Plants cespitose. Culms straight, 10-75 cm. Leaves of flowering stems shorter than to slightly exceeding culms, 5-30 cm × 1.6-4.7(-5.8) mm; ligules on distal cauline leaves truncate or rounded. Inflorescences: peduncles of terminal spikes 0.4-5(-9) mm; bracts to 18.5 cm × (0.7-)2-4.5 mm; inner band of sheaths truncate or concave. Spikes: proximal pistillate spikes (1-)2-5, contiguous or approximate, globose to elliptic, 8-22 × 7.5-12.7 mm; terminal staminate spikes sessile or pedunculate, 9-22 × 1.1-3 mm. Scales: pistillate scales reddish brown, 2.3-3.9 × 0.9-1.4 mm; staminate scales reddish brown, ovate, margins narrowly whitish hyaline, apex obtuse. Anthers 1-2.1 mm. Perigynia reflexed, bright yellow at maturity, 4-6.3 × 1-1.9 mm, apex gradually narrowed; beak 1.3-2.7 mm, forming angle of (15-)26-72° with body, scabrous. Achenes 1.3-1.7 × 0.9-1.2 mm. 2n = 60. Fruiting Jun-Aug. Moist to wet habitats, such as open meadows, fens, partially shaded shrub carrs, swamps, on lime-rich soils; 0-2000 m; St. Pierre and Miquelon; Alta., B.C., Man., N.B., Nfld. and Labr., N.S., Nunavut, Ont., P.E.I., Que.; Alaska, Conn., Idaho, Ind., Maine, Mass., Mich., Minn., Mont., N.H., N.J., N.Y., Ohio, Pa., R.I., Vt., Wis.; Europe; Asia (Iran).