Sigmoidotropis speciosa

Native from Mexico through Central America to tropical South America, this twining perennial vine grows in wet tropical habitats. Its leaves have three leaflets, and pale violet flowers have a strongly curved keel that gives them a snail-like shape. Slender stems climb by winding around supporting vegetation. Flattened pods contain numerous seeds and split open with twisting valves when mature. Photographed in Chocó, Colombia.