Biodiversity of Pinus (Pinaceae) in Mexico: speciation and palaeo-endemism

Mexico, with 43 species of Pinus recognized in the most recent revision for Flora Neotropica, is the richest centre of diversity for the genus. Other centres are California and south-east U.S.A. In comparison, Eurasian pine regions are less diverse. This biogeography, combined with the virtual absence of fossil evidence in Mexico, has led to the consensus that Pinus is a relative newcomer to the region and that ‘recent’ speciation accounts for its diversity. Phylogenetic analysis indicates that several of the oldest and most primitive members of the genus may have originated in this part of the continent and coexist with the species resulting from more recent radiation.