Syn. Pl. Glumac. 2: 235. 1855.
Plants colonial; rhizomes long-creeping. Culms central, coarse, trigonous, 40–110 cm, smooth. Leaves: basal sheaths pale green to brownish or pale red tinged, base with marescent remains of previous year’s leaves; longest ligules 2–10(–12) mm, less than 2 times longer than wide; blades glaucous, flat to V-shaped, (4–)5.5–13 mm wide, glabrous. Inflorescences 15–50 cm; proximal 2–4 spikes pistillate, ascending to arching; distal spikes erect; terminal 3–6 spikes staminate. Pistillate scales lanceolate to ovate, apex obtuse to acute, glabrous, awn 0.9–8.5 mm, scabrous. Perigynia ascending, obscurely 10–15-veined, veins somewhat impressed, narrowly ovoid, (4.5–)5.5–7.7 × 1.6–3 mm, glabrous; beak obscure, 0.9–1.7 mm, bidentulate, teeth straight, 0.4–0.8 mm.
Phenology: Fruiting Apr–Jul.
Habitat: Swamp forests, river bottoms, shores of streams, ponds and lakes, wet meadows, often in clay soils, seasonally moist sites
Elevation: 0–400 m
Ont., Ark., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Md., Mich., Miss., Mo., Nebr., N.C., Ohio, Okla., Pa., S.C., Tex., Va.
Carex hyalinolepis is abundant in the Mississippi lowlands and often dominant in the understory of open, wet floodplain forests and bottomland meadows. It is a rapid invader of ditches and other disturbed areas. Sometimes extensive stands are seen without fertile culms.
Occasionally, Carex hyalinolepis hybridizes with C. pellita (= C. ×subimpressa Clokey, according to A. A. Reznicek and P. M. Catling 1986), and rarely with C. lacustris. Carex ×subimpressa is sufficiently frequent that it has been treated as a species in some floras. It can form large colonies in suitable sites.