ORDER 156. GRAMINEJ3. 785 



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

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

 t> 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, ligules ciliate; pans large, pyramidal, terminal and axillary, smooth; 

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

 as the upper ; abortive fl., with 1 pale.-~CD Marshes, especiaDy 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, lwer glume very small, upper very large, 1 1-veined, remarkably 

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

 JL Sept. (P. Elliottianum SchL) 



5 P. hlans EL. 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 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, l^-~-3f high, often genicu- 

 late at base ; Ivs. long and numerous, cauline 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^ lancc- 

 ovate, acute, crowded ; upper glume ^veined, ji longer than the loiver ; upper neu- 

 tral, pale, nearly as long as the lower. -^ -2f Meadows, frequent. July. (P. fusco- 

 rubens Nutt.) 



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

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

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

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

 upper pale half as long as the lower pale, scarcely sJtorkf than the Jertile fio-uaer , up>- 

 per glume 7-femed "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, Ian* 

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

 shorter than the lower pale (while in Nos. 6 and 7 it is longer than the lower 

 pale !). "Wet meadows, E. Tenn. I Jl., Aug. 



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

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

 shorter than the joints ; pan* larg&, 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.- 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 5f high; Ivs. flat, long, 

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

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

 2A'' long, very pointed, divaricate, the lower as long as the upper; pales of tho 

 abortive flower nearly equal, enfolding the purple stamens, Zf Salt-lick prairies, 

 fields, &c., N. Y. to Ind., S. to tho Gulf. Aug. 



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

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

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

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

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

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



12 P. fragile Kunth. Culm geniculate at base, assurgent, branched, v^nj brittle. 



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