19 P. latifolium L. Culm mostly erect, 1 to 2f high; lvs. lanceolate, base dilated and cordate-clasping, 3 to 5' by 1, 11 to 13'veined, smoothish; sheaths hirsute at throat; pan. exserted, compound, loose, about 3' long; spikelets oval, obtuse, l 1/2" long, green; lower glume orate, not half a? long as the upper; abortive pales subequal, usually with 3 stamens. - In moist, shady places, U. S. and Can. Jn., Jl. (P. scoparium and nervosum Lam. P. ciliatum Ell., etc.)
20 P. xanthophysum Gray. Culm generally simple, glabrous, 9 to 15' high; lvs. lanceolate, 3 to 6' by 5 to 7", not dilated at the ciliate, clasping base, smooth, 9 to 11-veined; pan. long-exserted, simple, raceme-like, few-flowered; spkl. round-ish-obovate 1 1/2" long; lower glume ovate, 3-veined, acutish, 1/2 as long as the up-per many-veined one; abortive pales oftener with 3 stamens - Dry soils, N. Eng. to Wis. (Lapham) Rare. Jn.
21 P. viscidum Ell. Hoary, with a dense, short, soft, viscid pubescence; culm decumbent, assurgent 2 to if, stout; joints a smooth brown ring; lvs. lance-linear, 3 to 6' by 6 to 16"; sheaths much shorter than the internodes; pan. rather large (4 to 6 long); loose; spkl. light green, 1" long, oval, acutish, lower glume very small, upper pale very small, truncate. - Damp places, N. J. to Ga, (Feay),
22 P. clandestinum L. Culm with short, axillary, appressed branches, 2 to 3f high, rigid, leafy; lvs. 3 to 6' by 1', lanceolate, subcordate at base; sheaths hispid with papillae in the grooves bearing bristly hairs, and enclosing the short lateral panicles; spkl. elliptical, acutish, 1 1/2" long, striate, often purple; upper pale of the neutral fl. obtuse. - Moist woods, Mass. and Mid. States. Jl., Aug.
23 P. microcarpon Muhl., Dark Culm 18 to 30' high, erect, simple, glabrous; joints glabrous; lvs. lanceolate, veined, ciliate at base, undulate and scabrous on the margin, scabrous above, smooth beneath, 6 to 10" wide; sheaths deeply striate, smooth; stip. 0; pan. much branched, nearly smooth; spkl. small, (1/2" long), roundish-obovate, purple, numerous, scarcely pubescent; upper sterile pale minute; fr. shining, biuish white. - .
24 P. Walteri E1l Culm slender, glabrous, erect, 2f; lvs. linear 3 to 6' by 2 to 3", glabrous as well as the open sheaths; spikes thick, dense, 1-sided, alternate (the 2 lower sometimes opposite), 6 to 12" long; spkl. imbricated in 3 rows, broad-ovate; glumes minutely hispid, the lower half as large, upper 3-veined; abortive pales unequal, staminate; fertile fl. roundish. - Damp grounds, Can. to Fla. and La. Jn. - Aug. (Nearly allied to Oplismenus.)
25 P. Aurelianum Hale (MS.). Culm decumbent, geniculate, slender, branched, glabrous; lvs. lanceolate, glabrous, 1 to 2'by 3 to 4", sheaths ciliate; spikes slender, 6 to 12" long, alternate, 1-sided; spkl. ovate, acute; lower glume 1/2 as long as the upper, smooth and 5-veined one; abortive pales equal, staminate; fertile fl. ovate. - Damp soils, about N. Orleans (Hale).
26 P. miliaceum L. Millet. Lvs. lance-linear and sheaths hairy; culm 2 to 3f high; pan. large, open, nodding; spkl. solitary, ovate; gls. acuminate-mucronate, subequal; pales obtuse. - Cultivated, † Turkey.
27 P. Jumentorum Pers. Another cultivated species, from N. Africa. Much valued South. It is tall, stout, smooth. The spikelets are singularly arranged in 2s or 3s, one or two sterile to each fertile. Seeds black.
19. OPLIS'MENUS Beauv. Cock-spur Grass. (Gr. armament, courage; alluding to the stout awns.) Spikelets, etc.
as in Panicum, except that the lower abortive pale (and often the glumes) is prolonged more or less into an awn. - Coarse grasses with the fls. in dense paniculate racemes.
1 O. Crus-galli Kunth. Barn-yard Grass. Terete, smooth, 3 - 4f high; lvs. linear-lanceolate, flat, serrulate, with smooth, striate sheaths and no stipule; pan, simple or apparently so, branches spike-form, compound, alternate and in pairs; rachis hairy and rough; glumes scarcely awned, hispid-bristly; lower abortive palea ending in a rough awn, 6" to 18" long; fertile fl. ovate. - A coarse, weedy grass, introduced into cultivated grounds, barn-yards, etc, common. Aug., Sept § Variable. (Panicum, L.)
β. mutious. Awns very short, or the pale merely subulate-pointed. Common. γ. hispidus. Sheaths very bristly; awns very long.
2 O. hirtellus R. & S. Culm glabrous, decumbent, branched; lvs. lanceolate, flat, 1 to 2' by 2 to 4", with scattered, appressed hairs on the upper surface; sheaths ciliate; pan. of remote, short (6"), dense, alternate spikes, the rachis flex-uous; glumes nearly equal, both awned; lower pale with a stout awn which is much longer than those of the glumes; upper pale minute; fertile fl. lanceolate. - Dry shades, Car. to Ga. and La. Aug. - Oct. (Panicum, L.)
20. SETA'RIA, Beauv. Bristly Fox -tail Grass. (Lat. seta, a bristle.) Spikelets, etc. as in Panicum, but each subtended by a cluster of awn-like bristles (abortive pedicels), forming a sort of bristly involucre. - Fls. in dense, cylindric spikes or spike-like panicles.
§ Bristles of the involucre rough backwards, in pairs, short......................
§ Bristles rough upwards. - Fertile pales strongly rugous crosswise...............
Nos. 2, 3
- Fertile pales smoothish, striate lengthwise............................................
- Fertile pales smoothish, not striate.........................................................
Nos. 5, 6
1 S. verticillata Beauv. Culm smooth, about 2f high; lvs. lance-linear, rough-edged; sheaths smooth, hairy on the margin; spicate pan. composed of short, divided branches in interrupted verticils, 2 - 3' long; bristles of the invol. in pairs, rough backwards, as well as the upper part of the culm; paleae of the roughish-punctate. - Sandy fields, N. Eng. to Ohio, more frequent South. July. §