Perennial from a large, deep-seated, tuber-like root; stems trailing or twining, to 5 m, glabrous or nearly so; lvs glabrous or more often hairy beneath, ovate, entire, acuminate, deeply cordate at base, 5-15 cm, rarely obscurely lobed or angled; peduncles stout, stiff, usually exceeding the subtending petioles, bearing 1-7 fls in a terminal cluster; sep ovate or oblong, 13-20 mm at anthesis, obtuse to broadly rounded, glabrous; cor white with red-purple center, 5-8 cm; ovary bilocular; 2n=30. Dry woods and thickets; Conn. to s. Ont., Mich., and Kans., s. to Fla. and Tex. June-Sept.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.