Dioscorea was named after Dioscorides a 1st Century Greek physician and herbalist. Perennials with tubers usually arising from rhizomes, stems usually twining (? clockwise). Leaves simple to palmately compound, usually alternate and usually cordate at the base, sometimes lobed. Inflorescence axillary with small inconspicuous flowers, unisexual in the subfamily Dioscoreoideae. Perianth in two whorls, 3+3. The inferior ovary has 3 locules, style branched. Fruit in the large genus Dioscorea is a 3-winged capsule, splitting open along the margin of the wings. Yams (Dioscorea spp.) are a staple food in many countries. Many contain saponins which are used medicinally as well as to stupefy fish etc.