The Evidence of the Sweet Potato

There is a category of important crop plants which has aroused much speculation and vigorous dispute among Pacific ethnologists because the species included cannot have reached Polynesia merely by the usual marginal diffusion from Melanesia, but speak for direct relations with early America. The principal of these species is the sweet-potato. The sweet-potato, or batata (Ipomoea batatas) belongs to the Convolvulacaea, or Morning glory, family. Genetic studies by Sauer and Tioutine shows that related plant species make it probable that the relationship between the sweet-potato and Ipomoea fastigiata—a wild species of tropical America—is closer than that of the other species in this genus.

The sweet-potato was unknown to Europeans (like the regular potato) until the discovery of America, but before that time according to Dixon was already widely distributed among the aborigines on the Polynesian islands. In post-Columbian times it has become an important food crop in most warm countries.

Hornell wrote that: "Botanists are agreed that America is the area within which the sweet potato was first brought under cultivation. One consequence arising from this conclusion is that the problem of the means whereby it became diffused throughout the island world of Oceania has given rise to great controversy."

A prominent botanist like Merrill, who opposed the view that there was any diffusion of culture plants between the Americas and any part of the outside world prior to the advent of Columbus, still made a specific exception with regard to the aboriginal agriculturists of the Polynesian island world. “They did introduce into Polynesia one important food plant of American origin, the sweet potato, and spread it from Hawaii to New Zealand well before the advent of the Europeans in the Pacific Basin” and he stated that he had “found no references that lead me to believe that the sweet potato reached any part of Papuasia, Malaysia, or tropic Asia, before the arrival of the Europeans.''

He further states that "the sweet potato was spread from South America and not from Central America or the Antilles.” He also pointed out that the sweet potato belongs in a culture complex that operated by vegetal means of reproduction, that is, by cuttings of plants or tubers, and not by seed reproduction, and under ordinary means is multiplied entirely by plant division. Stated differently, the sweet potato could not have migrated on its own by wind or currents from South America to Polynesia except by man carrying it. In fact, botanical analysis and native tradition concur to show that the principal domesticated plants in Polynesia have been carried to these islands by man, partly on his original migration into the ocean, and partly during subsequent centuries of inter-island trade and activity.

Thus an indigenous South American plant not grown elsewhere prior to the Europeans entering the Pacific, found its way from South America, specifically the Andes of Peru, to Polynesia by man’s deliberate introduction. It would seem very likely that Hagoth’s emigrants in the ship that went west and down to Polynesia would have carried such plants. One thing is certain, the sweet potato did not reach Polynesia from Mesoamerica!