Cochliasanthus

Cochliasanthus caracalla is a leguminous flowering plant in the family Fabaceae that originates in tropical South America and Central America. The species is named caracalla, a corruption of the Portuguese caracol, meaning snail.. Thomas Jefferson called this plant "the most beautiful bean in the world". It is the only member of the genus Cochliasanthus and was formerly considered to belong to the genus Vigna. This perennial vine (when grown in a climate without frost) has fragrant flowers said to be reminiscent of hyacinths - with a distinctive curled shape, giving rise to the common names corkscrew vine, snail vine, snail creeper, snailflower or snail bean ; however, two very different plant species are sold and cultivated under the "snail-" names, the other one being Sigmoidotropis speciosa....read more on Wikipedia.