► 94 FLORA OF TEXAS. 



** Glumes 2, the lower one of ten minute, rarely wanting. 



Spikelets single, without a bristly or spiny involucre Panicum. 



single, or few in a cluster, inclosed in an indurated and spiny involu- 

 cre; spikelets spiked Cenchuus. 



Spikes and spiktlets as in RoUbxllia, bul ihe flowers as in ranicum.. STEnorxi-HJivyi. 



Tribe IX. Rottboelliacese. Spikelets 1-2-flowcrecl, 

 by pairs, imbedded iii an excavation of the'' thick and 

 jointed rachis, one stalked and imperfect, the other 

 sessile and perfect ; or the upper spikelets all staminate 

 and the lower pistillate. Loiuer glume coriaceous or car- 

 tilaginous. Palece awnless. 



Spikelets 2 on each joint, one stalked and sterile, the other sessile and perfect. 



ROTTBCELLIA, 



2 on each joint, the one at the top of the joint sterile, the other at the 



base globose and fertile Manisuuis, 



Upper spikelets by jmirs, all staminate ; the lower ones single, and pistillate. 



TniPSACUM. 



Tribe X. Andropogoneae. Spikelets 2-3 on each 

 joint of the slender hairy or plumose rachis. Glumes more 

 rigid than the thin-awned paleae. 



Spikelets 2 on each joint of the plumose or hairy rachis, one sessile and perfect, 

 the other stalked and imperfect or rudimentary Andropogon. 



2 on each joint of the rachis, both fertile and surrounded by a hairy 



involucre Erianthus. 



panicled, 2-3 together, the latter ones rudvnentary Sorghum. 



LEERSIA, Swartz. False Rice. 



Perennial aquatic or marsh grasses, with the leaves 

 and sheaths rougliened with minute recurved points, the 

 1-flowered (whitish) spikelets crowded in 1-sided panicled 

 racemes; pedicels jointed; ghimes none; ^^^to 2, charta- 

 ceous, strongly compressed, fringed on the keel, the lower 

 one much Avider ; stamens 1-6 ; stigmas 2 ; grain com- 

 pressed. 



L. ORYZOIDES, Swartz. Panicle large, diffuse ; spikelets 

 oblong, flat, loosely imbricated; stamens 3. Ditches and 

 swamps. July and August. Cuhn 3°-4° long, commonly 



