Lax Gaping Grass

Panicum laxum Sw. Prodr. 23. 1788
Panicum agrostidiforme Lam. Tab. Encyc. 1: 172. 1791.
Panicum tenuiculme G. Meyer, Fl. Ksseq. 58. 1818.
Panicum leptomerum J. Presl, in Presl, Rel. Haenk. 1: 311. 1830.
Panicum diandrum Kunth, R6v. Gram. 393. 1831.
Panicum ramuliflorum Hochst.; Steud. Syn. Gram. 65. 1854.
Agrostis nigrescens Salzm.; Steud. Syn. Gram. 65. 1854.
Panicum nigrescens Salzm.; Steud. Syn. Gram. 66, as synonym. 1854.
Panicum Agrostis Nees; Doell, in Mart. Fl. Bras. 2 2 : 213, as synonym. 1877.
Panicum laxum pubescens Doell, in Mart. Fl. Bras. 2 2 : 213. 1877.
Panicum pilosum epilosum Fourn. Mex. PI. Gram. 24. 1886.
Plants more or less spreading, often rooting at the nodes of the decumbent base; culms simple or sparingly branching, 40-100 cm. high or more; leaf-sheaths shorter than the elongate internodes, ciliate and hirsute at the juncture with the blade, otherwise glabrous or papillosehirsute toward the summit; ligule fimbriate, about 0.5 mm. long; blades erect or ascending, conduplicate or flat, 10-25 cm. long, 5—15 mm. wide, rarely wider, narrowed to the rounded or subcordate base, glabrous or with a few scattered hairs on the upper surface; panicles oblong in outline, 5-30 cm. long, composed of many slender, raceme-like branches, the lower distant, spreading, sometimes as much as 10 cm. long, the upper ascending; branchlets very short, mostly secund on the lower side of the branches, bearing 2 or 3 spikelets, or a few toward the base of the lower branches 5-10 mm. long; spikelets 1.1-1.5 mm. long, about 0.7 mm. wide and as thick or thicker; first glume one third to half the length of the spikelet, subacute, 1-3-nerved; second glume slightly shorter than the sterile lemma, the latter subtending a palea of nearly equal length, this becoming subrigid at maturity forcing open the spikelet; fruit 1-1.1 mm. long, about 0.5 mm. wide.
Type locality: Jamaica.
Distribution: Mexico and the West Indies to Paraguay.