There are several species in the genus Dioscorea that are known as yams. The two most important ones in the Pacific are Dioscorea alata (greater yam, water yam) and Dioscorea esculenta (lesser yam, potato yam). Both of these species originated in southeast Asia and very early were carried by voyagers into the Western Pacific and brought D. alata as far east as Hawaii.
Yams continue to make an important contribution to nutrition and food security in most Pacific islands. In addition, Dioscorea alata is an important prestige food in Papua New Guinea, Fiji, Tonga, Vanuatu, Samoa and the Federated States of Micronesia.