Plants loosely cespitose. Culms 10-35 cm, distally scabrous. Leaves 2-4 mm wide. Inflorescences: proximal bracts shorter than or exceeding inflorescences; spikes erect, separate, proximal spikes occasionally distant, pedunculate, short-oblong or cylindric, 5-20 × 2-3 mm; lateral 2-5 spikes pistillate, distalmost often reduced to 1-3 perigynia, of varying lengths, proximal 1 or more as long as the terminal spike; terminal spike pistillate, gynecandrous (proportion of pistillate to staminate flowers variable, as few as 2 or 3 perigynia at summit), or wholly staminate. Pistillate scales light to dark brown, distal margins broadly hyaline, ovate, as long and as wide as perigynia, midvein lighter colored than body, conspicuous, often raised, prominent, distally scabrous, apex rounded, acute or mucronate. Perigynia ascending, greenish yellow or brown, veinless, elliptic, 2-2.5 × 1-1.5 mm, apex abruptly beaked, papillose; beak to 0.2 mm, truncate or obscurely bidentate, serrulate. Achenes nearly filling body of perigynia. Fruiting May-Aug. Alkaline meadows, lake margins, roadsides, ditches; 200-2500 m; Alta., B.C., Man., Ont., Sask., Yukon; Alaska, Colo., Idaho, Mont., Nev., Utah, Wyo.
Stems 2-6 dm, loosely tufted on short, scaly creeping rhizomes, phyllopodic, the principal lvs crowded near the base, seldom over 15(-25) cm, flat to channeled and revolute- margined, to ca 4 mm wide; spikes 1-5, the terminal one (1-)1.5-3 cm, often longer than the others, these sessile or stiffly short-pedunculate and ±erect; spikes often all wholly pistillate, or the terminal one frequently staminate, or gynaecandrous, or with intermingled male and female fls; bract subtending the lowest spike scarcely sheathing, usually short and inconspicuous, rarely as long as the infl; pistillate scales stramineous to more often brown with pale, hyaline margins, broadly obtuse and shorter than the perigynia to narrower, acute, and surpassing the perigynia; perigynia ±distinctly obovate, 1.9-3 mm including the short (0.2-0.6 mm) or obsolete beak, often short-hairy distally, 2-ribbed, otherwise nerveless or inconspicuously several- nerved; achene trigonous, rather loosely filling the perigynium. Meadows, swales, and moist low ground on the prairies and high plains; widespread in interior w. U.S. and s. Can., e. to w. Minn. (C. hallii)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.