Plants without conspicuous rhizomes. Culms 10-75 cm, 1.3-1.8 mm wide basally, 0.5-0.8 mm wide distally. Leaves: sheaths tight, green, fronts hyaline; ligules less than 2 mm, wider than long; widest leaf blades 1.4-3 mm wide. Inflorescences with 3-9 spikes, 1-4 cm × 5-9 mm; proximal internodes 1-3 times as long as proximal spikes; proximal bracts to 6 cm; spikes with 3-10 spreading perigynia. Pistillate scales hyaline with green midvein, ovate, 2-3 × 1.4-1.6 mm, 3/4 length to equaling perigynia, apex acute to acuminate. Anthers 1.5-2.3 mm. Perigynia green to pale yellow, faces weakly veined, 2.5-3.2 × 1.2-1.8 mm, base of body spongy, thickened and longitudinally striate adaxially, spongy region 0.8-1.5 mm, margins entire, serrulate distally; beak 0.7-1 mm, apical teeth 0.1-0.3 mm. Stigmas straight or slightly twisted, 0.05 mm wide. Achenes ovate-circular, 1.3-1.6 × 1.3-1.5 mm. 2n = 40.
Densely cespitose; stems 2-4 dm, rather stiff; lvs elongate, flat, 1-3 mm wide; spikes 4-8, ovoid or subglobose, 5-8 mm, androgynous, the lower separate and subtended by setaceous bracts 1-5 cm, the upper approximate, with much shorter or no bracts; pistillate scales ovate, acute to short-acuminate or cuspidate, nearly as long as the perigynia and usually deciduous before maturity; perigynia green to brownish-green, spongy-thickened at base, 2.5-3 mm, the beak smooth-margined, sharply but shortly bidentate. Dry woods, often somewhat weedy. Var. retroflexa, of Vt. to Ont., O., and Mo., s. to Fla. and Tex., has the spongy perigynium-base distinctly nerved, tumid on the ventral face, the perigynium somewhat biconvex, two-fifths to half as wide as long, acuminately narrowed into the beak. Var. texensis (Torr.) Fernald, of O. and nw. Ind. to se. Mo., s. to S.C., Miss., and Tex., has the spongy perigynium-base nerveless or nearly so, scarcely tumid on the ventral face, the perigynium planoconvex, a third as wide as long, the beak with sides straight or nearly so.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.