Tribe Arabideae are the most species-rich monophyletic lineage in Brassicaceae, with more than 500 species distributed in the majority of mountain and alpine regions worldwide. Karl and Koch provide a comprehensive phylogenetic analysis for the species assemblage and test for association of trait and characters. They demonstrate the paraphyly of the genus Arabis and consider that the centre of origin of tribe Arabideae is most likely the Irano-Turanian region. Mid-Miocene early diversification started with increased speciation rates due to the emergence of various annual lineages. Subsequent radiations were mostly driven by diversification within perennial species during the Pliocene, but increased speciation rates also occurred during that epoch.