Perigynium (1.5-)1.7-2.2 mm wide; stems usually scabrous below the infl; ventral face of sheath of upper cauline lf only shallowly concave, its cleft not extending more than 1(-1.5) mm below the junction with the blade; 2n=40. Mainly on the prairies and plains to the w. of our range, but extending e. to Minn., Io., n. Mo., and occasionally Ind., Mich., and s. Ont. (C. heliophila; C. inops ssp. h.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.