World Trade and Biological Exchanges Before 1492, Revised and Expanded Edition postulates that 127 tropical and subtropical plants and animals were transported across oceans to and from tropical continents by early tropical mariners. This volume summarizes our research, opening up new avenues of research and challenging the current ideas of how species were dispersed across the world oceans. A plant, especially a domesticated one, cannot evolve twice on two opposite continents; they require a native wild DNA source. It takes finite time for the species to spread. Eighty-four tropical plants...