Part 2, 1912] POACEAE 131 
Pedicellate spikelet staminate or empty, awnless. Stamens 3, very rarely 2. Ovary glabrous, 
or very rarely pilose. Stigmas linear-oblong, commonly equaling the styles. 
Type species, Holcus Sorghum L. 
Branches of the panicle divided ; pubescence of the inflorescence white. 
Rachis of the racemes at length readily disarticulating ; pedicellate spike- 
let usually staminate, equaling the sessile. 1. A. halepensis. 
Rachis of the racemes continuous or tardily disarticulating ; pedicellate 
spikelet usually empty, shorter than the sessile one. 2. H. Sorghum, 
Branches of the panicle simple or nearly so; pubescence of the inflorescence 
brown or purple. 3. H. trichocladus. 
1. Holcus halepensis L. Sp. Pl. 1047. 1753. 
Blumenbachia halepensis Koeler, Descr. Gram. 29. 1802. 
Andropogon halepensis Brot. Fl. Lusit. 1: 89. 1804. 
Sorgum halepense Pers. Syn, Pl. 1: 101. 1805. 
Andropogon avenaceus H.B.K. Nov. Gen. & Sp. 1: 189. 1816. Not A. evenaceus Michx. 1803. 
Andropogon Sorghum halepensts Hack. in DC. Monog. Phan. 6: 501. 1889. 
Smooth and glabrous. Stems 5-15 dm. tall, from a long rootstock; leaf-blades 5 dm. 
long or less, up to 3 cm. wide; panicle 1.5-5 dm. long, oblong to oval, its branches ascending, 
the longer ones 7-14 cm. long; sessile spikelet 4.5-5.5 mm. long, ovate, the outer 2 scales 
densely appressed-pubescent with silky hairs, the first scale 3-toothed at the apex, the readily 
deciduous awn of the fourth scale 1-1.5 cm. long, the spiral column much exserted; pedicellate 
spikelet 5-7 mm. long, lanceolate, the 2 outer scales sparingly pubescent. 
TYPE LOCALITY: Syria. 
DISTRIBUTION : New Jersey to California, and south to Florida, Texas, and Costa Rica, in Ber- 
muda and Cuba, and Saeed throughout warm temperate and tropical regions. 
ILLUSTRATIONS: Vasey, Agr. Grasses U.S. 61. 29; ed. 2. lf. 317; Bull. U.S. Dep. Agr. Agrost. 
17: f. 321; Bull. Tenn. Exp. Sta. 5:f.6,; 7: pl. 4, f 14; Britt. & ‘Brown, Ill. Fl. f. 225, Schreb. 
Beschr. Gras. p/. 18; Host, Gram. Austr. 1: £/. 7; Bull. U. S. Dep. Agr. Bot. 3: £1. 5; Field 
Columb. Mus. Publ. Bot. 3: 21, 7 
2. Holcus Sorghum L. Sp. Pl. 1047. 1753. 
Andropogon Sorghum Brot. Fl. Lusit. 1: 88. 1804. 
Sorgum vulgare Pers. Syn. Pl.1: 101. 1805. 
Andropogon Drummondii Steud. Syn. Gram. 393. 1854. 
Sorgum Sorghum Karst. Deuts. Fl. 367. 1881. 
Andropogon Sorghum sativus Drummondi Hack. in DC. Monog. Phan. 6: 507. 1889. 
Andropogon Sorghum sativus vulgaris Hack. in DC. Monog. Phan. 6: 515. 1889. 
Sorgum Drummondii Nees; (Steud. Syn. Gram. 393, as synonym. 1854) Millsp. & Chase, Field 
Columb. Mus. Publ. Bot. 3: 21. . 1903. 
A tall variable annual, with dense or lax panicle, the rachis of the racemes tardily 
disarticulating, the pedicellate spikelets usually empty, or very rarely staminate, shorter than 
the sessile. Stems up to 1.5 m. tall, simple or branched; leaf-sheaths glabrous or pubescent, 
shorter than the internodes; blades up to 6 dm. long and 1-7 em. wide, flat, undulate on the 
margins, drooping at the apex, long-acuminate; panicle up to 3 dm. long, its branches erect or 
more or less spreading; sessile spikelet ovate-lanceolate, elliptic-lanceolate, or obovate, 5-6 
mum. long, 2.5-3.5 mm. broad, the first scale more or less pubescent, the fourth scale usually 
2-lobed or 2-toothed at the apex, bearing a perfect awn 4-10 mm. long; pedicellate spikelet 
with the pedicel one half as long as the sessile spikelet or less. 
TYPE LOCALITY: India. 
DISTRIBUTION : Widely cultivated in all warm temperate and tropical regions, and often escap- 
ing, An extremely variable grass. 
ILLUSTRATIONS: Host, Gram. Austr. 4: £/.2; Nees, Gen. Fl. Germ. Sorghum I 21-216; Des- 
court. Fl. Ant. £7. 541; Field Columb. Mus. Publ. Bot.'3: 22 if. 
3. Holcus trichocladus (Rupr.) Nash. 
Andropogon trichocladus Rupt.; Hack. in DC, Monog. Phan. 6: 525. 1889. 
Sorgum trichocladum Kuntze, Rev. Gen. 792. 1891. 
Stems 1-1.5 m. tall, densely barbed at the nodes; leaf-sheaths glabrous, except at the 
usually pubescent apex; blades lanceolate-linear, up to 4 dm. long and 1 cm. wide, acuminate, 
softly pubescent on both surfaces; panicle 1-2 dm. long, the smooth flexuous branches in 
4’s-10’s, about equal in length, capillary; racemes of 5-several internodes, pubescent with 
golden-brown hairs, the internodes and pedicels exceeding one half the length of the sessile 
