in J. Lamarck et al., Encyl. 3: 388. 1792.
Plants loosely cespitose; rhizomes horizontally spreading, reddish-brown to dark-brown, (10–) 40–100 mm, slender. Culms 10–45 cm, smooth to weakly scabrous distally; bases (remnants of old leaves) slightly fibrous. Leaf-blades green, 0.5–3.6 mm wide, herbaceous, papillose to scabrous abaxially, papillose to scabrous adaxially, blades of distal cauline leaves well developed. Inflorescences usually with both staminate and pistillate spikes; peduncles of staminate spikes 0.1–7.5 mm; proximal cauline bracts leaflike, usually shorter than inflorescences. Spikes: proximal pistillate spikes 1–3 (–4) (basal spikes 0, rarely 1); cauline spikes overlapping or separated, with (3–) 4–13 perigynia; staminate spikes 8–24 × 1.3–4 mm. Scales: pistillate scales dark reddish-brown, with narrow white margins, ovate, 2–4 × 1.3–2.8 mm, equaling perigynium body, apex obtuse or acute to acuminate; staminate scales elliptic to ovate, 2.9–5.3 × 1.1–1.9 mm, apex obtuse or acute to acuminate. Anthers 1.8–4 mm. Perigynia pale green, veinless, obovoid, 2.2–3.4 × 1.1–1.5 (–1.7) mm; beak straight, pale green, 0.5–0.9 mm, weakly ciliate-serrulate, apical teeth 0.1–0.4 mm. Stigmas 3. Achenes dark-brown, obovoid, obtusely trigonous in cross-section, 1.3–2.3 × 0.9–1.4 (–1.6) mm. 2n = 36.
Phenology: Fruiting early May–late Jul.
Habitat: Well-drained, acidic but cation-rich, sandy, rocky, and loamy soils under hardwood forest canopies, forest edges, savannas, “balds” and in rocky or sandy openings
Elevation: 150–1500 m
Man., Ont., Que., Ark., Conn., Del., Ga., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.Dak., Tenn., Vt., Va., W.Va., Wis.