The sweet potato is an extremely unusual case in that it was transported across the Pacific by Polynesians before the Colombian exchange! In fact, this is some

The sweet potato is an extremely unusual case in that it was transported across the Pacific by Polynesians before the Colombian exchange! In fact, this is some of the most reliable evidence that the preindustrial Polynesians reached South America. http://en.wikipedia.org/wiki/Sweet_potato_cultivation_in_Polynesia http://en.wikipedia.org/wiki/Sweet_potato_cultivation_in_Pol...