Chinese Yam

Dioscorea polystachya, the Chinese yam or cinnamon-vine, is a flowering plant of the yam family that grows throughout East Asia. Its edible tubers, grown largely in East Asia and sometimes used in alternative medicine, are unusual among yams in that they can be eaten raw. In Chinese it is shānyào, literally mountain medicine, or huáishān; in Korean it is ma; in Japan the long cylindrical type is nagaimo. The vines twine anticlockwise and grow 3 to 5 metres long, with leaves up to 11 centimetres across. Warty bulbils, called yam berries, form where the leaves join the stem and are also edible. The tubers can weigh up to 4.5 kilograms and reach a metre underground. It tolerates frost and cooler climates better than other yams. The names Dioscorea opposita and D. oppositifolia have been misapplied to this plant, and the source warns that they name a different, Indian group. It has become invasive in the United States.