Reconstructions of the phylogenetic history of Begonia show African species to be basal, with Asian and American species nested within an African grade and Asian species supported as monophyletic. The route of migration for the genus through Asia is not yet clear, but one scenario for the origin of the highly diverse SE Asian Begonia flora is an ancestral lineage migrating across the Himalayan region. This appears to be the only suitable route, given the low altitude of the bulk of the Indian subcontinent.
