Stems 0.5-3 dm, in small tufts on long rhizomes; lvs crowded toward the base, slender but flat above, 1-1.5 mm wide; spikes mostly 2 or 3, the terminal one staminate,
6-25 mm, the lateral one(s) pistillate, sessile, approximate, suborbicular or short-oblong, 4-12 mm, with mostly 4-15 ascending or eventually spreading perigynia; bracts short, sheathless; pistillate scales broadly ovate, wider than and nearly as long as the perigynia, reddish-brown, with stramineous 3-nerved center and conspicuously white-hyaline margins; perigynia coriaceous, brown and shining, obovoid, 2-ribbed, nerveless or obscurely few-nerved, 2.5-3.5 mm including the smooth, cylindric beak; achene
trigonous, filling the perigynium; 2n=38. Dry, often rocky slopes; circumboreal, s. irregularly to ne. Minn. and adj. Ont. The infl. is occasionally reduced to a solitary staminate spike with 1 or 2 basal perigynia; such plants look much like C. obtusata, but lack a rachilla in the perigynium.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.