V82 Oedee 156.— GRAMINB^. 



3 P. setaceum Mx. Culm ascending from a decumbent base, very slender, 1 to 

 2f, with very remote joints; Ivs. lance-linear, 3 — T by 2 — 3", ciliate and soft 

 hairy; sheaths pubescent, upper one very long; spike generally solitary, often 2, 

 on a long, very slender peduncle, sometimes with another scarcely exserted from 

 the sheaths; spilcelets plano-convex, with the flat side out, f" diam., 1 or 2 on 

 each very short pedicel, appearing 2 — 3-rowed in the 1-sided spilce. — Dry-fields, 

 Mass., to 111. and S. States. Aug. (P. debile and ciliatifolium Mx.) 



/3. LONGIPEDUNODLATDM. Larger, less hairy, and spilcelets evidently 3-rowed. 

 — S. States. (P. longip. LeC.) 



4 P. IcGve Mx. Culm erect, rather firm, 18' — 3^ glabrous; Ivs. generally smooth, 

 pilous only at the base, broadly linear; lower sheaths sometimes hairy, spikes 

 2 — 6, alternate, spreading, with a few long, white hairs at the base ; spikelets in 2 

 rows ; rachis fiexuous, flat on the back ; pedicels undivided, with one spikelet ; 

 spikelets twice as large (IJ'' diam.) as in- the preceding ; glume orbicular-ovate, 

 3- veined. — Grassy banks of rivers, Conn, to Ind. and S. States. Aug. Quite vari- 

 able, including several reputed species. 



p. uNDULosuM. Lvs. rather long and broad, -^th wavy-margins. (P. Lecon- 



tianura Schult.) 

 ■y. Floridanuii. Spikelets enlarged (near 2" long), glume 5-veined. (P. ma- 



crospermum JFlgg.) 

 6. ALTissiMOM. Strict and taU ; sheaths much compressed. (P. altissimum LeC.) 



5 P. angustifolium Le Conte. Culm erect, wiry, glabrous, 2f high ; lvs. glab- 

 rous, narrowly linear, almost setaceous, compressed carinate, 9 to 18' long ; sheaths 

 long, smooth; spikes 2 or 3, alternate, divaricate, 1 to 2' img, with a few hairs at 

 base ; spikelets orbicular, 1" diam. in 2 rows, with a very narrow rachis.-^ 2^ Wet 

 places, Ga., Pla. to La. A distinct species. Seeds blackish. 



6 P. dasyphyllum Ell. Culm decumbent at base, 12 to 30' high, glabrous; 

 lvs. broadly linear, clothed with copious soft hairs as well as the long sheaths ; 

 spikes 2 to 4, large, spreading, the ped. shghtly exserted from the upper sheath ; 

 spikelets oval, obtuse, large, in 3 rows ; teeth of the rachis 2-flowered. — Dry fields, 

 S. States, common. ;^? Jl. — Oct. 



7 P. latifolium Le Conte. Glabrous; culm erect, stout, tall (2 to 3f), from a 

 shghtly decumbent base ; lvs. fiat, large, lance-linear, 6 to 12' by 5 to 10", margins 

 ciliate ; sheaths hairy at throat, shorter than the long internodes ; spikes 2 to 4, 



2 to 4' long, alternate, suberect, pilous at base; spikelets large (IJ" diam.), in 



3 rows on the narrow, flexuous rachis. — y Car. to Ela. and La. 



8 P. tenue Kunth. Glabrous; culm erect, very slender; his. narrow, very long, 

 ciliate on the margins, sheath ciliate; spikes 4 or 5, very slender, alternate, 

 spreading, hairy at base ; spikelets orbicular, in 3 rows ; rachis flexuous, narrow, 

 tne teeth 2-flowered. — If. N. J. to Ga. (Le Conte). Differs from No. 5, in its ciliate 

 lvs. and 3-uerved spikelets. 



9 P. arundindceum Poir. "Glabrous; hs. somewhat sword-shaped (com- 

 pressed-oarvnate), the margin scabrous ; spikes alternate, elongated ; spikelets in 

 3 rows ; gls. (gl. and pale) equal, obtuse. — Carolina." Poiret. 



10 P. precox Walt. Glabrous throughout ; culm erect ; lvs. lance-linear, very 

 long ; spikes 3 to 5, alternate, dense-flowered, with a tuft of long hair at base ; 

 raclds linear, straight (not fiexuous), narrower than the 3 rows of very smooth, 

 orbicular, compressed spikelets; gls. 3-veined. — If Wet places. Car. to Fla. May. 

 — Aug. (P. lentiferum Lam.) 



11 P. fliiitans Kunth. Culm decumbent and ascending 10 to 20', generally 

 floating ; lvs. scabrous, lance-linear, 2 to 5' by 4 to 6" ; sheaths inflated, open, 

 ciliate at base ; spikes 20 to 60, 1 to 2 J' long, the lower somewhat verticillate ; 

 rachis fohaceous, nearly 1" broad, covering the 2 rows of ovate, acute spikelets 

 and projecting in a point heyond them. — CD River swamps, S. Ill to Va. and S. 

 States, Oct. (P. mucronatum Muhl. Ceresia, Ell.) 



12 P. 'Walterianum Sohult. Culm decumbent, branching, ascending; lvs. 

 glabrous, lance-linear, 2 to 4' by 3 to 5" ; sheaths open, all glabrous ; spikes 2 or 

 3 on each bramh, 1 to 2' long; raehis very broad (near 2"), covering the 2 rows 

 of oval, acute spikes but not projecting beyond them. — dlWet soils. Car. to Fla. 

 and La. Jl. — Sept. (P. vaginatum EIL) 



