Plants cespitose. Culms 60-120 cm, compressed-keeled. Sheathscompressed-keeled; ligules 0.5-1 mm. Rames 3-9.5 cm; rachisesdistinctly indented adjacent to the sessile spikelets. Sessile spikelets3-4 mm; lower glumes transversely rugose; upper lemmas and paleas 2-3 mm. Pedicellate spikelets 1-3 mm. Caryopses about 2 mm, broadly ellipsoid. 2n = unknown.
Coelorachis rugosa is endemic to the southeastern United States. It grows in moist to wet areas in prairies, bogs, and pine woods, especially flatwoods and savannahs.