Widespread species spanning strong environmental (e.g., climatic) gradients frequently display morphological and physiological adaptations to local conditions. Some adaptations are common to different species that occupy similar environments. However, the genomic architecture underlying such convergent traits may not be the same between species. Using genomic data from previous studies of three widespread eucalypt species that grow along rainfall gradients in southern Australia, our probabilistic approach provides evidence that adaptation to aridity is a genome-wide phenomenon, likely to involve multiple and diverse genes, gene families and regulatory regions that affect a multitude of complex genetic and biochemical processes.