This species is rapidly becoming established in all parts of the state and has in some parts already become an annoying weed. Our first report dates back to 1905. In 1915 I made a note that I saw it only once during the year although I had driven more than 5000 miles. Now it has become more frequent along roadsides and in pasture fields and meadows.
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.