Fig. 1. Inferred evolutionary history of petals and MADS-box genes in the eudicots. (A,B) Alternative scenarios for the evolution of petals. (A) The evolution of a bipartite perianth occurred independently in the lineage leading to the Ranunculales as compared with the core eudicots. (B) The evolution of a bipartite perianth occurred prior to the radiation of the eudicots, with losses of this character in multiple lineages. (C,D) Summary of phylogenetic analyses. For comprehensive phylogenetic analyses, see Figs S1, S2 in the supplementary material. (C) The duplication of paleoAP3-like genes resulting in PapsAP3-1 and PapsAP3-2 occurred within the Ranunculales, pre-dating the divergence of the Ranunculaceae and Papaveraceae. (D) The duplication of PI-like genes occurred relatively recently in the Papaveraceae, leading to PapsPI-1 and PapsPI-2 in P. somniferum. Clades in bold represent those containing Paps genes described in this study.