Ranunculaceae is a family of flowering plants with ca.59 genera and 2500 species and shows tremendous diversity in both vegetative and reproductive organs.The family,therefore,can help answer the important evolutionary developmental (evo-devo) questions that cannot be easily addressed by using all other existing model organisms.In this talk,I will present our recent results on: 1) the molecular mechanisms underlying the parallel losses of petals in different lineages of the Ranunculaceae;2) the molecular basis and flexibility of the floral organ identity determination program in Nigella damascena,a species that produces spiral rather than whorled flowers;3) the tempo,mode,and mechanisms of character evolution in the elaboration of complex petals within the genus Nigella,and 4) the identification and functional studies of the genes and modules that regulate the development of the highly specialized,bilabiate petals of Nigella.