Short-lived perennial, stout, 1-2 m, glabrous and glaucous; lf-segments mostly 1-4(-5) cm, well under 1 mm wide; rays 10-40, unequal, mostly 2-8 cm at maturity; fr 3.5-4 mm, the ribs acute; 2n=22. Native of the Mediterranean region, now found throughout much of the U.S., especially southward, and elsewhere in warm regions.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.