Resumo. This study aimed to evaluate the influence of bioclimatic variables and tree species migration routes on the phytogeographic pattern of different forest physiognomy in southern Brazil. For this proposal, floristic check-lists of tree species of Araucaria Forest (AF), Subtropical Rain Forest (SRF), Seasonal Deciduous Forest (SDF) and Seasonal semi-deciduous Forest (SSF) were extracted from the scientific literature. The vegetation matrix went through a detrended correspondence analysis (DCA) and, subsequently, the environmental matrix was adjusted to the ordination axes. The significant environmental variables (p ≤ 0.001) were plotted as vectors in the ordination diagram. A Multivariate Regression Tree (MRT) was used in order to analyze the floristic relationship among areas in function of bioclimatic variables. The eigenvalues for axis 1 and 2 of the DCA were, respectively, 0.49 and 0.25, which indicated high species turnover along axis 1, strongly associated with mean temperature of the wettest quarter, minimum temperature of the coldest month, altitude and annual average temperature. The results allowed the conclusion that (i) there is greater floristic similarity between Araucaria Forest and Seasonal Forests, and (ii) the tree component of southern Brazil forests shows physiognomic and floristic variation in response to bioclimatic heterogeneity and migration routes.