662 GR AMINES. 



MUHLENBERGIA, Schreber. 



M. arenieola, Buckley. Culms tufted, simple (2° high) ; leaves short, 

 flat, narrow-linear ; panicle terminal, long-peduncled, simple, spreading ; 

 palese 3-nerved, bearded at the base, four times as long as the oval obtuse or 

 acute glumes, and equalling the rough awn. (M. caespitosa, Chapm.) — Dry- 

 pine barrens, Florida, and westward. 



M. sylvatica, T. & Gr. Culms diffuse, branched (2° -3° high) ; pani- 

 cles contracted ; paleae as long as the nearly equal short-awned glumes, the 

 lower one with its awn 2-3 times the length of the spikelet. — North Caro- 

 lina, Tennessee, and northward. 



CALAMAGROSTIS, Adans. 



C. brevipilis. Gray. Culms tufted, simple (2°-3° high) ; leaves linear, 

 setaceousiy attenuate ; panicle long, narrow ; glumes ovate-lanceolate, the 

 upper one barely shorter than the paleaj, the lower one half as long; paleae 

 bearded on the back, twice as long as the hairs at their base, awnless ; rudi- 

 ment of a second flower none. — East Florida, and northward. 



THURBERIA, Benth. 



Low tufted annual grasses, with erect branching culms, soft-hairy leaves, 

 and 2-flo\vered spikelets in an erect narrow terminal panicle. — Glumes 2, 

 unequal, 3nerved, hispid. Paleas 2, included, the lower one smooth, coria- 

 ceous, armed below the apex witli a stout bent dorsal awn ; the upper one 

 thin, with an awn-like pedicel at its base. Stamens 2. Grain free. 



T. Arkansana, Benth. Culms 6' -12' high. Leaves shorter than the 

 culm ; panicle 2' - 3' long. — On a shell mound near Apalachicola. April. 



ARISTIDA, L. 



A. simpliciflora, Chapm. Culms filiform (2° high), forking ; leaves 

 flat, smoothish ; racemes simple, straight (()'-9' long), loosely flowered; 

 glumes nearly equal, awn-pointed, tlie lower one rough on the keel, longer 

 than the paleae; middle awn circular-curved near the base. — Damp pine 

 barrens. West Florida. 



A. gyrans, Chapm. Culms simple (1° high), purple; leaves convolute- 

 filiform ; panicle simple, with the branches appressed ; lower glume truncate, 

 short-awned, as long as the pales, tlie upper one a third longer, attenuate ; 

 paleae long-stipitate, the awns nearly equal, curved. — Keys of Caximbas 

 Bay, South Florida. 



A. COndensata, Ciiapm. Culms stout, simple (2° high) ; leaves rigid, 

 flat or concave, soon convolute; panicle (\°-\\° long), long-peduncled, con- 

 tracted, densely many-flowered ; glumes equal, awn-pointed, longer than the 

 palese; awns straight, longer than the glumes. — Dry sandy pine barrens, 

 West Florida. 



