Plants perennial; rhizomes clustered, stout, nodulose, hard. Culms usually in tufts, stout, 40–100 cm, glabrous, somewhat scabrous distally. Leaves: sheaths purplish, not winged, pilose or glabrous; contra-ligules ovate, rarely trigonous; blades linear, ribbed, shorter than culms, 3–9 mm wide, rigid, margins and midrib scabrous, sometimes slightly pubescent. Inflorescences terminal and axillary, fasciculate; fascicles 3, 15–40 × 5–15 mm, each with (1–) 3–10(–12) spikelets (smaller numbers in shade forms); lateral peduncles erect, often becoming filiform and pendulous in deep shade forms; bracts subtending inflorescence leaflike, lanceolate, 3–11 cm, long-acuminate-attenuate, ciliate or glabrous. Spikelets bisexual and staminate (sometimes reduced to few flowers in bisexual spikelets), brown, 3–9 mm; staminate scales ovate-mucronate to lanceolate-acuminate, pistillate scales ovate, midrib excurrent, often awnlike. Achenes sometimes grayish brown, sometimes with dark longitudinal bands, ovoid to subglobose, 2–3 mm, smooth, shining, apex obtuse; hypogynium low, obscurely 3-angled, covered with whitish or brownish, siliceous, papillose-spiculose crust.
"Culms to 1 m, from hard, knotty rhizomes; main blades 4–8 mm wide, often hairy, abruptly attenuate; cymes 1–3, the lower pedunculate; bracts foliaceous, the lowest erect, 5–15 cm; staminate scales lanceolate, acuminate; anthers 2.5–4 mm; pistillate scales ovate, the midrib prolonged into a short awn; achenes white, rarely drab or gray, 2.5–3.5 mm, apiculate, the body as long as or a little longer than thick, blunt or apiculate; hypogynium white, papillose-crustaceous. Moist or dry sandy soil and pine-barrens; Mass. to Wis., s. to Fla., Tex., Puerto Rico, and Mex. (S. flaccida; S. nitida)"