Perennial; stems erect, 4-8 dm, simple to the infl, pubescent; lvs palmately compound, the lower long-petioled, with 5-7 lfls, the upper smaller, with shorter or no petiole and only 3 lfls; lfls radially divergent, narrowly oblanceolate, deeply toothed; infl flattened, with many fls; sep and bractlets lance-ovate, subequal; pet sulphur-yellow, 1 cm; anthers 1.0-1.5 mm; style terminal; achenes striate with low curved ridges; 2n=42. Native of Europe, found as a frequent weed in dry soil and waste places throughout our range. June-Aug. (P. sulphurea)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.