106 POACEAE 
Panicle usually 1-3 cm. thick: bristles usually purple: spikelets 
2.5-3 mm, long. 9. C. Italica. 
Flowering scale shining, very hard in fruit, smooth : plants usually 
2-4 m. tall. 10. C. magna. 
** Panicle slender, loose, narrow, often interrupted below. 
Spikelets about 3 mm. long. 15. C. villosissima. 
Spikelets about 2 mm. long. 16. C. Grisebachii. 
b. Second scale manifestly shorter than the flowering scale. 
Spikelets less than 3 mm. long. 
Panicle loose, often interrupted below, usually narrowed at thesummit. 
Spikelets elliptie to ovate. 
Panicle long-attenuate at the a 
es 18. C. caudata. 
Panicle narrowed at the apex, but not long-attenuate. 
Leaf-blades 1 em. wide or less : stems usually slender. 16. C. Grisebachii. 
Leaf-blades 1.5-2 em. wide: stems usually stout. 17. C. polystachya. 
Spikelets hemispheric. 13. €. macrostachya. 
Panicle dense, of the same diameter throughout. 
Flowering scale very coarsely undulate-rugose : panicles with many 
bristles. il. C. corrugata. 
Flowering scale finely transverse-rugose: panicles with rather few ; 
bristles. 12. €. composita. 
Spikelets 3 mm. long or more. 
Panicle dense, of equal diameter throughout, 1 em. thick or less, ex- 
clusive of the bristles. 12. C. composita. 
Panicle loose, narrowed at the summit, 2-4 em. in diameter, exclusive 
of the bristles. 
Leaf-blades 1-2 em. wide, glabrous. 14. €. macrosperma. 
Leaf-blades 6-8 mm. wide, pubescent on both surfaces with spread- : 
ing hairs. 15. C. villosissima. 
1. Chaetochloa glaüca (L.) Scribn. Annual. Stems tufted, 3-12 dm. tall, branch- 
ing at the base : leaf-sheaths glabrous, loose, compressed ; blades 1.5 dm. long or less, 4-8 
mm. wide, glaucous, at least the lower ones pilose near the base on the upper surface: ra- 
cemes dense, about 1 cm. in diameter, the rachis pubescent, 2-10 cm. long: spikelets 
broadly ovoid, 3 mm. long and 2 mm. wide, the acute flowering scale striate, coarsely 
transversely rugose. [Setaria glauca Beauv. ] 
In cultivated grounds and waste places nearly throughout North America. Naturalized from 
Europe. Summerand fall. : 
2. Chaetochloa imbérbis (Poir.) Scribn. Perennial. Stems tufted, 3-7 dm. tall, 
from rootstocks, slender, compressed, rough below the raceme : leaf-sheaths glabrous, com- 
pressed ; blades 1-3 dm. long, 3-7 mm. wide, the upper surface often with a few long hairs 
at the base : racemes dense, spike-like, 2-5 cm. long, nearly 1 cm. in diameter, exclusive 
of the bristles, the rachis pubescent : bristles 5-10 mm. long: spikelets ovoid, acute, 2-2.5 
mm. long, the flowering scale acute, striate, finely transversely rugose. [Setaria laevigata 
Chapm. in part. ] 
_ In moist soil, New Jersey, Kansas and Missouri to Florida and Texas. Also in tropical America. 
Spring to fall. 
3 Chaetochloa versicolor Bicknell. Perennial. Stems 6-12 dm. long, ascending : 
leaf-sheaths compressed, keeled, smooth and glabrous ; blades long and narrow, 1-3.5 dm. 
long, 2-6 mm. wide, pale green or glaucous, glabrous: spike-like raceme long-exserted, 
rather slender, 2-7 cm. long, about 1.5 em. in diameter : bristles in two nearly equal clus- 
ters of 5 each, very slender, 6-10 mm. long: spikelets usually single, about 2.5 mm. long 
and 1.25 mm. wide, the first and second scales 3-nerved, the fourth scale purple-tipped. 
[ Panicum laevigatum Ell., not Lam. Setaria laevigata Chapm. in part.] 
Along borders of salt or brackish marshes, Massachusetts to Florida. Summer and fall. 
4. Chaetochloa occidentalis Nash. Perennial. Stems from a stout branching root- 
stock, 3-8 dm. tall: leaf-sheaths compressed, keeled, smooth and glabrous; blades erect, 
firm, 1.5 dm. long or less, 5-7 mm. wide, glabrous: spike-like racemes 3-5 cm. long, I, 
2 cm. in diameter: bristles green: spikelets a little less than 3 mm. long, the flowering 
scale strongly transversely rugose, elliptic. 
In meadows, Kansas and the Indian Territory. Summer. 
5. Chaetochloa purpurascens (H.B.K.) Scribn. & Mer. Perennial. Stems 1-6 
dm. tall, slender, branching, from rootstocks: leaf-sheaths loose, striate, glabrous ; blades 
5-10 cm. long, 4-6 mm. wide, rough on both surfaces : racemes 1-5 em. long, about 5 mm. 
in diameter, the rachis pubescent : bristles 5-10, 3-8 mm. long, often barely exceeding the 
spikelets : spikelets ovoid, acute, 2 mm. long, the flowering scale acute, transversely ru- 
gose. 
In dry places, Texas. Also in tropical America. Spring to fall. 
6. Chaetochloa gracilis (H.B.K.) Scribn. & Mer. Perennial. Stems erect, 3-7 
dm. tall, slender, cylindric, simple, or somewhat branched at the base : leaf-sheaths loose; 
glabrous ; blades involute-setaceous, 2 dm. long or less, 1-3 mm. wide: racemes dense, de 
6 cm. long, 3-5 mm. in diameter: bristles 5-8, very short, equalling or twice -as long as 
