Kongl. Vetensk. Acad. Nya Handl. 24: 153. 1803.
Plants densely to loosely cespitose; rhizomes short, no more than 10 cm. Culms sharply trigonous in cross section, (15–)25–95(–110) cm, scabrous-angled distally. Leaves: basal sheaths reddish purple; ligules as wide to slightly longer than wide; blades dark green, flat to W-shaped, widest leaves (4–)4.5–11.5(–13) mm wide, glabrous. Inflorescences 2.7–18 cm; proximal bract 9–45 cm, exceeding inflorescence; proximal 1–3(–4) spikes pistillate, erect or the proximal often spreading, (12–)15–22 mm thick, if spikes less than 15 mm thick, then usually less than 2.5 times as long as wide; terminal 1 spike staminate. Pistillate scales narrowly oblong, 3.4–11.2 × 0.5–1.1 mm, as long as or shorter than perigynia, margins often ciliate, apex truncate to retuse, erose, prolonged to scabrous awn. Staminate scales with distinct, scabrous awn, sometimes ciliate-margined. Perigynia spreading, strongly 7–12-veined, veins separate nearly to beak apex, broadly ovate, (6–)6.5–10.8 × (1.8–)2–3.5(–4.2), apex contracted; beak 2.5–5.9 mm, 0.7–0.9 length of body, bidentate, smooth, teeth straight, to 0.2–0.8 mm. Stigmas 3. Achenes yellow to brown, trigonous, papillose.
Phenology: Fruiting May–Aug.
Habitat: Wet meadows, marshes, seeps, shores of ponds, lakes, and streams, open swamp forests, ditches, mostly in acidic, often sandy soils
Elevation: 0–1200 m
Nfld. and Labr., N.S., Ont., Que., Ala., Ark., Conn., D.C., Fla., Ga., Ill., Ind., Ky., La., Maine, Md., Mass., Mich., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Tex., Vt., Va., W.Va., Wis., Mexico, West Indies, South America.
Carex lurida is an abundant, variable, and often weedy species. A few specimens appear to be hybrids of C. lurida with C. lupulina.