Perennial, 1-2(-4) m, stellate-hairy when young; lvs broadly ovate to rotund in outline, 1-2 dm, deeply 3-7-lobed, the lobes lanceolate, irregularly serrate, the middle one the longest; fls in a terminal cymose panicle; cal thinly to densely stellate; pet white, 6-10 mm; carpels commonly 10, at maturity acuminate into a slender, erect beak 3 mm; 2n=28. Loose, sandy, often rocky soil in unstable habitats along rivers and on flood-plains; c. Pa. to Md., Va., W.Va., e. Tenn., s. O., and apparently disjunct in nw. O., ne. Ind., and s. Mich., where perhaps adventive. On the Atlantic slope mainly confined to the Potomac and Susquehanna watersheds.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.