The genus Erodium is a common feature of Mediterranean climates throughout the world, but the Mediterranean Basin has significantly higher diversity than other areas. Fiz-Palacios et al. find that biogeographic reconstructions point to Asia as the ancestral area of Erodium (approx. 18 MYA), with establishment of Mediterranean climates facilitating the spread of the genus and being crucial in its diversification. In the Mediterranean basin itself, two independent radiations occurred in response to the onset of drought and glacial climate change.