Floral evolution across angiosperms has been quite dynamic, where even structures like petals have evolved and been lost multiple times. Contradictory studies have suggested that, in Caryophyllaceae, flowers were either ancestrally apetalous but regained petals later in the phylogeny, or petals were ancestrally present and lost in some early clades. Further convoluting our understanding of the evolution of petals in the family are staminodes, which are present in many of the early apetalous lineages, but we currently do not understand the relationships of staminodes to that of petals. To date, no study has combined dense sampling of taxa with robust phylogenetic comparative methods of well characterized structures based on homology that includes petaloids, staminodes, and differences in their development and positions. Caryophyllaceae, therefore, is an ideal system to study how attractive structures evolve and could provide insights across angiosperms. To provide an evolutionary framework, we reconstructed a phylogeny from two chloroplast regions (maturase-K and the trnL–F intergenic regions) and a nuclear ribosomal marker (intergenic spacer regions 1 and 2). Samples were acquired either from GenBank or from herbarium tissues that were Sanger sequenced, to sample nearly all genera while sampling proportionally at the species level. Phylogenies were reconstructed with maximum likelihood analyses. Flowers were characterized by measuring herbarium specimens of mature flowers and comparing them to scanning electron microscope images of developing flowers to assess structural and developmental homology. We discuss patterns of floral evolution across the family to determine the origin of petals and how they relate to staminodes.