Dioscorea is a large genus of flowering plants in the family Dioscoreaceae, native throughout the tropical and warm temperate regions of the world. The vast majority of the species are tropical, with only a few species extending into temperate climates. It is named after the ancient Greek physician and botanist Pedanios Dioscorides. Mostly they are tuberous herbaceous perennial climbers, growing 2 to 12m in height. The leaves are spirally arranged, mostly broad heart-shaped. The flowers are individually inconspicuous, greenish-yellow, with six petals; they are mostly dioecious, with separate male and female plants, though a few species are monoecious, with male and female flowers on the same plant. The fruit is a capsule in most species, a soft berry in a few species. Several species, known as yams, are important agricultural crops in tropical regions, grown for their large tubers. Many of these are toxic when fresh, but can be detoxified and eaten, and are particularly important in parts of Africa, Asia, and Oceania. Caudiciform species include Dioscorea elephantipes, Dioscorea dregeana, Dioscorea hemicrypta, Dioscorea macrostachya, Dioscorea mexicana, Dioscorea rupicola, Dioscorea sansibarensis and Dioscorea sylvatica. One class of toxins found in many species, including Dioscorea sylvatica, is steroidal saponins, which can be converted through a series of chemical reactions into steroid hormones for use in medicine and as contraceptives. They do very well in pots and rockeries.

Dioscorea mundii is a near threatened South African endemic caudiciform succulent with twining stems to 5m long. It bears greenish flowers during autumn & winter. Found in the Eastern Cape and Western Cape provinces from Nature’s Valley to George, it is often encountered amongst fynbos in coastal forests on mixed dunes and the edges of afromontane forest.