220 NORTH AMERICAN FLORA [VOLUME 17 



26. Panicum hirticaule J. Presl, in Presl, Rel. Haenk. 1: 308. 1830. 



Panicum Jlabellatum Fourn. Bull. Soc. Bot. Fr. 27: 293. 1881. Not P. fldbellatum Steud. 1854. 

 Panicum polygamum hirticaule Fourn. Mex. PI. Gram. 28. 1886. 



Plants erect, simple or nearly so, or sometimes branching and decumbent at base, 15-70 

 cm. high; culms papillose-hispid to glabrous, the nodes spreading-hispid ; leaf-sheaths papillose- 

 hispid, but sometimes sparsely so; blades 5-15 cm. long, 4—13 mm. wide, often cordate at base, 

 sparsely hispid or nearly glabrous, ciliate toward the base; panicles exserted, 5-15 cm. long, 

 scarcely one third the entire height of the plant, rather many-flowered, the branches ascend- 

 ing, the lower usually narrowly so, scabrous but not pilose, bearing rather short and appressed- 

 pediceled spikelets along half to two thirds their length, the glabrous pulvini inconspicuous; 

 spikelets 2.7-3.3 mm. long, 1-1.1 mm. wide (smaller in occasional specimens), lanceolate- 

 fusiform, acuminate, typically reddish-brown; first glume half to three fourths the length of 

 the spikelet, acuminate, the midnerve scabrous toward the apex; second glume slightly longer 

 than the sterile lemma, both much exceeding the fruit, strongly many-nerved, the midnerves 

 scabrous toward the summit, the palea of the sterile floret small, nerveless; fruit 2 mm. long, 

 1 mm. wide, elliptic, a scar sometimes showing on either side at base. 



Type locality: Acapulco, Guerrero. 



Distribution: Texas to southern California, and south through Mexico to northern South 



America; Haiti. 



Illustrations: Bull. U. S. Dep. Agr. Agrost. 17: /. 351; Rep. Mo. Bot. Gard. 10: pi. 19; 

 Contr. U. S. Nat. Herb. 15: /. 46. 



27. Panicum pampinosum Hitchc. & Chase, Contr. U. S. Nat. Herb. 



15: 66. 1910. 



Plants freely branching from the base; culms ascending from a decumbent base, branching 

 at the lower and middle nodes, compressed, glabrous, or sparsely pilose below the panicle, the 

 nodes pubescent; leaf -sheaths loose, papillose-hispid, ciliate; ligule of very stiff hairs 2-3 mm. 

 long; blades 5-12 cm. long, 5-10 mm. wide, flat, scarcely narrowed at the rounded or subcordate 

 base, sparsely pilose above, sparsely hispid beneath, the margin pilose and more or less undu- 

 late; panicles long-exserted, 6-15 cm. long, half to two thirds as wide, the branches solitary, the 

 lower as much as 5-8 cm. long, often bearing a branchlet at base, stiffly ascending, bearing 

 several, mostly short, appressed branchlets with rather crowded, short-pediceled spikelets; 

 spikelets about 4 mm. long, 1.4 mm. wide, very turgid, pointed; first glume more than three 

 fourths the length of the spikelet, pointed; second glume and sterile lemma subequal, exceeding 

 the fruit and pointed beyond it, the sterile palea short; fruit 2.2 mm. long. 1.3 mm. wide, oval, 

 an indistinct scar at the base. 



Type locality: Wilmot, Arizona. 



Distribution: New Mexico and Arizona to Guanajuato. 



Illustration: Contr. U. S. Nat. Herb. IS: /. 48. 



28. Panicum decolorans H. B. K. Nov. Gen. & Sp. 1: 100. 1815. 



Plants tinged with purple, branching from the base; culms ascending or erect, usually 

 from a geniculate base, simple or bearing simple, usually sterile branches from the lower one or 

 two nodes, strongly striate or almost grooved, glabrous to sparsely papillose-hispidulous, the 

 nodes appr essed-pubescent or glabrous ; leaf -sheaths short, but sometimes overlapping on the 

 shortened lower internodes, glabrous to sparsely papillose-hispid, ciliate; ligule membranaceous- 

 fimbriate, hardly 1 mm. long; blades 8-15 cm. long, 7-10 mm. wide, flat, glabrous on both sur- 

 faces or with a few scattered papillae, these with or without short, stiff hairs; panicles finally 

 exserted, 10-18 cm. long, usually not more than one third, but sometimes as much as two thirds 

 as wide, the rather long branches usually narrowly ascending, the short-pediceled spikelets 

 somewhat crowded on approximate, short, appressed branchlets; spikelets 4.5-5.2 mm. long, 

 1.6 mm. wide, pointed; first glume less than half the length of the spikelet, acute; second glume 

 and sterile lemma subequal, exceeding the fruit and pointed beyond it; fruit 2.8-3.2 mm. long, 

 1.5 mm. wide. 



Typb locality: Queretaro, Queretaro. 



Distribution: Central Mexico. 



Illustration: Contr. U. S. Nat. Herb. 15: /. 370. 



