632 GRAMINE^E. (GRASS FAMILY.) 



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

 the margins, strongly 9-ll-nerved ; panicle long-peduncled, very simple, the 

 appressed branches bearing a few roundish-obovate spikelets (about \%' long) ; 

 lower glume ovate, acutish, J - - the length of the 9-nerved second. Dry 

 sandy soil, Maine to Penn., Wise., Iowa, and northward; rare. June. Yel- 

 lowish-green ; spikelets minutely downy ; sterile flower sometimes staminate. 



12. P. Iatif61ium, L. Culm (1-2 high) smooth; the joints and 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 ; lower glume ovate, not half the length of 

 the many-nerved second ; sterile flower often (not always) with 3 stamens. 

 Moist thickets ; common. June - Aug. 



13. P. clandestinum, L. (PI. 13, fig. 6, 7.) Culm rigid (1-3 high), 

 very leafy to -the top, at length producing appressed branches, the joints naked ; 

 sheaths rough with papillae, bearing very stiff and spreading bristly hairs ; leaves 

 oblong-lanceolate from a heart-clasping base, very taper-pointed ; lateral and 

 usually also the terminal panicle more or less enclosed in the sheaths, or with 

 the terminal one at length long-peduncled; otherwise resembling n. 12; 

 but the spikelets more ovoid, often smooth ; the lower flower (always ? ) neutral. 

 Low thickets and river-banks, N. Eng. to Mich., Mo., and southward. 

 June - Sept. 



14. P. viscidum, Ell. Culms stout, upright or ascending, at length 

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

 sheaths, with reflexed soft and often clammy hairs, except a ring below each 

 joint; leaves likewise velvety, lanceolate (-' wide), 11 -13-nerved ; panicle 

 spreading, the lateral ones included ; spikelets obovate, 1 or 1|" long, downy ; 

 the roundish lower glume scarcely one fourth the length of the 7-nerved sec- 

 ond one. Damp soil, N. J. to Va., and southward. Aug. 



15. P. SCOparium, Lam. Culms upright, at length much branched and 

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

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

 the base with long and stiff spreading hairs, the sheaths bristly throughout with 

 similar hairs ; panicle open, nearly simple, bearing few tumid-obovate hairy or 

 smoothish spikelets about 1|" long ; lower glume roundish, about half or a 

 quarter of the length of the upper one. (P. pauciflorum, Ell.) Wet mead- 

 ows and copses, E. Mass, to Minn., west and southward. June, July. 



16. P. commutatum, Schultes. Rather slender, erect, 1-2 high, 

 nearly glabrous; leaves lanceolate, acuminate (3-6' long), the margins to* 

 ward the base and the sheaths sparsely ciliate ; panicle spreading, often short- 

 peduncled ; spikelets scattered, glabrous, oblong, acutish, little more than 1" 

 long ; lower glume ovate, often acute. ; N. Y. to Fla. A frequent variety 

 with smaller spikelets (not 1" long) approaches the next, and has also been 

 confused with P. dichotomum. Ont. to Va. and southward. 



= = Spikelets less than \" long. 



17. P. nitidum, Michx. (Lam.?) Eesembles the last; leaves rather 

 thick and the principal nerves very obscure or none except at the base ; pan- 



