128 NORTH AMERICAN FLORA [VoLumE 17 
2. Heteropogon contortus (L,.) Beauv.; R. & S. Syst. 
Veg. 2: 836. 1817. 
Andropogon coniortus I. Sp. Pl. 1045. 1753. - 
Heteropogon hirtus Pers. Syn. Pl. 2: 533. 1807. 
Andropogon Allionii H.B.K. Nov. Gen. & Sp. 1: 185. 1816. Not A. AlHonii DC. 1805. 
Andropogon secundus Willd.; Nees, Agrost. Bras. 364. 1829. 
Heteropogon firmus J. Presl, in Presl, Rel. Haenk. 1: 334: 1830. 
Andropogon firmus Kunth, Enum.1: 486. 1833. 
Sorgum contortum Kuntze, Rev. Gen. 791. 1891. 
Perennial. Stems 2-8 dm. tall, rather sparingly branched above; leaf-sheaths smooth, 
even on the keel; blades 2 dm. long or less, 3-7 mm. wide; racemes 4-7 cm. long, exserted 
or included at the base, the peduncles hispidulous, the internodes between the upper spikelets. 
densely pubescent with long nearly appressed chestnut-brown hairs; pistillate sessile spikelet 
8-10 mm. long, including the brown-barbed callus which is about 3 mm. long, the awn 4.5-12 
cm. long; pedicellate spikelet about 1 cm. long, empty or staminate, the first scale acute, 
papillose-hispid with long hairs toward the summit and near the margins. 
TYPE LOCALITY: India. 
DISTRIBUTION : Texas to Arizona and Honduras, and widely distributed in warm temperate 
and tropical regions generally. 
ILLUSTRATIONS: Bull. U. S. Dep. Agr. Agrost.17: f. 322; All. Fl. Ped. pl. 91, f.4; Nees, 
Gen. Fl. Germ. Heleropozon ; Beauv. Agrost. pl. 23, f. 8 (as Heteropogon gilaber),; Bull.vU. S. 
Dep. Agr. Bot. 121: pl. 16. : 
25. SORGHASTRUM Nash, in Britton, Man. 71. 1901. 
Poranthera Raf. Bull. Bot. Seringe 221. 1830. Not Poranthera Rudge, 1811. 
Usually tall perennial grasses, with simple stems, flat leaf-blades, and terminal decom- 
pound panicles, with the primary branches usually solitary, or in pairs, and branched from the 
base, hence appearing as if whorled. Spikelets single and sessile, or rarely 2, the second 
rudimentary, pedicellate. Sessile spikelet dorsally compressed, of 4 scales, the 2 outer indu- 
rated, often hairy, the third and fourth scales hyaline, the latter awned, the awn usually perfect, 
rarely imperfect. Pedicellate spikelet wanting, or very rarely present as a minute rudiment, 
usually only the hairy pedicels present. Stamens 3. Styles distinct. Stigmas plumose. 
Type species, Andropogon avenaceus Michx. 
Awn imperfect, or if loosely spiral at the base the exserted portion not longer 
than the spikelet. 1. S. setosum. 
Awn perfect, a plurispiral well developed column at the base, the exserted 
portion longer than the spikelet. 
Awn three times as long as the spikelet or less, the column straight, rarely 
geniculate. 
Panicles small, the branches with a long naked base; spikelets few, at 
the end of the branches or their divisions ; innovations with leaf-blades 
3-6 cm. long. 2. S. nudipes. 
Panicles ample; spikelets numerous; innovations with elongate leaf- 
blades. 
Spikelets 4.5-5 mm. long. 3. S. stipoides. 
Spikelets 6-8 mm. long. 4. S. nutans. 
Awn 4-5 times as long as the spikelet, the column distinctly geniculate. 
Spikelets 4 mm. long. 5. S. incompletum. 
Spikelets 6-7 mm. long. 
Peduncles straight or nearly so below the spikelets which are usually 
a deep chestnut-brown when mature. 6. S. Eliiottit. 
Peduncles strongly recurved or coiled below the spikelets which are 
usually pale-brown when mature. 7. S. secundum. 
1. Sorghastrum setosum (Griseb.) Hitche. Contr. U. S. Nat. 
Herb. 12: 195. 1909. 
Andropogon setosus Griseb. Cat. Pl. Cub, 235. 1866. 
Andropogon Francavillanus Fourn. Mex. Pl. Gram. 56, 1881. 
Sorgum nutans micranthum genuinum Hack. in Mart. Fl. Bras. 23: 274. 1883. 
Sorgum nutans micranthum submuticum Hack. in Mart. Fl. Bras. 28: 275, 1883. 
Andropogon agrostoides Speg. Anal. Soc. Ci. Argent. 16: 136. 1883. 
Andropogon nutans agrostoides Hack. in DC, Monog. Phan. 6: 529, 1889. 
Andropogon nutans submuticus Hack. in DC. Monog. Phan. 6: 529. 1889. 
Sorghastrum Francavillanum Hitche. Contr. U. S. Nat. Herb. 12: 195, 1909. 
Sorghastrum agrostoides Hitch. Bot. Gaz. 51: 300. 1911. 
