Plants cespitose, short-rhizomatous. Culms 30-80 cm. Leaves 3-5.7 mm wide, glabrous. Spikes 1-2(-3), erect; lateral spikes, if present, usually pistillate; terminal spike gynecandrous; staminate portion 5-18 × 1-3.5 mm; pistillate portion ovate or oblong, 11-35 × 12-20 mm. Pistillate scales 3-4.5 × 0.5-1.1 mm, apex sharply acute or with short, scabrous awn, hidden by perigynia. Staminate scales 3.5-7.1 × 1-2 mm, apex acute, sharp or blunt. Perigynia widely radiating, the proximal reflexed, 5.8-9.7 × 1.9-3.3 mm, smooth; beak 2.1-3.8 mm, usually smooth. Achenes sides often flat, 2.3-3 × 1.1-1.4 mm, 1.9-2.5 times as long as wide; style persistent, sinuous. 2n = 56. Fruiting summer. Wet woods, forest edges, meadows; 0-1000 m; Ont.; Ala., Ark., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Mich., Miss., Mo., Nebr., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Va., W.Va. Carex squarrosa and C. typhina are sympatric over much of the northern part of their ranges and occur in similar habitats. Some evidence suggests, however, that C. squarrosa occurs in slightly drier habitats than C. typhina.
From Flora of Indiana (1940) by Charles C. Deam
Common, especially southward, in low or swampy woods and roadside ditches; frequent on wet borders of ponds and creeks.
Stems 3-9 dm, rather stout, densely tufted, aphyllopodic; main lvs elongate, not clustered at base, 3-6 mm wide; ligule much longer than wide; spikes 1(-3), the lower third staminate, the pistillate part elliptic, 1-3 נ1-5.2 cm, rounded at both ends, very dense; lateral spikes, if present, pistillate, smaller, on erect short peduncles; bract of the terminal spike short and narrow, of the lateral ones foliaceous and elongate but not sheathing; staminate scales acute or acuminate; pistillate scales largely concealed, acuminate or short-awned; perigynia very numerous and crowded, squarrose-spreading, obconic or obconic-obovoid, inflated, the body 3.5-6 mm, its summit with 2 strong ribs and a few obscure nerves, the beak 2-3.5 mm, with teeth 0.2 mm; achene loosely enveloped, rather slenderly ellipsoid-trigonous, 2.2-3 mm, ca two-fifths as wide, the persistent style very strongly sinuous or abruptly bent below. Swampy woods and thickets; Conn. to N.C., w. to w. Que., se. Mich., Nebr., and Ark.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.