Tufted, erect, 3-8 dm; main lvs 2-4 mm wide, shorter than the stems; spikes 3-7, gynaecandrous, ovoid, 1 cm, sessile and closely crowded; pistillate scales ovate, reddish-brown with broad hyaline margins, largely concealing the perigynia; perigynia 4-5.5 mm, 2-2.5 times as long as wide, plano-convex, narrowly scarious-margined, finely but sharply nerved on both sides, the beak distally terete, reddish-brown at the tip; achene lenticular, 1.5-2 mm; 2n=64, 66, 68. Native of Eurasia, intr. in wet meadows and pastures from Nf. to N.Y. and reputedly to N.C. (C. ovalis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.