Plants densely cespitose. Culms pale brown to ivory at base, sometimes with a few brown fibrillose remains of previous year´s leaves, but not densely covered with fibrils; flowering stems 25-110(-200) cm, longer than leaves at maturity, 1-1.3 mm thick, glabrous. Leaves: sheaths glabrous, proximal ones ivory grading distally to light green, all bearing blades, pale hyaline on front; blades flat, (3-)5.5-8.5(-15) mm wide, glabrous on both surfaces, finely scabrous on margins. Inflorescences: peduncles of lateral spikes 5-20 mm, scabrous; peduncle of terminal spike less than 20 mm, scabrous; proximal bracts usually shorter than entire inflorescence; sheaths 20-100 mm; blades 2-3 mm wide. Lateral spikes: 3-5, 1 per node, the proximal well separated, erect to somewhat nodding, distal ones crowded near apex; proximal spikes pistillate with 15-40 spreading perigynia attached 1-1.5 mm apart, cylindric to elongate, 15-60 × 3-5 mm; distal spikes staminate or androgynous. Terminal spike staminate or androgynous with a few pistillate flowers at base, 15-40 × 2.5-3 mm. Pistillate scales white-hyaline with broad green midrib, oblong-lanceolate, shorter than mature perigynia, apex acute, cuspidate, or awned, glabrous. Perigynia green maturing to light brown, conspicuously 2-ribbed but otherwise veinless except for short inconpicuous veins at base, substipitate, tightly enveloping achene, obovoid, 4.5-6 × 1.4-1.8 mm, membranous, apex abruptly narrowed to tubular beak, glabrous; beak bidentate, slender, 2-3 mm, teeth 1 mm. Achenes sessile, 2.2-2.6 × 1.2-1.5 mm. 2n = 58 (Czechoslovakia, Germany, Great Britain, Iberian Peninsula, Poland, Sweden) Fruiting summer. Disturbed areas in deciduous forests; introduced; Ont.; N.Y., N.C.; Europe; introduced New Zealand. No hybrids are reported in the flora, although in Europe Carex sylvatica hybridizes with C. strigosa and C. hirta.
Much like no. 147 [Carex arctata Boott]; perigynia 5-6 mm, the body sessile, obovoid, conspicuously 2-ribbed, otherwise nerveless, the beak slender and nearly as long as the body. Native of Europe, naturalized from L.I. to s. Ont.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.