112 NORTH AMERICAN FLORA [VoLuME 17 
Rachis-internodes smooth; pedicellate spikelet stami- 
nate. 
Sessile spikelet hispidulous on the intercarinal 
space; hairs of the rachis-internodes 2mm. long or . 
less. 26. A. provincialis. 
Sessile spikelet, except the nerves toward the summit 
of the first scale, with the intercarinal space 
glabrous; hairs of the rachis-internodes 3-4 mm. 
long, usually yellow. 27. A. chrysocomus. 
Rachis-internodes strongly hispidulous; pedicellate , ‘ 
spikelet perfect. 28. A. fennesseensis. 
Awn imperfect, rarely a little spiral at the base; plants . 
usually with long horizontal rootstocks. A. Halli, 
Internodes glabrous, or with a few weak crimped hairs. 30. A. paucipilus. 
Sessile spikelet of the lower pair or 2-several pairs differing from those 
above, staminate or empty, awnless. 
Fourth scale of each perfect sessile spikelet stipe-like, the blade 
wanting; racemes usually several together, sometimes 1 or 2; 
sessile and pedicellate spikelets resembling each other. 
Apex of the stem below the inflorescence glabrous; sessile spike- . 
let about 3 mm. long. 31. A. cavricosus, 
Apex of the stem below the inflorescence softly pubescent; ses- . 
sile spikelet 4-5 mm. long. 32. A. nodosus. 
Fourth scale of each perfect sessile spikelet linear, the blade present, 
usually bifid at the apex; racemes always in pairs; pedicellate 
spikelet unlike the sessile one. 
Awns imperfect, glabrous; first scale of the sessile spikelet 
manifestly 2-keeled, the keels winged. 
First scale of the sessile spikelet broadly lanceolate, the in- 
tercarinal space flat and 2-4-nerved. 33. A. Nardus. 
First scale of the sessile spikelet lanceolate, the intercarinal 
space deeply depressed at the base, nerveless. 34. A. ceriferus. 
Awns perfect, the column manifestly hispid; first scale of the 
sessile spikelet not 2-keeled, or only so at the apex. 
Spikelets long-hairy; sessile spikelet with the callus very 
short or almost wanting, obtuse, shortly barbed, the first 
scale not sulcate. 35. A. hirtus. 
Spikelets glabrous, or merely hispidulous toward the apex ; 
sessile spikelet with the long acute or pungent callus 
long-barbed, the first scale sulcate. 
Perfect sessile spikelet with a callus 1-1.5 mm. long, the 
awns 2-3 cm. long; internodes of the rachis setiferous. 36. A. bracteatus. 
Perfect sessile spikelet with a callus 4mm. long, the awns 
about 5 cm. long; internodes of the rachis not setiferous. 37. A. Ruprechii. 
1. Andropogon spathiflorus (Nees) Kunth, Enum. 1: 496. 1833. 
? Andropogon virgatus Desv.; Hamilt. Prodr. 9. 1825. 
Hypogynium spathifiorum Nees, Agrost. Bras. 366. 1829. 
? Anatherum virgatum Desv. Opusce. 71. 1831. 
Andropogon inermis Steud. Syn. Gram. 390. 1854. 
Anatherum spathifiorum Griseb. Cat. Pl. Cub. 236. 1866. 
Anatherum inerme Griseb. Cat. Pl. Cub. 236. 1866. 
Andropogon spathifiorus inermis Hack. in DC. Monog. Phan. 6: 398. 1889. 
Sorgum spathifiorum Kuntze, Rev. Gen. 792. 1891. 
A densely tufted perennial with intravaginal innovations. Stems up to 1 m. tall, simple 
below, much-branched above; leaf-sheaths keeled, compressed; blades of the innovations up 
to 4 dm. long, 1.5~2 mm. wide, those of the stem a little shorter and broader, glabrous or 
ciliate at the base; spathes acute, 1-1.5 cm. long, scarious, glabrous, brown, usually 2-3 times 
aslong as the slender puberulous peduncle of the raceme; spike-like racemes dense, 6-13 mm. 
long, the rachis straight, the internodes and pedicels about one third as long as the sessile spike- 
lets, glabrous; sessile spikelet 2.5-3.5 mm. long, linear-lanceolate, the first scale with narrowly 
infolded margins and aculeate keels, nerveless, excepting the keels, flat on the back, the second 
scale 1-nerved, the third scale shorter than the first, acute, 1-nerved, ciliolate, the fourth scale 
2-toothed, awnless, or merely mucronate between the teeth, the flower pistillate with 3 rudi- 
mentary stamens; pedicellate spikelet equaling the sessile one, lanceolate, strongly colored, 
the first scale very acute, 3-nerved, the fourth scale entire, awnless, the 3 stamens perfect. 
TYPE LOCALITY: In plains, behind Ypanema, Sao Paulo, Brazil. 
DISTRIBUTION : Cuba; Haiti; Porto Rico ; Costa Rica; also in tropical South America. 
ILLUSTRATION: Mart. Fl. Bras. 23: pl. 68, f. Z 
