Short-lived perennial 3-7 dm; stem sparingly branched above or simple, villous-puberulent at least above; lvs pinnatifid, 2-6 cm, with winged rachis and deeply toothed or pinnatifid segments, villous or almost floccose beneath; heads solitary and long-pedunculate at the ends of the branches; disk 12-18 mm wide; invol thinly villous-tomentose; rays 20-30, pistillate and fertile, yellow, 7-15 mm; receptacle chaffy throughout, its bracts narrow, with firm yellow awn-tip equaling the disk-fls; achenes compressed-quadrangular, ±striate-nerved; 2n=18. Fields and waste places; native of Europe, sparingly naturalized in much of our range. June-Sept. (Cota t.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.