Plants cespitose. Culms 20–35 cm, distally scabrous. Leaves blades 2–3 mm wide. Inflorescences: proximal bracts shorter than inflorescences; spikes erect, distinct, short-pendunculate, oblong, 10–15 × 5–8 mm; lateral 2–3 spikes pistillate, of similar length; terminal spike staminate, androgynous, or gynecandrous. Pistillate scales dark brown, lanceolate, mostly shorter than, also equaling or longer (if longer then without long mucro typical of C. buxbaumii) and as broad as perigynia, midvein lighter colored than body, conspicuous apex acuminate or mucronate, mucro less than 0.5 mm. Perigynia ascending, pale green, veined or veinless, elliptic, 2.5–3 × 1.25–1.75 mm, papillose, especially along distal margins; beak to 0.2 mm, bidentate. Achenes nearly filling body of perigynia. 2n = 106.
Phenology: Fruiting Jul–Aug.
Habitat: Subarctic bogs, forests
Elevation: 10–300 m
Man., Nfld. and Labr., N.W.T., Nunavut, Que., Alaska, n Europe, Asia (boreal Russia).