Herbaceous, unarmed, climbing to 2.5 m, often freely branched; lvs numerous (more than 25), most of them with tendrils, at base cordate to rounded, at apex acuminate to cuspidate or broadly rounded, always with convex lateral margins; peduncles numerous, individually axillary to the foliage-lvs, flattened, with numerous (mostly more than 25) fls; tep 3.5-5 mm; anthers 1-2 mm; fr 8-10 mm; seeds 3-6; 2n=26. Moist soil of open woods, roadsides, and thickets. May, June. Three vars..
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.