Cochliasanthus is a monotypic genus of flowering plants in the family Fabaceae (legumes), order Fabales. Its sole species, Cochliasanthus caracalla, is a perennial vine native to tropical regions of South America and Central America. The plant produces distinctive, highly fragrant flowers with a curled, snail-like or corkscrew shape — giving rise to common names such as corkscrew vine, snail vine, and snail bean. The flowers are multicolored and are reported to have a fragrance reminiscent of hyacinths. In its native range, it is pollinated by bumblebees and carpenter bees. Formerly classified under the genus Vigna, molecular and morphological evidence now supports its placement in the separate genus Cochliasanthus. It is frequently confused with Sigmoidotropis speciosa, another legume also sold under the "snail vine" name, though the two can be distinguished by flower color and fragrance. Thomas Jefferson famously described it as "the most beautiful bean in the world."
Etymology
The name Cochliasanthus derives from the Greek "kochlias" (snail with a spiral shell), referring to the coiled shape of the flowers. The specific epithet "caracalla" is a corruption of the Portuguese "caracol", also meaning snail.
Distribution
The genus is native to tropical South America and Central America. Pollination by bumblebees and carpenter bees has been documented in its native range in Argentina.
Ecology
In its native range in Argentina, Cochliasanthus caracalla is pollinated by bumblebees and carpenter bees. The fragrant flowers, said to smell like hyacinths, attract these insect pollinators with their distinctive curled morphology.
Cultivation
Cochliasanthus caracalla is hardy in USDA zones 9 and above, thriving in full sun with consistently damp soil. It prefers high heat and humidity. In colder climates, it can be successfully grown in containers and overwintered indoors. The vine is perennial where frost is absent.
Taxonomy Notes
Cochliasanthus is a monotypic genus formerly placed within Vigna. The single species, C. caracalla, was reclassified into its own genus based on morphological and genetic distinctions. It is frequently confused with Sigmoidotropis speciosa, which shares common names but differs in flower color (purple vs. multicolored) and lacks fragrance.
History
Thomas Jefferson, an avid gardener and naturalist, described Cochliasanthus caracalla as "the most beautiful bean in the world," highlighting its historical appeal as an ornamental plant.
