Twining perennial herb to 4 m, glabrous or nearly so; lvs cordate-ovate, 5-10 cm, glaucous beneath; peduncles 3-6 cm; fls in short, raceme-like or irregular cymes on pedicels 5-10 mm; cor lavender or purplish or whitish, the flaring tube only 2-3 mm, the lobes 7-8 mm; style-tip prolonged 6-8 mm, shortly bifurcate; fr lance-ovoid, 4-7 cm, tuberculate; 2n=22. Native of e. Asia, intr. as a cornfield-weed in Io. June, July.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.