POACEAE 



93 



28. MUHLENBERGIA. 



29. Brachyelytrum. 



32. Alopecurus. 

 34. polypogon. 



31. Phleum. 



30. Heleochloa. 



Awn 3-parted. 27. Aristida. 



Flowering scale membranous, not firmer than the empty 

 scales. 

 Flowering scale with a terminal awn or awn-pointed, 

 tightly enclosing the grain. 

 Rachilla not prolonged beyond the base of the 



flowering scale; empty scales usually evident. 

 Rachilla extending beyond the base of the flowering 

 scale as a bristle-like appendage; empty scales 

 minute, the first sometimes wanting. 

 Flowering scale awnless, or with a dorsal awn, loosely 

 enclosing the grain. 

 Spikelets readily deciduous, entire at maturity. 

 Empty scales awnless. 

 Empty scales awned. 

 Spikelets not deciduous entire, the empty scales 

 persistent, flowering scales usually decidu- 

 ous. 

 Empty scales awned. 

 Empty scales awnless. 



Flowering scales 1 -nerved. 



Panicle dense and spike-like, the 

 spikelets markedly compressed lat- 

 erally, ciliate on the keel. 

 Panicle open or narrow, the spikelets 

 not markedly laterally com- 

 pressed, the keel glabrous. 

 Grain loosely enclosed in the 

 pericarp, from w-hich it readily 

 separates and falls at ma- 

 turity; flowering scales with 

 no hairs at the base. 

 Grain adherent to the pericarp 

 and not separating from it at 

 maturity; flowering scale with 

 a ring of long hairs at the base. 

 Flowering scales 3-5-nerved. 



Stamen 1; flowering scale stipitate; 



palet usually i-nerved. 

 Stamens 3; flowering scale sessile; 

 palet 2-nerved. 

 Rachilla not prolonged beyond 



the flowering scale. 

 Rachilla prolonged beyond the 

 flowering scale. 

 Prolongation of the rachilla 

 glabrous; flowering scale 

 glabrous at the base, and 

 with a long awn just 

 below the bifid apex. 40. Apera. 



33. Sporobolus. 



39. Calamovilfa. 



35. Cinna. 



36. ac.rostis. 



