The major radiations that punctuate angiosperm evolution are often associated with innovations in floral architecture. The field of plant developmental evolution seeks to understand the generation of this diversity using comparative genetic approaches that build on work done in model species such as Arabidopsis. This strategy has been particularly successful when applied to the genetic program controlling floral organ identity, but is also making advances in the area of floral symmetry. As useful as the “candidate gene” approach has been, alternatives are required to investigate morphological phenomena that are not represented in model species. Other options include methods based on quantitative trait loci and DNA sequencing, which have the additional benefit of facilitating the development of new model species. The combination of all of these approaches across a wide range of species has the potential to elucidate the genetic underpinnings of both recent and ancient radiations of flowering plants.