Another PNAS paper looks at how the sweet potato made its way from South America to Oceania prior to the arrival of the Europeans. Another interesting story of contact from the Southeast Asian periphery!
How The Sweet Potato Crossed The Pacific Before Columbus
NPR, 23 January 2013
Historical collections reveal patterns of diffusion of sweet potato in Oceania obscured by modern plant movements and recombination
PNAS 22 January 2013