Dioscorea alata - Perennial tuberous root vegetable. NB- Tubers must be eaten cooked, toxic if eaten raw. Purple yam as the name suggests produces purple edible underground tubers. Use tubers as you would potatoes, can also be made into a flour. The tubers are also used in traditional medicines. Evergreen in warmer areas, for me here with occasional frosts it dies back but the tuber survives under ground and reshoots in the spring. A really beautiful looking plant, the new growth is a lovely striking red purple colour, maturing into shiny green heart shaped leaves. A climbing plant, requires something to grow up