Culms trigonous in cross section, (10-)20-90 cm. Leaves: basal sheaths brown, reddish purple tinged, inner bands slightly fibrillose with age; sheaths spreading pubescent; ligules 2-8(-10.5) mm; blades spreading, 2.5-8 mm wide, pubescent, not papillose abaxially. Inflorescences 8-50 cm; spikes erect or ascending; proximal (1-)2-3 spikes pistillate; terminal 1-3 spikes staminate. Pistillate scales ovate, apex acute to acuminate, scabrous-awned, sparsely spreading-pubescent or glabrous. Staminate scales ovate, apex obtuse to acuminate, shortly scabrous-awned except sometimes the proximal, sparsely to densely spreading-white-pubescent. Perigynia 12-20-veined, 4.8-7.8 × 1.7-2.5 mm, ± densely spreading-pubescent; beak 1.5-2.7 mm, spreading-pubescent, teeth spreading, 0.8-1.7 mm. 2n = 112-114. Fruiting Jun-Aug. Dry to wet fields, ditches, roadsides, railroad embankments, disturbed stream banks, lakeshores, and open forests; 0-600 m; introduced; N.S., Ont., P.E.I., Que.; Conn., Maine, Md., Mass., Mich., N.J., N.Y., Pa., Wis.; Eurasia; introduced New Zealand. Carex hirta was first collected in North America in 1877 in Amherst, Massachusetts, and in 1878 in Philadelphia, Pennsylvania. Completely glabrous forms, known from Eurasia, have not yet been found in North America.
Vigorously colonial by creeping rhizomes; aphyllopodic, 3-10 dm; sheaths hairy at the mouth and usually on the back; main lvs 3-6 mm wide, often sparsely hairy; staminate spikes 1-3, 2-3 cm, only the upper one peduncled; pistillate spikes 2-3, widely separated, cylindric, 2-5 cm, densely fld, erect, short-peduncled; bracts lf-like, short-spreading at base, often surpassing the stem; pistillate scales lance-ovate, half to fully as long as the perigynia, usually sparsely villous, acute to acuminate or awned; perigynia narrowly ovoid, 5-8 mm, hairy, conspicuously nerved, acuminately tapering into a beak over half as long as the body, its divergent teeth 1-1.5 mm; achene trigonous. Native of Europe, intr. in waste places and dry fields from P.E.I. to Wis. and D.C.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.