Cal glabrous or nearly so; cor short-conic in bud, abruptly acuminate, twisted, its lobes at anthesis finely hairy above, 5-8 mm, about twice as long as the cal; fr wing-angled; otherwise much like no. 1 [Matelea gonocarpa (Walter) Shinners], and in similar habitats. Se. Va. to Fla. (Gonolobus s.; Vincetoxicum s.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.