Cor small, campanulately subrotate, with short, broad lobes; corona a fleshy, lobed cup, from a little shorter to a little longer than the gynostegium; anthers terminating in a conspicuous, erect to inflexed membrane; pollinia solitary in each pollen- sac, pendulous, apically attached to the translator; perennial, usually ±strongly viny and twining (seldom erect) herbs with pedunculate extra-axillary cymes solitary at the nodes. 15, temp. Eurasia. (Often included in Cynanchum)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.