) Spikelets with 1 perfect and 2 stam- 



inate flowers Hierochloe 



y. Spikelets without 2 extra glumes 



(x) Lemma and palet hyaline, thinner 

 than the glumes 

 m. Lemma awned at the tip, the awn 

 usually long 

 (m) Spikelets in pairs in a spike- 

 like cluster Lycurus 

 (n) Spikelets not in pairs 

 r. Lemma thin and papery Muhlenbergia 

 s. Lemma thick and hard 



(r) Awns 3-forked Aristida 



