The genus commemorates Dioscorides, a first-century CE Greek physician and botanist. There are over 600 species in the genus, spread throughout the tropics and subtropics. They are perennials with tuberous roots or caudices (swollen stem bases), climbing stems and small, yellow-green flowers. Most species are dioecious, having separate male and female plants, although a few are monoecious, with male and female flowers on the same plant.
