Erect, branched at base, 3-10 dm; lvs pale green or bluish, the principal ones twice pinnatifid into oblanceolate segments; fls greenish-yellow, 1 cm wide, the pet inflexed at the tip; 2n=72, 81. Native of Europe, cult. in old-fashioned gardens and sometimes found as an escape along roadsides and in waste places. June-Aug.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.