The biogeography and phylogeny of Cardamine L. were inferred based on sequences of the nuclear ribosomal ITS regions and the plastid trnL intron and trnL-F spacer regions. This genus is one of the largest and polyploid-rich genera of the Brassicaceae and has its center of diversity in Eurasia. Species were included from all populated continents, representing all sections except two monotypic ones. The results support a hypothesis of recent and rapid speciation in the genus. The traditional sectional classification was not supported. We found evidence for several extremely long-distance dispersal events. Colonization of the Southern Hemisphere and the Arctic has occurred repeatedly; we identified at least three phylogenetically distinct Arctic lineages, two distinct Oceanian lineages, and four distinct South American lineages. Polyploidization has occurred independently many times during the evolution of Cardamine. Recent divergence combined with widespread polyploidization offer an explanation for the complex taxonomy of the genus.