Plants perennial. Culms 30-70 cm, wiry, much branched distally. Sheaths keeled, margins ciliate distally; collars glabrate; ligules to 1 mm, densely ciliate; blades 5-15 cm long, 2-4 mm wide, flat, scabrous. Panicles 2-6 cm, spikelike, basal portion rarely lobed, tapering distally; rachises scabrous to puberulent; bristles solitary, 3-10 mm. Spikelets 1.9-2.1 mm. Lower glumes about 1/2 as long as the spikelets, 3-veined; upper glumes about 3/4 as long as the spikelets, 5-veined; lower lemmas nearly equaling the upper lemmas, 5-veined; lower paleas rudimentary to 1/2 as long as the upper paleas; upper lemmas finely and transversely rugose; upper paleas narrow. 2n = 36.

Setaria texana grows in shaded habitats on sandy loam soils of the Rio Grande plain of south Texas and northeastern Mexico.