718 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



143. SETARIA Beauv. 

 (Chaetochloa Scribn.) 



Spikelets subtended by one to several bristles (sterile branchlets), falling- 

 free from the bristles, awnless; first glume broad, usually less than half the 

 length of the spikelet, 3- to 5-nerved; second glume and sterile lemma equal, 

 or the glume shorter, several-nerved; fertile lemma coriaceous-indurate, 

 transversely rugose or smooth. Annual or perennial grasses, with narrow 

 terminal panicles, these dense and spikelike or somewhat loose and open. 

 Type species, Setaria viridis. Name from Latin seta, a bristle, alluding to the 

 numerous bristles of the inflorescence. The species are, in general, palatable 

 and nutritious. A few species, especially S. macrostachya, form an appreciable 

 part of the forage on southwestern ranges. Primitive peoples have cultivated 

 S. italica, Italian or foxtail millet, since prehistoric times. The seed has been 

 found in early remains such as those of the Swiss lake dwellings of the stone 

 age. In America this species is used for hay. Another species, S. palmifolia, is 

 cultivated for ornament in greenhouses. 



Bristles below each spikelet numerous, at least more than 5. Panicle dense, cylindric, spike- 

 like. 

 Plants annual; spikelets 3 mm. long; lower floret staminate, the palea well developed. 



1. S. LTJTESCEXS. 



Plants perennial; spikelets 2 to 2.5 mm. long; lower floret neuter, the palea reduced. 



2. S. GEXICULATA. 



Bristles below each spikelet 1 to 3, or, by the abortion of the spikelets, 4 or 6. (See also 

 S.faberii.) 

 Bristles more or less retrorsely scabrous (antrorsely in var. ambigua). 



3. S. VERTICILLATA. 



Bristles antrorsely scabrous only. 

 Plants perennial. 



Spikelets 3 mm. long. 



Blades scabrous „ 4. S. macrosperma. 



Blades villous 5. S. villosissima. 



Spikelets 2 to 2.5 mm. long. 



Blades mostly less than 1 cm. wide, often folded; panicles usually loosely or inter- 

 ruptedly spikelike, the branches usually not more than 1 cm. long. 



6. S. MACROSTACHYA. 



Blades flat, as much as 1.5 cm. wide; panicles tapering from near the base, the 



lower branches as much as 3 cm. long 7. S. scheelei. 



Plants annual. 



Fertile lemma coarsely transversely rugose. 



f Panicle densely cylindric 8. S. corrugata. 



Panicle loosely flowered 9. S. lieb.maxxi. 



Fertile lemma finely cross-lined or nearly smooth. 



Panicle loosely flowered, tapering above 10. S. grisebachii. 



Panicle compactly flowered, sometimes interrupted at base. 



Culms as much as 3 m. tall; bristles 1 to 2 cm. long; fertile lemma smooth or 



nearly so 11. S. magna. 



Culms mostly less than 1 m. tall. 



Panicle cylindric, tapering above, green; spikelets falling entire. 



Spikelets 2 to 2.5 mm. long; bristles 1 to 3 below each spikelet; panicle erect 



or somewhat nodding 12. S. viridis. 



Spikelets 2.8 to 3 mm. long; bristles 3 to 6 below each spikelet; panicle con- 

 spicuously nodding 13. S. faberii. 



Panicle lobed or interrupted, often large and heavy, purple or yellow; fruit 

 deciduous from glumes and sterile lemma 14. S. italica. 



1. Setaria lutescens (Weigel) 



Hubb. Yellow bristlegrass. (Fig. and 1 cm. wide, flat, twisted in a loose 



1094.) Annual, branching at base; spiral, villous toward the base above ; 



culms erect to prostrate, mostly 50 to panicle dense, evenly cylindric, spike- 



100 cm. tall, compressed; sheaths like, yellow at maturity, mostly 5 to 



keeled; blades as much as 25 cm. long 10 cm. long, about 1 cm. thick, the 



