Erect perennial, 4-10 dm, rough-hairy; lvs orbicular in outline, 5-7-parted, the segments of the upper lvs again deeply pinnatifid; fls partly solitary on long pedicels from
the upper axils, but chiefly crowded in terminal clusters; bractlets linear to narrowly lanceolate or oblanceolate, ciliate, glabrous or nearly so on the back; pet white to pale purple, triangular, 2-3.5 cm; mature carpels densely hairy, rounded on the back, not rugose; 2n=42. Native of Europe, escaped from cult., along roadsides and in waste places; Que. and N.S. to B.C., s. to Va. and Mo., more common northward. June-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.