DUAL SYMMETRY FLOWERS. “Nearly all characterized bilaterally symmetrical lineages contain two or more duplicates of CYC2 genes. Plants with floral heads (compact inflorescences) that contain both radial and bilaterally symmetric flowers, such as those in Asteraceae and Dipsaceae, appear to have the greatest numbers of CYC2 genes with differential expression tied to changes in floral symmetry across the inflorescence axis.”
http://onlinelibrary.wiley.com/doi/10.1111/nph.13198/full