Habitally like the next 2 spp.; invol 11-18 mm high, generally higher than broad, even as pressed; appendages of the invol bracts conspicuously blackish at least in part, 1-3 mm, the middle and outer ones deeply and rather regularly pectinate; marginal fls enlarged and ray-like; pappus mostly wanting; 2n=22, 24. Fields, roadsides, and waste places, now widely established in se. Can. and ne. U.S., s. to Va. and W.Va. July-Oct. (C. nigrescens; C. vochinensis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
