Cynanchum

Cynanchum 

a genus of woody lianas of the family Asclepiadaceae. The leaves are opposite. The flowers are pentamerous and in axillary or apical umbellate inflorescences. The corolla is rotate. Growths of anther filaments form a double crown that encloses the corolla opening. The fruit is composed of one or, less commonly, two follicles; the seeds are tufted.

There are approximately five species (according to other data, 150), distributed in temperate, tropical, and subtropical belts. Four species occur in the USSR. The most well-known species is C. acutum, which is found in the southern European USSR, in the Caucasus, in the Altai, and in Middle Asia (Lake Zaisan). The plant grows on seacoasts, along lakes and rivers, and on slopes. Rubber is contained in the leaves and stems, but it has no practical significance. Some species are poisonous. Plants of the genus Vinatoxicum are frequently included in the genus Cynanchum.