Evolution of floral symmetry in Papaveraceae

Papaveraceae are almost unique in angiosperms for having disymmetric flowers, a rare condition of floral symmetry defined by two perpendicular planes (as in Lamprocapnos spectabilis, pictured). Yet most species of Papaveraceae are in fact actinomorphic (radial symmetry) or zygomorphic (bilateral symmetry). In a new study combining phylogenetics and comparative analyses, we demonstrate that disymmetry has been an intermediate step from actinomorphy to zygomorphy in this plant family.

The paper just came out:
Sauquet H, Carrive L, Poullain N, Sannier J, Damerval C, Nadot S. 2015. Zygomorphy evolved from disymmetry in Fumarioideae (Papaveraceae, Ranunculales): new evidence from an expanded molecular phylogenetic framework. Annals of Botany: In press. link