POACEAE. 23 



short bristle: spikelets nearly sessile, about 2 mm. long, in 2 rows, obovoid, 

 glabrous, the first scale obtuse, about one-half as long as the whole spikelet, 

 the second scale 7-nerved, the fourth scale transversely wrinkled. 



Scrub-lands and along marshes. New Providence, Rose Island, Great Exuma : 

 southern Florida. Chapman's Panic-grass. 



8. Panicum laxum Sw. Prodr. 23. 1788. 



Panicum agrostidiforme Lam. Tabl. Encycl. 1: 172. 1791. 

 Panicum tenuiculmum Meyer, Prim. Fl. Esseq. 58. 1818. 



'Culms simple or little branched, often decumbent and rooting at the lower 

 nodes, 4-12 dm. high. Sheaths hirsute above, otherwise glabrous; leaves 1-2.5 

 dm. long, 4-15 mm. wide, glabrous, or sparingly pubescent on the upper side; 

 panicles 0.5-3 dm. long, with many, slender spike-like branches, the lower 

 branches spreading, the ultimate branchlets mostly secund; spikelets 1-1.5 

 mm. long, about 0.7 mm. wide, short-stalked; first scale 1-3-nerved, about one- 

 third the length of the whole spikelet, the second somewhat shorter than the 

 third. 



Turks Islands : nearly throughout tropical America. Red-top Panic-grass. 



9. Panicum tenerum Beyr. ; Trin. Mem. Acad. St. Petersb. VI 1 : 341. 1834. 



Culms slender, stiff, tufted, glabrous, 4-9 dm. high. Sheaths glabrous, or 

 the lower softly pubescent; leaf blades 4-15 em. long, 2-4 mm. wide, or the 

 upper much smaller, erect, somewhat involute in drying, somewhat pubescent, 

 at least toward the base; panicles solitary and terminal, 3-8 cm. long, or also 

 a few smaller ones lateral; spikelets 2-2.8 mm. long, about 1 mm. wide, short- 

 stalked, rather crowded; first scale about one-half the length of the whole 

 spikelet, 1-nerved, the second and third 5-7-nerved. 



Open places in pine and scrublands, Andros and New Providence : Georgia 

 and Florida to Texas ; Cuba ; Porto Rico. Slender Panic-grass. 



10. Panicum condensum Nash, in Small, Fl. SE. U. S. 93. 1903. 



Culms tufted, branched, 0.6-1 m. tall, the basal sheaths compressed and 

 keeled. Leaves 2-4 dm. long, 6-8 mm. wide, erect or nearly so; panicles large, 

 dense, oblong, 1-2.5 dm. long, their branches erect; spikelets numerous, about 

 2.3 mm. long, acute, glabrous; first scale acuminate, about one-half the length 

 of the whole spikelet; second and third scales acuminate. 



Fresh water swamps and wet places, Andros, New Providence, Acklin's Island 

 and Cat Island : New Jersey to Florida and Texas ; Cuba ; Porto Rico ; Guada- 

 loupe ; Jamaica ; Mexico. Dense Panic-grass. 



11. Panicum diffusum Sw. Prodr. 23. 1788. 



Perennial; culms tufted, spreading or ascending, simple or little branched, 

 glabrous with pubescent nodes, 2-5 dm. high. Sheaths striate, glabrous or 

 pubescent; leaf -blades 2 dm. long or less, 1-3 mm. wide, sparingly pubescent; 

 panicles 5-10 cm. long, open, the branches filiform ; spikelets few, near the 

 ends of the panicle-branches, short-stalked, about 2 mm. long and 1 mm. wide; 

 first scale acute, about one-half as long as the spikelet; second and third scales 

 7-9-nerved. 



Coppice, New Providence : Jamaica ; Cuba to St. Thomas, Tortola and Mar- 

 tinique, Diffuse Panic-grass. 



12. Panicum Ghiesbreghtii Fourn. Mex. PI. 2: 29. 1886. 



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



Perennial; culms erect, tufted, rather stout, 6-8 dm. high, the nodes 

 hirsute. Sheaths hirsute; leaf -blades flat, up to 6 dm. long and 12 mm. wide, 

 hirsute or glabrate ; panicle 2-3 dm. long, its branches ascending; spikelet3 

 numerous, short-stalked, about 3 mm. long and 1 mm. wide; first scale acute, 



