Herbs, annual, cespitose. Culms to 30 cm, bases soft. Leaves spreading to ascending, ¼–1/3 length of scapes; sheath borders tan, backs prominently ribbed, glabrous; blades filiform, 0.5 mm wide, involute, margins ciliate-scabrid, surface glabrous. Inflorescences solitary or more commonly in simple, open, rarely compact, involucrate anthelae; scapes filiform (rarely with several spikelets sessile or subsessile at plant base), prominently ribbed, glabrous; proximalmost involucral bract cuspidate or setaceous bladed, exceeding or exceeded by inflorescence. Spikelets red-brown, ovoid to lanceoloid, 3–5 mm; fertile scales ovate, 1.5–2 mm, apex acute, glabrous or distally puberulent, keel prominent, short-excurrent. Flowers: stamens (1–)2; anthers oblong-elliptic, 0.5–0.7 mm. Achenes yellowish to pale brown, trigonous-obovoid, 1 mm, faces rugose. 2n = 84.