PLANTS CULTIVATED FOR THEIR SUBTERRANEAN PARTS. 55 



names Batatas, camotes, aviotes, ajes} which were foreign 

 to the languages of the old world. The date of his 

 book is 1601. Humboldt'^ says that, according to 

 Gomara, Christopher Columbus, when he appeared for 

 the first time before Queen Isabella, offered her various 

 productions from the new world, sweet potatoes among 

 others. Thus, he adds, the cultivation of this plant was 

 already common in Spain from the beginning of the six- 

 teenth century. Oviedo,^ writing in 1526, had seen the 

 sweet potato freely cultivated by the natives of St. 

 Domingo, and had introduced it himself at Avila, in Spain. 

 Rumphius * says positively that, according to the general 

 opinion, sweet potatoes were brought by the Spanish 

 Americans to Manilla and the Moluccas, whence the 

 Portuguese diffused it throughout the Malay Archipelago. 

 He quotes the popular names, v,diich are not Malay, and 

 which indicate an introduction by the Castillians. 

 Lastly, it is certain that the sweet potato was unknown 

 to the Greeks, Romans, and Arabs ; that it was not 

 cultivated in Egypt even eighty years ago,^ a fact which 

 it would be hard to explain if we supposed its origin to 

 be in the old world. 



On the other hand, there are arguments in favour of an 

 Asiatic origin. The Chinese Encyclopaedia of Agricul- 

 ture speaks of the sweet potato, and mentions different 

 varieties;^ but Bretschneider '^ has proved that the 

 species is described for the first time in a book of the 

 second or third century of our era. According to 

 Thunberg,^ the sweet potato was brought to Japan by 

 the Portuguese. Lastly, the plant cultivated at Tahiti, 

 in the neighbouring islands, and in New Zealand, under 

 the names umara, gumarra, and gumalla., described by 

 Foi-ster^ under the name of Convolvulus chrysorhizus, is, 



Ajes was a name for the yam (Humboldt, Nouvelle Espagne), 



* Ilumboldt, ihid. 



» Ovieclo, Eatausio's translation, vol. iii. pt. 3. 



* Rumphius, Amhoin., v. p. 368. 

 5 Forskal, p. 54 ; Delile, III. 



• D'Hervey Saint-Denys, Rech. sur I'Agric. des Chin., 1850, p. 109. 

 ' Study and Value of Chinese Botanical Works, p. 13. 



• Thunberg, Flora Japon., p. 84. • Forster, PlantcB EscuL, p. 66i 



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