Culms 2-85 cm. Leaves of flowering stems much shorter than culms, to 19 cm × 1-5.4 mm; ligules of distal cauline leaves truncate or rounded. Inflorescences: peduncles of terminal staminate spikes to 25 mm; proximal pistillate spikes 1-4, 5.4-11 mm wide; terminal staminate spikes 5.1-25.3 × 1.3-3.6 mm. Perigynia (2.7-)3.2-4.5 × 1-2 mm; beak forming an angle of (5-)15-40(-58)° with body. Achenes 1.2-1.8 × 0.9-1.4 mm.

Fruiting Jul-Aug. Moist to wet fens and runnels, on lime-rich soils, maritime in North America; 0-500 m; N.B., Nfld. and Labr., N.S., Que.; Europe (from Norway and w Russia to France and Greece).