Dioscorea alata

Dioscorea alata – also called ube (/ˈuːbɛ, -beɪ/), ubi, purple yam, 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 (hence the common name), but some range from creamy-white to plain white. It is sometimes confused with taro and the Okinawa sweet potato beniimo (紅芋) (Ipomoea batatas 'Ayamurasaki'), however D. alata is also grown in Okinawa. Its origins are in the Asian and Oceanian tropics. Some varieties attain to great size. A "Mambatap" greater yam grown in Maprik, East Sepik District, Papua New Guinea around 1939 was 3.5 m (11 ft) in length.