Plants perennial; rhizomes elongate, nodulose, to 5 mm thick. Culms usually in tufts, erect, slender, 30–60(–70) cm, sometimes appearing weak, glabrous or hairy. Leaves: proximal sheaths purple tinged, the distal rosy red-tinged, usually narrowly winged, ribbed, pubescent or glabrous; contra-ligules ovate; blades linear, ribbed, shorter than or equaling culms, 2–6 mm wide, glabrous or ciliate to scabrous. Inflorescences axillary and terminal, of 2–5 small clusters, 5–20 × 5–10 mm, each with 1–4 spikelets; the lateral on reddish filiform peduncles dilated toward apex, hairy or scabrous on angles; bracts subtending inflorescence leaflike, linear-lanceolate, 3–10 cm, glabrous or ciliate. Spikelets bisexual and staminate, staminate part frequently reduced in bisexual spikelets, purple tinged, 3–8 mm; staminate scales lanceolate; pistillate scales ovate, acuminate. Achenes white or grayish or grayish brown with dark longitudinal bands, ovoid, shorter than scales, 3–4 mm, smooth, shining, apex umbonate; hypogynium golden brown, rather broad, base obtuse-trigonous, supporting 8–9 small, round or elongate, granulose-spiculose tubercles.

Fruiting spring–summer. Mixed mesic to xeric woods or glades, wet meadows; 0–500 m; Ala., Ark., D.C., Fla., Ga., Ill., Ind., Ky., La., Miss., Mo., N.C., Ohio, Okla., S.C., Tenn., Tex., Va.; Mexico; Central America (Guatemala, Honduras)

Scleria oligantha sometimes extends from its typical wooded habitat to open areas.