136 THE TRUE GRASSES. 



e. Flowering glumes with five sharp, subulate divi- 

 sions, which are bent backwards. Spikelets two- 

 flowered ; inflorescence capitate. . 206. Echinaria. 



f. Flowering glumes with 3-5 lanceolate, pointed, 

 rigid, and erect or straight lobes. Spikelets many- 

 flowered, in racemes 207. Orcuttia. 



g. Flowering glumes with five delicate awns. 



210. Sesleria, Sec. Psilathera. 



h. Flowering glumes five-cleft, divisions awl-shaped, 

 the middle and two outer ones awned. 



199. Calamochloa. 

 NOTE. Compare Triraphis. 



i. Flowering glumes deeply 3-4-cleft-with a dorsal 



awn 201. Pommoreulla. 



k. Flowering glumes deeply four-cleft, usually awned 



between the hyaline divisions. 200. Cathestechum. 

 1. Flowering glumes of the fertile flower three-cleft, 



three-awned. 



a. Plant dioacious, the two sexes very unlike. 



202. Scleropogon. 



ft. Plant hermaphrodite. . . . 203. Triraphis. 

 B. Floivering glumes entire or two-toothed to two-deft, awn- 

 less or ivith one awn (3-5-atvned only in a variety of 

 Bromus macrostachys). 



a. Rachilla or flowering glume (at least of the fertile 

 flower) with long hairs which envelop the latter. 

 Tall, reed-like grasses. 



a. Plant dioecious, $ spikelets hairy, $ spikelets 



naked 214. Gynerium. 



ft. Plant hermaphrodite (very rarely dioacious), all 

 the spikelets hairy. 



I. Flowering glumes thick-membranaceous, 

 five-nerved. . . . 215. Ampelodesmos. 

 II. Flowering glumes thin-membranaceous or 

 hyaline, three-nerved. 



1. Flowering glumes hairy, rachilla naked. 



216. Arundo. 

 2. Hairs on the rachilla only. 



217. Phragmites. 



b. Rachilla and flowering glume naked or hairy; 

 hairs much shorter than the glumes. 



