Plants annual. Culms 30-100 cm; nodes glabrous. Sheaths
mostly glabrous, margins ciliate distally; ligules 1-2 mm, of hairs; blades
5-15 mm wide, flat, abaxial surfaces scabrous, adaxial surfaces sparsely villous.
Panicles 5-15 cm, tapering to the apices, branches verticillate; rachises
antrorsely rough hispid, without villous hairs; bristles solitary, 4-7
mm, antrorsely or retrorsely scabrous. Spikelets 2-2.3 mm. Lower glumes about
1/3 as long as the spikelets, obtuse, 1(3)-veined; upper glumes nearly
as long as the spikelets; lower paleas about 1/2 as long as the spikelets,
broad; upper lemmas finely and transversely rugose; upper paleas similar
to the upper lemmas. 2n = 36.
Setaria verticilliformis is a European adventive that has been found at
scattered, mostly urban, locations in the United States.