GEAMINEJE. C67 



smooth, oblong, faintly nerved ; lower glume nearly half as long as the 

 abruptly pointed upper one; palea) of the triandrous sterile flower nearly 

 equal. — South Florida. 



P. commutatum, Schultes. Culm smooth (2° high); leaves (3'-C 

 long) ovate-lanceolate, the margins and sheath ciliate ; panicle diffuse ; spike- 

 lets oblong, sparsely pubescent ; the upper glume and lower palea of the neu- 

 tral flower 7-nerved ; perfect flower acute. (P. nervosum, Ell.) — Dry woods 

 and margins of fields, Florida to North Carolina. 



P. sphaerocarpon, Ell. Culms rigidly erect (\\° -2° high); leaves 

 rigid, lanceolate, smooth, the rough margins near the base, and slieaths, cili- 

 ate ; panicle oval, diffuse ; spikelets small, oval, almost villous ; upper 

 glume 7-nerved ; upper palea of the neutral flower minute or wanting. — 

 Shallow grassy ponds, Georgia and Florida. 



P. consanguineum, Ennth. Smooth or villous ; culms (1°-1|° high) 

 at length excessively branched; leaves linear, erect; panicle long-pedun- 

 cled, the flexuous widely spreading branches few-flowered ; spikelets obo- 

 vate, pale, pubescent ; upper glume 7-nerved ; upper palea of the neutral 

 flower none ; perfect flower acute. (P. villosum and angustifolium, Ell. P. 

 setaceum, Muhl. P. subuniflorum, Bosc.) — Woods and borders of fields, 

 Florida to North Carolina, and westward. 



P. laxiflorum, Lam. Culms tufted, smooth (1° high) ; leaves lanceo- 

 late, acuminate, ciliate, mostly pale yellowish green (2' -3' long), the villous 

 sheaths shorter than the internodes ; panicle diffuse, plumose-bearded, rather 

 few-flowered ; spikelets scattered, oval, densely pubescent, the upper glume 

 7-nerved; neutral flower bipaleaceous ; fertile flower acute. (P. pubescens, 

 Michx., the culms pubescent, and the panicle more dense.) — Damp soil, 

 Florida, and northward. 



P. ramulosum, Michx. (in part). Low (6'-8' high), tufted, very 

 smooth and shining ; culm mostly purple ; leaves linear ; panicle diffusely 

 branched, many-flowered (l^'-2' long); spikelets minute, purple, very 

 smooth, the upper glume and neutral palea 5-nerved. — Low sandy pine 

 barrens, Florida and Georgia. 



CENCHRUS, L. 



1 C. incertus, M. A. Curtis. Smooth, strict, nearly simple, erect or as- 

 cending (2° -3° long); leaves linear, folded, the lower sheaths longer than 

 the internodes; spike cylindrical, many-flowered; involucre naked and acute 

 at base, the 10 or 11 stout spines ciliate ; spikelets geminate, smooth ; sterile 

 flower triandrous. (C. strictus, Chapm.) — Sandy coast, Florida to North 

 Carolina. 



C. myosuroides, H.B.K. Tall (4°-6° high); leaves long, rigid, con- 

 volute; spikes cylindrical, densely many-flowered; involucre small, 1-flow- 

 ered, armed with 20, or more, slender spines, as long as its strongly nerved 

 spikelet. (Panicum cenchroides, Ell.) — South Florida (Blodgett), Georgia 

 (Elliott). 



