Sparingly branched annual or winter-annual 1-6 dm; basal lvs oblong, 5-10 cm, pinnatilobate; cauline lvs much smaller, lanceolate to linear, entire or denticulate, auriculate; racemes becoming much-elongate; pedicels at maturity divaricate, 1-2 cm; sep 2 mm; pet 1.5-4 mm; fr triangular-obcordate, with straight to slightly concave or slightly convex margins, 4-8 mm; 2n=16, 32. Probably native to s. Europe, now a cosmopolitan and ubiquitous weed. (C. gracilis; C. rubella; etc.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.