Part 3, 1915] POACEAK 



225 



the blade; ligule 4-6 mm. long, stiffly and densely ciliate from a membranaceous base; blades 

 erect or ascending, flat, 30-75 cm. long, 1-3.5 cm. wide, very scabrous on the margin, otherwise 

 glabrous, or hirsute on the upper surface at the base; panicles finally long-exserted, 20-50 cm. 

 long, usually about one third as wide, densely flowered, the long, rather stiff branches ascending, 

 naked at the base, the lower in whorls, the axils pilose, the branchlets short, appressed, bearing 

 more or less clustered, short-pediceled spikelets; spikelets 3-3.3 mm. long, 1-1.1 mm. wide, 

 and about as thick, oblong- ellipsoid, glabrous, somewhat shining, faintly nerved; first glume 

 about one third the length of the spikelet, obtuse; second glume and sterile lemma subequal, 

 slightly exceeding the fruit, thin in texture, the lemma inclosing a staminate flower; fruit 2.3-2.5 

 mm. long, about 1 mm. wide, elliptic, transversely rugose, minutely puberulent at the apex. 



Type locality: Guadeloupe. 



Distribution: Introduced in America, from Florida, Mexico, and the West Indies to tropical 

 South America; also in the tropical parts of the Old World. 



Illustrations: Vasey, Agr. Grasses U. S. pi. 5; ed. 2. pi. 9; Field Columb. Mus. Publ. Bot. 3: 

 33; Bull. U. S. Dep. Agr. Agrost. 14: f.'64; Contr. U. S. Nat. Herb. 15: /. 67. 



42. Panicum plenum Hitchc. & Chase, Contr. U. S. Nat. Herb. 15: 80. 



1910. 



Plants mostly in large clumps, 1-2 meters high, from a stout rpotstock, mostly glaucous ; 

 culms robust, compressed, glabrous, usually ■ decumbent at base, sometimes branching at the 

 lower nodes ; leaf-sheaths overlapping on the short lower internodes, shorter than the upper, gla- 

 brous, or the lower sometimes pubescent toward the summit, more or less keeled; ligule densely 

 ciliate, about 2 mm. long; blades erect or ascending, or the lower spreading and soon deciduous, 



M 



flat, 20-35 cm. long, 7-17 mm. wide, glabrous on both surfaces or rarely sparsely pilose on either 

 surface toward the base, the upper surface scarcely scabrous; panicles 20-50 cm. long, about 

 two thirds as wide, the slender branches somewhat spreading, the general appearance much 

 like that of P. bulbosum n but proportionately wider, the main axis nearly smooth; spikelets 3-3.4 

 mm. long, 1.2 mm. wide, oblong-elliptic, glabrous, rather strongly nerved; first glume scarcely 

 half the length of the spikelet or less, subacute, 3-nerved ; second glume and sterile lemma sub- 

 equal, scarcely exceeding the fruit, the palea of the sterile floret about as long as its lemma; 

 fruit 2.9-3 mm. long, 1 mm. wide, elliptic, acute, only very obscurely rugose, minutely puberu- 

 lent at the apex. 



Type locality: Near Silver City, New Mexico. 

 Distribution : Texas to Arizona and central Mexico. 

 Illustration: Contr. XI. S. Nat. Herb. 15: /. 69. 



43. Panicum bulbosum H. B. K. Nov. Gen. & Sp. 1: 99. 1815. 



Panicum avenaceum H. B. K. Nov. Gen. & Sp. 1: 99. 1815. 

 Panicum gongylodes Jacq. f. Bclog. Gram. 30. 1815. 

 Panicum confusum Trin.; Nees, Agrost. Bras. 174, as synonym. 1829. 

 Panicum nodosum Willd.; Steud. Nom. ed. 2. 2: 260, as synonym. 1841. 

 Panicum maximum gongylodes Doell, in Mart. Fl. Bras. 2 2 : 203. 1877. 

 Panicum maximum bulbosum Vasey, in Rothr. Bot. Wheeler's Surv. 295. 1878. 

 Panicum polygamum gongylodes Fourn. Mex. PL Gram. 28. 1886. 

 Panicum bulbosum avenaceum Beal, Grasses N. Am. 2: 132. 1896. 



Plants in tufts of few to several culms, 1-2 meters high ; culms robust, erect, glabrous, the 

 lowest internode thickened into a hard, corm-like base, 1-2 cm. thick, budding at the base, 

 sometimes one or more corms of previous years attached; leaf-sheaths shorter than the inter- 

 nodes, glabrous or scabrous to pilose toward the summit, the lower often appressed-pubescent 

 at base; ligule scarcely 1 mm. long; blades erect or ascending, flat, 25-60 cm. long, 3-12 mm. 

 wide, scabrous on the upper surface, often pilose toward the base, glabrous beneath; panicles 

 long-exserted, 20-50 cm. long, usually about half as wide, rather many-flowered, the slender, 

 flexuous branches ascending or somewhat spreading, solitary or fascicled, naked at the base, 

 the branchlets 1 to several cm. long, bearing scarcely clustered, rather short-pediceled spike- 

 lets, the axes and pedicels very scabrous; spikelets 3.5-4.2 mm. long, 1.2-1.4 mm. wide, slightly 

 pointed, more strongly nerved than in P. maximum, glabrous, commonly purplish; first glume 

 half to two thirds the length of the spikelet, bluntly pointed, 3-nerved; second glume shorter 

 than the fruit and sterile lemma, the latter rarely inclosing a staminate flower; fruit 3.2-4 mm. 



