POACEAE. 13 



apex long-acuminate, the base narrowed; panicle 1-2 dm. long, 2-3 cm. thick, 

 obtuse, its branches erect or nearly so; spikelets 3-4.5 mm. long, the subtend- 

 ing hairs about twice as long, nearly white. 



Borders of savannas, Andros, New Providence and Eleuthera : Florida ; Cuba ; 

 continental tropical America. SILVER-PLUME GRASS. 



3. SCHIZACHYBIUM Nees, Agrost. Bras. 331. 1829. 



Annual or perennial grasses, the spikelets in spike-like racemes, terminat- 

 ing the culm or its branches. Eachis articulated, the internodes cup-shaped or 

 appendaged, the basal callus barbed. Spikelets in pairs at each node of the 

 rachis, one sessile, the other stalked, the sessile one dorsally compressed, 1-flow- 

 ered, the flower perfect; first scale 2-keeled with infolded margins, the second 

 awnless or bristle-tipped, the third 2-nerved or nerveless, the fourth usually 

 2-cleft, usually bearing a bent awn. Stalked spikelet usually flowerless. 

 Stamens mostly 3. Styles distinct; stigmas plumose. [Greek, cleft-chaff.] 

 Some 40 species, or more, of tropical and subtropical America. Type species: 

 Andropogon ~brevifolius Sw. 



Leaf-blades flat, or sometimes conduplicate when dry, never terete ; racemes glabrous 



or nearly so. 1. 8. semiberbe. 



Leaf-blades terete ; racemes long-hairy. 2. 8. gracile. 



1. Schizachyrium semifoerbe Nees, Agros. Bras. 336. 1829. 



Andropogon setmberbis Kunth, Enum. 1: 489. 1833. 



Perennial; culms glabrous, branched, erect, 6-12 dm. high; leaves glabrous; 

 sheaths compressed, keeled; blades 1-3 dm. long, 2-5 mm. wide; racemes nar- 

 row, 5-8 cm. long, the internodes of the rachis as long as the sessile spikelets 

 or shorter, glabrous or nearly so; sessile spikelets 57 mm. long, the first scale 

 glabrous or with a few short hairs, its infolded margins touching, the third and 

 fourth scales ciliate, the fourth 2-cleft nearly to the base, its awn 12-15 mm. 

 long; .stalked spikelet of one hispidulous scale about 3 mm. long, with an awn 

 about as long. 



Pine-lands, New Providence : Florida ; Cuba ; Hispaniola ; Porto Rico ; Trini- 

 dad ; South America. Recorded by Coker as Andropogon tener Kunth. STIFF 

 BEARD-GRASS. 



2. Schizachyrium gracile (Spreng.) Nash, in Small, PI. SE. U. S. 60. 1903. 



Andropogon gracilis Spreng. /Syst. 1: 284. 1825. 



Perennial, tufted, glabrous, except the inflorescence; culms slender, 

 branched, 2-6 dm. high. Sheaths striate ; leaf -blades 2 dm. long or less, terete, 

 less than 1 mm. in diameter; racemes long-stalked, 3-5 cm. long, the rachis 

 clothed with long silky hairs; sessile spikelet 56 mm. long, the first scale char- 

 taceous with hispidulous keels, the second scale acute, the fourth 2-cleft, bearing 

 an awn 13-20 mm. long; stalked spikelet of one short-awned scale 1-2.5 mm. 

 long. 



Pine-lands and scrub-lands, Abaco, Great Bahama, Andros, New Providence, 

 Eleuthera, Cat Island, North Caicos : Florida ; Jamaica ; Hispaniola ; Porto Rico ; 

 Cuba ; Guadaloupe. SLENDER BEARD-GRASS. 



4. ANDROPOGON L. Sp. PI. 1045. 1753. 



Perennial grasses with usually long narrow leaves, and terminal and axil- 

 lary racemes. Spikelets in pairs at each node of the jointed hairy rachis, one 

 sessile, and perfect, the other with a pedicel and either staminate, empty or 



