Comparative ontogeny elucidates subtle changes in developmental rate, known as heterochrony, that discretely alter morphology between species. Vasconcelos et al. show how these trends explain evolution of Eugenia (Myrtaceae) megadiversity in contrast to its apparent flower uniformity.
Selected steps of the floral ontogeny were described and compared between 21 species; trait data were contrasted for correlation analysis. Heterochrony was evident from size differences between structures at similar developmental stages. These differences underlie variable levels of investment in protection and subtle modifications to symmetry and breeding system, producing a wide spectrum of floral display and contributing to fluctuations of fitness in the genus.