Dioscorea polystachya or Chinese yam (simplified Chinese: 山药; traditional Chinese: 山藥), also called cinnamon-vine, [2] is a species of flowering plant in the yam family.It is sometimes called Chinese potato or by its Korean name ma. [3] [2] It is also called huaishan in Mandarin and wàaih sāan in Cantonese.It is a perennial climbing vine, native to East Asia.