This chapter summarizes the principal points of the book and emphasizes the importance of Melampodium as a case study for understanding modes of chromosomal change during plant speciation. A combination of molecular phylogenetic, molecular cytogenetic, and quantitative biogeographic analyses has allowed new insights into evolutionary relationships, spatial affinities, and processes of speciation. Species have diverged chromosomally in parallel into dysploid lines followed by polyploidy to tetraploid and hexaploid levels. Throughout this process, species have adapted to different ecological zones, especially in the ancestral area of western Mexico.