Plants usually loosely cespitose; rhizomes spreading to erect, purplish brown to reddish brown, 0-10 mm, slender. Culms arching to spreading, 5-31 cm, smooth or scabrous distally; bases (remnants of old leaves) weakly or not at all fibrous. Leaf blades pale green, shorter to longer than culms, 0.9-2.6(-3.2) mm wide, herbaceous, glabrous abaxially, scabrous adaxially. Inflorescences with both staminate and pistillate spikes; peduncles of basal spikes slender, elongate, erect; peduncles of distal spikes 0.6-4(-10) mm; proximal nonbasal bracts leaflike, equaling or exceeding inflorescences. Spikes: pistillate spikes 1-4 (basal spikes 0-2); cauline spikes overlapping, separated by less than 7 mm, with 4-15 perigynia; distal staminate spikes 3.1-11.3 × 0.7-2.7 mm. Scales: pistillate scales pale to dark reddish brown, with narrow to broad white margins, ovate, 2-2.8 × 1-1.8 mm, shorter than perigynia, apex obutse, acute, or acuminate (cuspidate on some basal spikes); staminate scales ovate, 2.4-4 × 1-1.9 mm, apex acute to acuminate. Anthers 1.2-2.5 mm. Perigynia yellowish green to grayish green, veinless, globose to obovoid, 2.3-3.1 × 1-1.4 mm, as long as or longer than wide; beak often bent, pale green, occasionally with reddish brown tinge, 0.4-0.8 mm, ciliate-serrulate, apical teeth 0.1-0.2 mm. Stigmas 3. Achenes brown, obovoid, obtusely trigonous in cross section, 1.3-1.6 × 1-1.4 mm.
Loosely cespitose and with rather short, slender rhizomes; stems slender, 1-2 dm, purple-tinged at base, usually surpassed by the lvs; lvs soft and thin, 1-3 mm wide; slender-pedunculate, near-basal pistillate spikes usually abundant; staminate spike terminal, 2-5 mm, often overtopped by one or more of the 2-4 associated pistillate spikes, the lowest one of these subtended by a green bract 5-20 mm; pistillate scales lance-ovate to oblong, as wide as but shorter than the perigynia; perigynia green, stipitate, 2-3 mm, the body obovoid or pyriform, 2-keeled, finely short-hairy, abruptly contracted to the minutely bidentate beak 0.4-0.7 mm; 2n=36. Moist open places, and margins of woods and swamps; Greenl. to Alas., s. in our range to Mass., n. N.Y., n. Mich., and n. Minn.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.