Culms 5-40(45) cm, erect or ascending, smooth, glabrous. Sheaths 1-6 cm, uppermost sheath on each culm clearly expanded; ligules 0.2-1 mm, denticulate; blades to 7 cm long, 1.5-2.5 mm wide, scabrous adaxially. Spikes 8-25 cm, rigid, straight or somewhat curved. Spikelets 5-8 mm, slightly longer than the adjacent internodes, alternate, 2-ranked. Glumes ovate-lanceolate; upper glumes glabrous, midveins prominent, apices acute, sometimes mucronate; lower lemmas 4-6 mm; paleas 2-veined; anthers 2-3.5 mm. 2 n = 14, 26, 52.

Hainardia cylindrica is now established in California, along the Gulf coast of Texas and Louisiana, and in northern Baja California, Mexico. It grows in coastal salt marshes and alkaline soils below 300 m.