Phylogenetics, a concept being widely-used in biology, is the reconstruction of evolutionary history by building trees that represent branching patterns and sequences. These trees represent shared history, and it is our contention that this approach can be employed in the analysis of Galactic history, where the shared environment in which stars form provide the basis for tree-building as a methodological tool.  In this talk I will discuss how evolutionary trees can be built with twin stars and how this gains new insights into the structure and evolution of the Milky Way.