Plants perennial. Culms 50-100 cm; nodes usually glabrous.
Sheaths glabrous or finely pubescent, margins ciliate distally; ligules
of 1 mm hairs; blades 15-20 cm long, 6-12 mm wide, flat or folded, often
finely pubescent on both surfaces. Panicles 15-20 cm, loosely spikelike,
interrupted, attenuate; rachises often villous; branches ascending,
lower branches about 2.5 cm; bristles usually solitary, less than 10 mm,
antrorsely scabrous. Spikelets 2-2.5 mm, ovate-lanceolate. Lower glumes
about 1/2 as long as the spikelets, 3-veined; upper glumes about 2/3 as
long as the spikelets, 5-7-veined; lower lemmas equaling the upper lemmas;
lower paleas as long as the upper paleas, broad; upper lemmas finely
and distinctly transversely rugose. 2n = unknown.
Setaria setosa is native to the West Indies and Mexico. It is probably
a recent introduction to Florida, but appears to be established there. The specimen
from New Jersey was from a ballast dump; the species is not established in that