ORDER 156. GRAMINEJE. 785 



(pikelets oblong-lanceolate, acute, glabrous; glumes veiny, very unequal, tho lower 

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

 2> P. proliferum Lam. Culrn assurgent, geuiculate at base, very smooth, thick 

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

 sheaths, ligules ciliate; pan. large, pyramidal, terminal and axillary, smooth; 

 spikelets oblong, acute, veiny, 1" long, densely racemed; lower glume 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.) In uplands more slender, not succulent. 



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, Ksvcr glumo very small, upper very large, 11- veined, remarkably 

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

 Jl. Sept. (P. Eiliottianum Schl.) 



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

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

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

 lower glumo 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. dcbilo Poir. P. divaricatum MX.) 



6 P. agrostoides Muhl. Culm compressed, glabrous, 1J 3f high, often genicu- 

 late at baso ; Ivs. long and numerous, caulino linear-lanceolate, carinate, rough- 

 edged, on short, striato 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. 2 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 tho throat and margin ; pan. erect, 

 pyramidal, with subremote, subsimple, interruptedly racemous branches ; spikekts 

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

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

 per glume 7 -veined. Wet soils, K 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- 

 ccolato, acute ; lower glume % to $ as long as the upper, ^-veined glume which is 

 shorter than the lower pole, -(while in ISfos. 6 and 7 it is longer than tho lower 

 pale !). Wet meadows, E. Tenn. I JL, Aug. 



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

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

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

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

 sterile pales, which contain 3 orange-colored stamens. 1 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. fiat, long, 

 linear-lanceolate, hairy at base; sheaths striato; stip. with long, white cilice; 

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

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

 abortive flower nearly equal, enfolding tho purpls stamens. If Salt-lick prairies, 

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



11 P. verniccsum 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, looso 

 and capillary. Aug. (P. debilis Ell. ncc Poir. P. ramulqsum MX.) 



12 P. fragile Kunth. Culnt gcuiculato at base, assurgent, branched^ very "brittle, 



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