(GRASS FAMILY.) 579 



*+ Culm-leaves broadly lanceolate or wider, with 9-15 principal nerves. 



11. P. l:Ui folium, L. (excl. syn. Sloane, &c.) Culm (l-2 high), 

 smooth ; the joints and the orifice of the throat or margins of the otherwise 

 smooth sheaths often bearded with soft woolly hairs ; leaves broadly oblong-lanceolate 

 from a heart-clasping base (often 1' wide), taper-pointed, 11-15-nerved, smooth, 

 or sparingly downy-hairy; panicle more or less exserted (2' -3' long), usually 

 long-peduncled, the branches spreading ; spikelets obovate, l" long, downy ; low- 

 er glume ovate, not half the length of the many-nerved upper one ; sterile flower 

 often (but not always) with 3 stamens. 1|. (P. Walteri, Pom) Moist thick- 

 ets ; common. June - Aug. 



12. P. clandestiimin, L. Culm rigid (l-3 high), very leafy to the 

 top, at length producing appressed branches, the joints naked; sheaths rough with 

 papillce bearing very stiff and spreading bristly hairs ; leaves oblong-lanceolate 

 from a heart-clasping base, very taper-pointed ; lateral panicles and usually also 

 the terminal panicle more or less enclosed in the sheaths, or, in var. PEDUNCULA- ' 

 TUM (P. pedunculatum, Torr.), with the terminal one at length long-peduncled: 



otherwise resembling No. 11 ; but the spikelets more ovoid, often smooth; the 

 lower flower (always?) neutral. Low thickets and river-banks; rather com- 

 mon. July - Sept. 



13. P. microcarpon, Muhl. Culm and sheaths as in No. 11; the 



broadly lanceolate leaves nearly similar, but longer in proportion and less point* 

 ed, not dilated at the rounded bristly-ciliate base, very rough-margined, the up- 

 per surface roughish ; panicle soon exserted on a slender peduncle, very many- 

 flowered, narrowly oblong (3' -7' long) ; spikelets about " long, ovoid, smooth 

 or sinoothish ; lower glume orbicular and very small. 1|. (P. multiflorum, Ell. ? 

 notofPo/r.) Dry or moist thickets, Pennsylvania and Michigan to Illinois, 

 and southward. July -Sept. 



14. P. xaiitliopliysiuil, Gray. Culm simple, or at length branched 

 near the base (9' -15' high) ; sheaths hairy; leaves lanceolate, very acute (4'-6 x 

 long by ' wide), not dilated at the ciliate-bearded clasping base, smooth except the 

 margins, strongly - ll-nerved ; panicle long-peduncled, simple, contracted, the ap- 

 pressed branches bearing few roundish-obovate spikelets (about l" long) ; lower 

 glume ovate, acutish, one third or half the length of the 9-nerved upper one. 1J. 



Dry and sandy soil, Maine to Wisconsin, and northward ; rare. June. 

 Plant yellowish-green : spikelets minutely downy : sterile flower sometimes 

 staminate. 



15. P. vise id u m, Ell. Culms upright or ascending, at length much 

 branched, leafy to the top, densely velvety-downy all over, as also the sheaths, with 

 reflexcd soft and often clammy hairs, except a ring below each joint ; leaves likewise 

 velvety all over, lanceolate (' wide), 11 - 13-nerved; panicles spreading, the lateral 

 ones included; spikelets obovate, 1" or l" long, downy; the roundish lower 

 glume scarcely one fourth the length of the 7-nerved upper one. Damp soil, 

 S. New Jersey to Virginia, and southward. Aug. 



16. P. imucifldriiiii, Ell.? Culms upright, at length much branched 

 and reclining (1 - 2 long), roughish ; leaves lanceolate (3' - 5' long by ' - ' wide), 

 rather faintly -nrrvcd, hairy or smooth, fringed on the whole margin or next the 



