Stems 0.5-2 dm, smooth, scattered on long, slender, brownish, sympodial rhizomes; lvs basally disposed, 0.3-1.5 mm wide, often involute or canaliculate; spikes sessile, normally androgynous, inconspicuously bracteate, 4-9 mm, closely aggregated into an ovoid or oblong- cylindric head 8-17 mm; perigynia fusiform-elliptic to broadly elliptic-ovate, 2.6-3.3(-3.5) mm, planoconvex, sharp-edged and ±serrulate distally, ±evidently several-nerved dorsally and sometimes also ventrally, or virtually nerveless, with an evident beak 0.5-1 mm; achene lenticular. Open, often grassy places; irregularly circumboreal, in Amer. from Minn., Io., and Kans. w. across the plains and irregularly in the cordillera n. to Alas.; intr. along railways in Mo. and Ill. (C. eleocharis, the Amer. pls)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.