Plants perennial; cespitose. Culms 30-80 cm, usually erect; nodes and internodes appressed pubescent. Sheaths glabrous or pilose, margins ciliate; ligules to 2 mm, membranous, ciliate; blades to 20 cm long, usually less than 2 mm wide, filiform, scabrous adaxially. Panicles 1-5 cm long, 1-3 cm wide, occasionally reduced to a raceme. Spikelets 9-12 mm, with 2-5 florets. Glumes subequal, 3.4-4.5 mm, acuminate; lemmas 4-8 mm, lobes 4.5-8 mm, tapering to the acute apices; awns 8-11 mm, divergent; paleas 2-3 mm, keels ciliate; anthers 1.5-2 mm, yellow. Caryopses 1.5-2.5 mm, ovoid, tan. 2n = unknown.

Triplasis americana is endemic to the southeastern United States. It grows on sandy soils in prairies and woods, being less common in maritime dunes than Triplasis purpurea.