Plants cespitose. Culms angled, 25-75 cm, glabrous. Leaves: basal sheaths red-brown; sheaths of proximal leaves glabrous, fronts lacking spots and veins, entire, apex truncate; blades 3-5 mm wide. Inflorescences: proximal bract subequal to inflorescence, 1-3 mm wide. Spikes erect or the proximal pendent; proximal 3-4 spikes pistillate, usually sessile, 2.5-9 cm × 4-5 mm, base attenuate; terminal 1-2 spikes staminate. Pistillate scales purple-brown to black, shorter than perigynia, apex acute, awnless. Perigynia divergent, green, veinless, somewhat flattened, tightly enclosing and distended by the achenes, ovoid, 2.3-4.7 × 1.1-1.8 mm, dull, apex acute, glabrous; beak green, often twisted, 0.1-0.3 mm, orifice oblique. Achenes not constricted, dull. 2n = 66. Fruiting Jun. Rocky streambeds, banks; 0-1500 m N.B., N.S., Ont., Que.; Ark., Conn., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Vt., Va., W.Va. A very common riverine species of eastern North America, Carex torta has an almost identical habit and habitat to the western C. nudata. Carex torta is, however, not a member of the C. stricta subgroup and has unusual green, glabrous perigynia that taper into a triangular, twisted beak with an obliquely bidentate orifice. Carex torta appears to be somewhat transitional to the Cryptocarpae group, based on the pendent spikes, sheath morphology, and large achenes.
From Flora of Indiana (1940) by Charles C. Deam
Frequent south of the lake area on rocky beds of streams, and sand bars in creeks and on their springy banks; rare in woodland swales.
Plants densely tufted, the stout stems 2-7 dm, arising laterally; lowest lvs reduced to bladeless sheaths; main lvs 3-5 mm wide, inversely W-shaped in x-section; terminal spike staminate, 2-4 cm, pedunculate; pistillate spikes 3-6, usually approximate and much overlapping, linear-cylindric, 3-8 cm, the lower short-peduncled and curved-spreading or drooping, the upper sessile or nearly so; bracts sheathless, the lowest lf-like, usually shorter than the stem, the others much reduced; pistillate scales elliptic to oblong, obtuse, about as long as but narrower than the perigynia, with broad, greenish or stramineous midstrip and blackish or deep brown-purple sides; perigynia ovate, 2.5-4.2 mm, half as wide, 2-ribbed, otherwise nerveless, gradually tapering to a minute, bent or twisted beak; achenes lenticular, filling the lower three-fourths of the perigynium; 2n=66. Streambanks, sandbars, and shallow water; Que. and N.S. to N.C., w. to c. Ont., c. O., Tenn., and Ala.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.