Dioscorea alata

Dioscorea alata – also called purple yam, ube (/ˈuːbɛ, -beɪ/), or greater yam, among many other names – is a species of yam (a tuber). The tubers are usually a vivid violet-purple to bright lavender in color (hence the common name), but some range in color from cream to plain white. It is sometimes confused with taro and the Okinawa sweet potato beniimo (紅芋) (Ipomoea batatas cv. Ayamurasaki), however D. alata is also grown in Okinawa. With its origins in the Asian tropics, D. alata has been known to humans since ancient times.