sweet potato

Tropical America, where Kew records it as native from Mexico through Central America to Colombia, Venezuela and Ecuador; in Polynesia before Columbus, from the Peru-Ecuador region by its genetics, where Polynesian languages named it kuumala

Carried, in the tripartite account Roullier and her colleagues test, by Polynesian voyagers from the western coast of South America between 1000 and 1100 and into Aotearoa around 1150 to 1250; brought again in the sixteenth century by the Manila-Acapulco galleons from Mexico to the Philippines as camote and by Portuguese traders from the Caribbean and Central America to eastern Indonesia as batata; named nyami by enslaved Africans in the American South

The sweet potato reached Polynesia before Europeans reached either place. Roullier and her colleagues find strong genetic support for a prehistoric transfer from the Peru-Ecuador region, and the Quechua kumara, cumar and cumal sit close to the Polynesian kuumala, which they read as human introduction and the most convincing example of a putative contact between Polynesia and South America. Muñoz-Rodríguez and colleagues argued in 2018 that the plant was in Polynesia before people were and needed no human carrier, and questioned whether the contact happened at all; two years later Ioannidis and colleagues found conclusive evidence in Polynesian genomes of a single contact around AD 1200 with a Native American people closest to the Indigenous inhabitants of present-day Colombia. The contact is now written in Polynesian genomes, whatever carried the plant. In the American South enslaved Africans called it nyami, a Senegalese name, after the tubers of home, and the word, shortened to yam, became a market label only in the 1930s, when LSU's horticulturists used it to set Louisiana's moist orange-fleshed roots apart; the USDA still requires the words sweet potato beside it. This means that the sweet potato's names map its routes: kuumala across the Pacific, camote and batata on the European ships, and yam, from nyami, in the American South.