This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol1", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Culms generally erect, 2°-3° tall, simple, smooth. Sheaths smooth, glabrous, longer than the internodes; ligule none; blades 5'-8' long, 1/2'-1' wide, long-acuminate, smooth, cordate-clasping and sparingly ciliate at the base; panicle 3'-8' long, elliptic, longer than broad; branches slender, ascending; spikelets 3/4" long, obovoid to nearly spherical, numerous; first scale minute, second and third about equal, 7-nerved, puberulent, the fourth white and shining; palet of third scale usually empty.
Smooth and glabrous. Culms coarsely striate, finally branched, tufted, slender, erect, rigid, 4'-8' tall; sheaths less than one-half as long as the internodes; ligule a ring of short hairs; blades longer than the sheaths, those on the culm up to 1 1/4 long, the basal longer, 3/4"-1 1/2" wide, erect, acuminate, 5-7-nerved; panicle 3/4'-1 1/4' long, its branches spreading or ascending; spikelets one-half as long as the pedicels, or less, obovoid, obtuse, 3/4" long, the first scale one-third as long as the spikelet, the second and third scales 7-nerved, densely pubescent with spreading hairs.
Moist sand in the pine barrens, southern New Jersey to Florida and Mississippi. May-July.
Panicum tenue Muhl. Gram. 118. 1817.
P. albomarginatum Nash, Bull. Torr. Club, 24: 40. 1897.
Glabrous, excepting the spikelets. Culms densely tufted, 8'-16' tall, finally branched toward the base, the upper part of the culm naked; leaves usually 2; sheaths much shorter than the internodes; blades erect, thick, stiff, lanceolate, with a prominent white thick margin, usually 1 1/2' long or less, rarely longer, 1"-3 1/2" wide; panicle 3/4'-l 1/2' long, broadly ovate, open; spikelets elliptic, less than 3/4" long and about 1/2 as wide, pubescent with short spreading hairs.
In pine lands, Dismal Swamp, Virginia, to Florida and Louisiana; also in Cuba. June and July.
Panicum dichotomum L. Sp. PI. 58. 1753.
P. barbulatum Michx. Fl. Bor. Am. 1: 49. 1803.
Smooth and glabrous, or the lower nodes barbed. Culms erect, i°-2° tall, at first simple, later profusely dichotomously branched at about the middle; blades light green, widely spreading, generally much narrowed toward the base, the primary ones distant, 2'-3' long, 2"-3" wide, those of the branches 1' long or less, 1/2"-1" wide, sometimes involute; primary panicle usually long-exserted, 1'-2' long; branches lax, spreading, bearing few spikelets; secondary panicles smaller, not exceeding the leaves, their brandies with very few spikelets; spikelets about 1" long, ellipsoid, glabrous.
In woodlands and thickets, New Brunswick to Michigan, Florida and Texas. May-Aug.