452 POACE^. 



of the apex, with awns projecting between the lobes; palea two- 

 thirds as long as its glnme, 2-nerved, with two projecting awns; 

 floral glnme of lower floret of terminal spikelet like those of the 

 lateral spikelets, only a little longer; floral glume of neutral floret 

 of terminal spikelet broadly oval, 4-lobed for half its length or 

 more, with 3 projecting awns between the lobes; palea smaller tlian 

 in pistillate florets. Ovary obovate, styles distinct, with long pur- 

 plish hairs on two-thirds of tlie upper portion. On stamvnate 

 splices, lateral spikelets with 2 florets and a third rudiment. Lower 

 empty glumes of lateral spikelets minute, broadly truncate ; of ter- 

 minal spikelet smaller, narrower. Upper emi^ty glume of lateral 

 flowers 2 mm long, elliptical-lanceolate, compressed, inequilateral, 

 1-nerved; of terminal spikelet oval, 3-nerved; floral glume 2 mm. 

 long, oblong, 4-lobed for one-third of its length, with awns be- 

 tween the lobes; palefe oblong-lanceolate, as long as their glumes, 

 with two parallel nerves slightly projecting. Stamens 3. 

 There are tliree species found in Texas and Mexico. 



1. C. erectum Vasey & Hack. Bull. Torr. Club. 11:37 (1884) 

 and 14:100 (1887). 



A tufted erect perennial, 15-30 cm. high, stdloniferous, nodes 

 villous; light green, tinged with purple. Ligule a ciliate ring; 

 blades of sterile shoots 5-8 cm. long, narrow, flat or becoming 

 involute, slightly hairy on the margins and upper surface. Culms 

 simple or branching. Spikes about 3 cm. long, containing 5-9 

 clusters of spikelets. Spikelets of the sterile spike 7 mm. long. 



Texas and Mexico. 



2. C. Mexicanum Presl, Eel. H^nk. 1 : 205, t. 42 (1830). 

 Nodes sniootli, spikelets of the sterile spikes shortly pubescent, 



4-5 mm. long; very variable and apparently only a variety of C. 

 erectvm V. & H. 



West Texas. Travard G2. 



3. C. prostratum Presl, 1. c. 



Slieaths ciliate at the throat. Lower leaves 1-4 cm. long, up- 

 per shorter. Spikelets of the sterile spikes nearly smooth, 3-4 mm. 

 long. Description incomplete for want of abundant material. 



Mexico, Palmer 270. 



