Cynanchum is a genus of about 300 species including some swallowworts, belonging to the family Apocynaceae. The taxon name comes from Greek kynos (meaning "dog") and anchein ("to choke"), referring to the toxicity^[1] of these plants. Hence the common name for several species is dog-strangling vine. Most species are non-succulent climbers or twiners.

Morphology

These plants are perennial herbs or subshrubs, often growing from rhizomes. The leaves are usually oppositely arranged and sometimes are borne on petioles. The inflorescences and flowers come in a variety of shapes.

Like other species of the milkweed family, these plants bear follicles, which are podlike dry fruits.

Distribution

These species are found worldwide in the tropics and subtropics. Several species also grow in temperate regions.

Importance

The root of Cynanchum atratum is used in Chinese traditional medicine and called Bai wei. Several other species had traditional Chinese medicinal uses.

Cynanchum louiseae, the black swallowwort, is a troublesome noxious weed in parts of the northern United States.^[2]

Classification

Cynanchum as defined in the late 20th century (to include about 400 species) is polyphyletic and is being broken up. Species are being moved to genera including Orthosia, Pentarrhinum and Vincetoxicum, with a group of mostly Old World species staying in Cynanchum.^[3][4]

Species

Species include:

References

External sources

• Cynanchum at Flora of China