ORDER 156. GRAMINE.E. 785 



spikelets oblong-lanceolate, acute, glabrous ; glumes veiny, very unequal, the lower 

 minute. Sand hills, Mason Co., 111. (Mead, in Gray's Manual). 



3 P. proliferum Lam. Culm assurgent, geniculate at base, very smooth, thick 

 and succulent; Ivs. linear-lanceolate, 4 to 6'' wide, 10 to 15' long, on tumid 

 sheaths, hairy at throat; pan. large, pyramidal, terminal and axillary, smooth; 

 spikelets oblong, acute, veiny, 1" long, densely racemed ; lower glume i as long 

 as the upper ; abortive fL, with 1 pale. CD Marshes, especially brackish and 

 sandy, Mass, to La., also along the Western rivers. Aug., Sept. (P. geniculatum 

 Muhl.) 



4 P. gibbum Ell. Culm terete, assurgent, 2 to 3f, with black joints ; Ivs. lance- 

 linear, glabrous, 4 to 8' by 4 to 8'', on smooth, strongly striate sheaths; pan. 

 densely contracted, often purple, fusiform, about 6' long, strict ; spikelets near 2" 

 long, obtusish, lower glume very small, upper very large, 11-veined, remarkably 

 gibbous at base, upper pale nearly as long as the lower. CD Wet soils, S. States. 

 JL Sept. (P. Elliottianum Schl.) 



5 P. hians Ell. Culm very slender, almost filiform, decumbent and rooting at 

 the lower joints, about 2f high; Ivs. narrpwly linear, 8 to 16' long, glabrous; 

 sheaths hairy only at the throat; panicle pyramidal, spikelets racemed. " long; 

 lower glume half as long as the upper, neutral pales equal, conspicuous (gaping), 

 a little longer than the fertile. Damp pine barrens, S. States, common. Aug. 

 Oct. (P. debile Poir. P. divaricatum MX.) 



6 P. agrostoides MuhL Culm compressed, glabrous, II Sfhigh, often genicu- 

 late at base ; Ivs. long and numerous, cauline linear-lanceolate, carinate, rough- 

 edged, on short, striate sheaths; panicles terminal and lateral, pyramidal, com- 

 posed of racemed, spreading or deflexed branches; spikelets 1" long, purple, lance- 

 ovate, acute, crowded ; upper glume 3-veined, % longer than the lower ; upper neu- 

 tral, pale, nearly as long as the lower. 1 Meadows, frequent. July. (P. fusco- 

 rubens Nutt.) 



7 P. anceps MX. Culm compressed, 2 to 3f; Ivs. linear, carinate, very long, 

 rough-edged ; sheaths ancipital, pilous on the throat and margin ; pan. erect, 

 pyramidal, with subremote, subsirnple, interruptedly racemous branches ; spikelets 

 H" long, lanceolate, very acuminate, and when mature, forked; lower glume and 

 upper pale half as long as the loWerpale, scarcely shorter than the fertile flower ; up- 

 per glume 1-veined. Wet soils, N. J. and S. States. Aug. Nov. 



8 P. vilfiforme. Glabrous throughout; culm decumbent, ascending 2 to 3f, 

 branched ; Ivs. long, linear, scarcely rough-edged ; sheaths with a tuft of hairs at 

 throat ; pan. simple, with racemed, spreading branches ; spikelets 2" long, lan- 

 ceolate, acute ; lower glume \ to % as long as the upper, 1 -veined glume which is 

 shorter than the lower pale (while in Nos. G and 7 it is longer than the lower 

 pale !). Wet meadows, E. Tenn. 1 Jl., Aug. 



9 P. amarum Ell. Glabrous, leafy ; culm 2 to 3f high, stout ; lus. glaucous, cor- 

 iaceous, rigid, linear, 10 to 18' long, margins involute, not scabrous; sheath some 

 shorter than the joints ; pan. large, contracted, its very smooth branches appressed ; 

 spikelets thick, 2" long, ovate, acuminate, lower glume nearly as long as the 

 sterile pales, which contain 3 orange-colored stamens. If. Sandy shores, Conn. 

 to Fla. and La. (Hale). Lvs. excessively bitter (Elliott). Aug. Oct. 



10 P. virgatum L. Glabrous and often purple ; culm 3 Sfhigh; Ivs. flat, long, 

 linear-lanceolate, hairy at base ; sheaths striate ; stip. with long, white cilia: ; 

 pan. pyramidal, loose, spreading, diffuse, very large ; Us. acuminate, the glumes 

 2" long, very pointed, divaricate, the lower f as long as the upper ; pales of the 

 abortive flower nearly equal, enfolding the purjjle stamens. 2 Salt-lick prairies, 

 fields, &.c., X. Y. to Ind., S. to the Gulf. Aug. 



11 P. verrucosum Muhl. Culm slender, decumbent and geniculate, branching 

 from tho base, 1 2f high ; Ivs. lance-linear, flat, 4 to 6' by 2 to 4", spreading, 

 smooth ; pan. much expanded, few-flowered ; spikelets \ to " long, covered with 

 warty points (verrucous) obovate, bluish ; abortive flower of one palea, and neuter. 

 'D ? Swamps and thickets, Mid. and S. States. Panicles terminal and lateral, loose 

 and capillary. Aug. (P. debilis Ell. nee Poir. P. ramulosum MX.) 



12 P. fragile Kufath. Culm geniculate at base, assurgent, branched, very brittle, 



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