Plants perennial; sometimes forming dense clumps. Culms 20-80 cm, wiry. Sheaths shorter than the internodes, keeled, usually glabrous, rarely sparsely pilose; ligules 0.2-0.6 mm; blades 5-25 cm long, 1-3.5 mm wide, stiff, adaxial surfaces usually glabrous, smooth or scabrous. Panicles 2-6(6.8) cm; rachis internodes 2-4 mm; fascicles 5-13 mm long, 2-4 mm wide, not imbricate, ovoid, glabrous; outer bristles sometimes present, flattened; inner bristles less than 30, 3.2-6 mm long, 0.2-1 mm wide at the base, in more than 1 whorl, fused for at least 1/2 their length into a distinct cupule, diverging at irregular intervals from the cupule, somewhat flattened, spreading, purple-tipped at maturity. Spikelets 1-3 per fascicle, 4-7 mm. Lower glumes 1.4-3.1 mm; upper glumes 3.2-5.4 mm, 3-5-veined; upper lemmas 4-6 mm, 3-5-veined; upper florets 3.9-6.5 mm; anthers 0.9-1.9 mm. Caryopses 1.8-3 mm long, 1-1.5 mm wide, ovoid-elliptic. 2n = 34.

Cenchrus gracillimus grows in sandy soils of open pinelands, wet prairies, and river flatsof the southeastern United States and the West Indies.