HEYERDAHL'S KON-TIKI THEORY — JONKER 537 



great explorers of the period, can be explained only in one of three ways. Either 

 the plant had been introduced by the Spanish from South America in the six- 

 teenth and seventeenth centuries when the earliest European discoveries in the 

 Pacific were being made, or it was of pre-Columbian introduction accomplished 

 either by Polynesians who visited South America and brought the new food plant 

 back with them, or by Peruvian or other American Indian navigators who carried 

 it with them in exploring voyages to the west. 



The first possibility may be rejected for sound historical reasons : 

 the first European travelers reported the occurrence of extensive plan- 

 tations of sweet potatoes in the islands visited. The second possibility 

 is frequently accepted. The third alternative is the one emphasized 

 by Heyerdahl, who argued that the crop is known in Polynesia by 

 its Peruvian name "kumara," and also that, according to old myths, 

 the ancestors of the Polynesians originated from the country where 

 the "kumara" grew. Kiesenfeld (1951), on the other hand, states 

 that according to old Polynesian myths the native country of the 

 Polynesians was situated somewhere in the west. Also, Sir Peter H. 

 Buck, the distinguished former director of the Bernice P. Bishop 

 Museum in Honolulu and a recognized authority in the field of Poly- 

 nesian myths and legends, nowhere in his most readable book "Vikings 

 of the Sunrise" (1937) mentions tales to the effect that the Polynesians 

 came from the east. It was Buck's belief that a Polynesian canoe 

 expedition in pre-Colmnbian times left the Marquesas and, sailing 

 in an easterly direction, reached Peru. After disembarking on the 

 continent, the travelers returned after a short stay in fear of conflicts 

 with the natives, first laying in a supply of sweet potatoes, perhaps 

 among other foods. Harold St. John ( 1953, 1954) , an authority on 

 the vegetation of Polynesia, considered Buck's theory the most likely 

 explanation of the early occurrence of Ipomoea hatatas in the Poly- 

 nesian archipelago. E. D. Merrill, a leading student of the Aus- 

 tralasian tropical flora and a decided opponent of Heyerdahl's theory, 

 at first (1937) considered the sweet potato of American origin and 

 the single American plant among the species mentioned by Heyerdahl. 

 However, in one of his last publications (1954) Merrill stated that 

 it is now admitted that /. hatatas may have originated outside of 

 America, possibly in Africa, by hybridization. In that case it could 

 have been carried across the Atlantic to America a few centuries before 

 Columbus reached the West Indies, and perhaps even earlier by way 

 of Madagascar and the Mascarene Islands to Malaysia, Papuasia, and 

 Polynesia, and even to the west coast of South America. Certainly 

 an investigation of the African species of Ipomoea is needed in order 

 to clarify this hypothesis, and such an investigation may give the prob- 

 lem quite another aspect. According to Merrill, moreover, it is also 



