224 NORTH AMERICAN FLORA [VolumK 17 



the summit; leaf -sheaths longer than the short lower internodes, shorter than the middle and 

 upper ones, papillose-hispid, the hairs ascending; ligule about 2 mm. long; blades erect, or 

 spreading at the apex, 7-30 cm. long, 5-10 mm. wide, scarcely narrowed to the more or less 

 infolding base, flat or folded, sparsely papillose-pilose to nearly glabrous on both surfaces, 

 glaucous on the upper surface; terminal panicles rather long-exserted, those of the branches 

 short-exserted or slightly included at base, 7-20 cm. long, usually scarcely half as wide, the 

 flexuous branches ascending, bearing short, rather spreading branchlets with 1-3 spikelets 

 toward their ends, the whole forming a more evenly flowered panicle than in P. Hallii; spikelets 

 4-4.2 mm. long, about 1.5 mm. wide, narrowly ovate, turgid, acuminate; first glume about half 

 the length of the spikelet, acuminate, 5-nerved, the midnerve scabrous toward the apex; second 

 glume and sterile lemma strongly 7-9-nerved, the midnerves scabrous toward the apex; fruit 



* 



2.3-2.5 mm. long, 1.3-1.5 mm. wide, oval, turgid, obtuse. 



Type locality: Chihuahua, Chihuahua. 

 Distribution: Mexico to Panama. 

 Illustration: Contr. U. S. Nat. Herb. 15: /. 64. 



39. Panicum Ghiesbreghtii Fourn. Mex. PI. Gram. 29. 1886. 



IPanicum Virletii Fourn. Mex. PL Gram. 29. 1886. 



Panicum hirtivaginum Hitchc. Contr. U. S. Nat. Herb. 12: 223. 1909. 



Plants in small tufts, rather robust; culms erect, papillose, ascending-hirsute, 60-80 cm. 

 high, the nodes densely hirsute ; leaf-sheaths mostly longer than the internodes, hirsute like the 

 culms; ligule about 2 mm. long; blades erect or ascending, as much as 60 cm. long and 12 mm. 

 wide, flat, not narrowed to the rounded base, papillose-hirsute on both surfaces or glabrescent; 

 panicles short-exserted, nearly equaled by the upper blades,, 20-30 cm. long, usually less than 

 half as wide, the branches ascending, naked at the base, the branchlets more or less appressed, 

 bearing short-pediceled, approximate, but not crowded spikelets 3 mm. long, 1 mm. wide; 

 first glume half to two thirds the length of the spikelet, acute, 3-5-nerved; second glume and 

 sterile lemma strongly 7-9-nerved; fruit 1.9-2 mm. long, 0.9 mm. wide, elliptic. 



Type locality: Mexico. 



Distribution: Mexico and the West Indies to northern South America. 



Illustrations: Field Columb. Mus. Publ. Bot. 3: 32 (as P. hirticaule); Contr. U. S. Nat. 

 Herb. 15: /. 65. 



40. Panicum hirsutum Sw. PI. Ind. Occ. 173. 1797. 



Plants robust; culms as much as 1 cm. thick and 1.5 meters or more high, simple or sparing- 

 ly branching, glabrous or with a few scattered hairs, the nodes appressed-pubescent ; leaf- 

 sheaths mostly overlapping, hirsute with spreading stiff hairs, these causing mechanical irri- 

 tation to the skin; ligule dense, about 3 mm. long; blades flat, 20-50 cm. long, 20-35 mm. wide, 

 scarcely narrowed to the rounded base, glabrous or with a few hairs toward the base, the mar- 

 gin serrulate; panicles short-exserted or included at base, 20—35 cm. long, 3-12 mm. wide, at 

 first compact, with ascending branches, but becoming diffuse at maturity, the branches widely 

 spreading; spikelets 2-2.2 mm. long, about 0.9 mm. wide, rather turgid, abruptly pointed; 

 first glume scarcely half the length of the spikelet, acute, 3-5-nerved ; second glume and sterile 

 lemma 5-7-nerved; fruit 1.5 mm. long, 0.7 mm. wide, elliptic. 



Type locality: Jamaica. 



Distribution : West Indies and central Mexico to northern South America. 



Illustration: Contr. U. S. Nat. Herb. 15: /. 66. 



41. Panicum maximum Jacq. Coll. 1: 76. 1786. 



Panicum polygamum Sw. Prodr. 24. 1788. 



Panicum laeve I^am. Tab. Kncyc. 1: 172. 1791. 



Panicum jumentorum Pers. Syn. PI. 1: 83. 1805. 



Panicum scaberrimum Lag. Gen. & Sp. Nov. 2. 1816. 



Panicum trichocondylum Steud. Syn. Gram. 74. 1854. 



Panicum praticola Salzm.; Doell, in Mart. Fl. Bras. 2 2 : 203, as synonym. 1877. 



Plants light-green, 1-2.5 meters high, or taller in cultivation, in tufts of few to many culms, 

 from creeping rootstocks ; culms robust, erect or sometimes geniculate and rooting at the lower 

 nodes, glabrous, the nodes usually densely hirsute; leaf-sheaths shorter than the internodes, 

 papillose-hirsute to glabrous-ciliate, usually a dense ring of pubescence at the juncture with 



