XVI International Botanical Congess

The shiitake genus Lentinula has a broad distribution that encompasses much of Asia and Australasia, as well as parts of the Americas. The Old World and New World populations form strongly supported monophyletic groups, which is consistent with a hypothesis of vicariance. Recently discovered fossil basidiomycetes allow calibration of molecular clocks that can be used to address vicariance hypotheses. Two phylogenetic species of Lentinula are resolved in the New World, and five phylogenetic species are resolved in the Old World. Individual species of Lentinula often have complex geographic distributions, which imply that some combination of vicariance, long distance dispersal, and local extinction could have been involved in generating present distributions of shiitake mushrooms in the New and Old World.