Plants densely cespitose; rhizome internodes 1.2–2.8 mm thick. Culms yellow-brown at base, 10–50 cm. Leaves: sheaths glabrous; blades glaucous, widest blades (5.1–)5.7–10.8 mm wide, smooth abaxially or sparsely antrorsely scaberulous on main veins. Inflorescences 0.56–1 of culm height; peduncles of lateral smooth; peduncles of terminal spikes (0.5–)1.6–15(–31) mm, barely to much exceeding lateral spikes; proximal bract sheath loose, abaxially glabrous, sheath front apex truncate; ligules 5.2–10 mm; distal bract slightly shorter than to much exceeding terminal spike. Spikes 3–6, distal 2–4 overlapping; lateral spikes pistillate, longest ones with (14–)19–45(–65) perigynia, 9–32(–41) × 4.1–6.5(–7.3) mm, ratio of spike length (in mm) to flower number = (0.56–)0.67–1.1(–1.3); terminal spikes 7–35 × (1.3–)1.5–3(–3.6) mm. Pistillate scales (1.6–)2–3.2(–3.7) × 1.5–2.2(–2.5) mm, margins whitish, entire, apex awnless or with awn to 1(–1.5) mm. Staminate scales 4.3–5.2 × 1–1.8 mm. Anthers 1.8–3.6 mm. Perigynia spirally imbricate, 43–54-veined, unwrinkled, oblong-ovoid, obtusely triangular in cross section, 3.2–4(–4.1) × 1.5–2.5 mm, (1.5–)1.8–2.3(–2.5) times as long as wide, dull, base very gradually tapered, apex gradually tapered; beak absent or straight, 0–0.3 mm. Achenes obovoid, 2.4–3 × 1.3–1.6(–1.7) mm, 0.5–0.63 times as long as perigynia, loosely enveloped by perigynia; stipe straight 0.05–0.3(–0.4) mm; beak bent (0–)30–90°, 0.2–0.4 mm.
Phenology: Fruiting spring–early summer.
Habitat: Mesic to wet-mesic deciduous forests or seasonally moist prairies, usually in clays or loams
Elevation: 10–1900 m
Ont., Ala., Ark., Conn., Del., D.C., Ill., Ind., Ky., La., Md., Mass., Miss., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., Tenn., Tex., Vt., Va., W.Va.
Carex glaucodea is frequent. In the southern portions of its range, it occasionally grows with and hybridizes with C. flaccosperma (see discussion under 298. C. flaccosperma).