Plants perennial; rhizomes elongate, knotted, rather stout. Culms sometimes in tufts, erect, stout to slender or almost filiform, 20–70 cm, glabrous or hairy, especially on angles distally. Leaves: sheaths sometimes purplish, not or scarcely winged, weakly ribbed, densely pubescent or glabrous; contra-ligules subrotund to triangular, short; blades linear, keeled, obtuse, shorter than, equaling, or overtopping culm, 1–7 mm wide, ciliate or glabrous. Inflorescences terminal and axillary, fasciculate, 0.5–2.5 cm; clusters few to many flowered, 5–10 mm wide, each with 2–4(–5) spikelets; axillary clusters sometimes on short erect to slender filiform peduncles; bracts subtending inflorescence leaflike, awl-shaped, to 15+ cm, often appearing to be continuation of culm, conspicuously ciliate or glabrous. Spikelets bisexual and staminate, 4–8 mm; staminate scales lanceolate, membranous; pistillate scales ovate-acuminate, midrib conspicuous. Achenes whitish or often brownish gray, globose, 2–3 mm, base constricted, trigonous, apex usually umbonate, tuberculate or verrucose, rarely smooth, papillate at base; hypogynium golden brown, obtusely 3-angled border, supporting 3 yellowish, globose, spiculose or pulverulent, entire or 2-lobed tubercles.
More
Erect from knotty rhizomes, 3–8 dm; lvs glabrous or hairy, long-attenuate, the larger 2–7 mm wide; cymes 2–3 and approximate or solitary, short-peduncled or sessile, 1–3 cm; pistillate scales ovate, acuminate or short-awned, glabrous or hairy, the prominent midrib projecting as a wing-like keel toward the base; achene globose, white, roughly papillose, (1.5–)2–3 mm thick, minutely apiculate; hypogynium with 3 prominent, transversely ellipsoid tubercles, each often ± 2-lobed. Damp sandy soil and pine-barrens; se. Va. to Fla., Tex., and Cuba, n. in the interior to Mo. (S. elliottii)