Biogeography And Habitat Evolution Of Saxifragaceae, With A Revision Of Generic Limits And A New Tribal System

The family Saxifragaceae, the current composition of which is one of the great surprises of molecular systematics, has been subject to massive improvements in the knowledge of phylogenetic relationships. Nevertheless, developments from phylogenomic efforts have yet to be mobilized to inform biogeography and taxonomy. Here, we use a recent order-level phylogeny for Saxifragaceae and related families covering 72% of species with a set of new analyses to assess habitat evolution and biogeography. Our results suggest a North American origin of the family in cold alpine habitats, followed by rapid recent evolution of diverse habitat tolerances. We also combine these recent phylogenomic results and a synthesis of the literature to improve generic limits and tribal classification of Saxifragaceae. We recognize 40 genera in 10 tribes, with 14 new combinations, and elevate one subtribe as well as describing four new taxa at the tribal level. Finally, we synthesize information about biogeography and morphology for the family.