1912. 



Part 3, 1915] POACEAB 235 



68. Panicum boliviense Hack. Repert. Sp. Nov. 11: 19. 



Plants perennial," with long decumbent or creeping bases, rooting and branching at the 

 lower nodes; flowering culms ascending, 0.5-1.5 meters high, glabrous, the nodes glabrous; 

 leaf-sheaths short, glabrous below, usually hirsute toward the summit, especially at the juncture 

 with the blade, the margins ciliate; ligule a ciliate membrane about 0.5 mm. long; blades flat, 

 8-15 cm. long, 1-2 cm. wide, gradually narrowed from the cordate-clasping base to an acumi- 

 nate apex, ciliate at base, otherwise glabrous, obscurely cross-nerved between the veins, the 

 margins scabrous; panicles usually short-exserted, 10-25 cm. long, one third to one half as wide, 

 the solitary or fascicled branches increasingly approximate toward the summit of the slender 

 angled scabrous axis, usually pilose in the axils, the lowermost branch solitary and remote, 

 all but the uppermost compound, the branchlets somewhat spike-like, rather distant, usually 

 along the lower side of the rachis, the axils pilose; spikelets subsessile, clustered, 1.5-1.6 mm. 

 long, about 0.7 mm. wide, turgid, the first glume nearly half the length of the spikelet, the 

 second glume and sterile lemma equal, the sterile lemma somewat inflated, subtending a mem- 

 branaceous palea; fruit 1.4 mm. long, 0.6 mm. wide, subacute. 



Type locality: Antahuacana, Bolivia. 

 Distribution: Cuba; southern Mexico to Paraguay. 

 Illustration: Contr. U. S. Nat. Herb. 17:/. 73. 



P 



69. 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 papillose- 

 hirsute 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. 



Illustrations: Trin. Ic. pi. 215; Kunth, R£v. Gram. pi. 110; Contr. U. S. Nat. Herb. 15: /. 109. 



70. Panicum Stevensianum Hitchc. & Chase, Contr. U. S. Nat. 



Herb. 17:498. 1915. 



Plants perennial, tufted, glabrous throughout; culms compressed, 30-60 cm. long, 

 spreading, prostrate, rooting at the nodes, the flowering ends and the branches ascending; 

 leaf -sheaths loose, much shorter than the internodes, compressed, keeled, ciliate on the over- 

 lapping margin; ligule a delicate membrane about 0.5 mm. long; blades flat, rather firm, more 

 or less spreading, 4-10 cm. long, 5-10 mm. wide, tapering from a little above the sparsely 

 truncate-cordate base to an acuminate apex; panicles terminal on the culm and branches, short- 

 exserted, 6-10 cm. long, narrow, consisting of several appressed or ascending spike-like branches 

 along an angled axis, the lower branches somewhat remote, 1.5-3 cm. long, usually longer 



