Dioscorea polystachya or Chinese yam (simplified Chinese: 山药; traditional Chinese: 山藥), also called cinnamon-vine, is a species of flowering plant in the yam family. It is sometimes called Chinese potato or by its Korean name ma. It is a perennial climbing vine, native to East Asia. The edible tubers are cultivated largely in Asia and sometimes used in alternative medicine. This species of yam is unique as the tubers can be eaten raw.