Uwi or coconut yams (Dioscorea alata L. syn. D. atropurpurea Roxb.) is a kind of food tubers. Many kultivarnya which has a purple bulb so that in the English language known as purple yam. In the Malay language is known as cassava only and is generic, so that the Indonesian name is taken from the name of the Java language to distinguish it from the kinds of other tuber.
Uwi are vines that can reach lengths of 10m. Arrowhead-shaped leaves. Plants have flowers arranged compound, grown from axillary, married one. Male flowers compact 1-3cm; female flowers arranged rarely, longer, 15-20cm; purple crown with 2mm long. He can be propagated vegetatively using root tubers (enlarged root) or air bulb (tuber that came out of the stem segment). Tuber roots can be very large, with a length of more than one meter.