Simple or sparsely branched shrub to 1 m; lvs broadly ovate or oblong to obovate, 4-7 cm long and usually at least half as wide, obtuse or rounded at the tip, rounded to broadly cuneate at the base, irregularly toothed (tending to be doubly serrate) above the middle, glabrous or sparsely villosulous beneath; infl terminal, compound, broadly dome-shaped, 3-10 cm wide, the branches and pedicels thinly hairy to glabrous; hypanthium glabrous or sparsely villous without, white-strigose to glabrate within; fls white to seldom pink, 4-5 mm wide; sep 0.5-0.8 mm; fr glabrous, 2-3 mm; 2n=54. Mt. woods; w. Md., Va., and W.Va. to Ala. June, July. Our plants, as here described, are var. corymbosa (Raf.) Maxim. Other disjunct vars. occur in w. N. Amer. and e. Asia.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.