Fls perfect, 4(5)-merous; sep valvate, persistent, usually tomentose within; pet large, white; stamens 20 or more; ovary inferior, mostly 4-locular with numerous ovules; styles in our spp. elongate, united to or beyond the middle, the stigmas separate and obovoid or united and linear; capsule indurate, obovoid, loculicidal; shrubs with simple, opposite, entire or toothed lvs and conspicuous fls in terminal cymes or short racemes. 50, widespread.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.