Abstract
Summary
Symmetry is a major component of floral diversity. Most flowers are radially or bilaterally symmetric, with bilateral symmetry (monosymmetry) having evolved repeatedly from radial ancestors. Since the identification of the dorsal identity gene
CYCLOIDEA
(
CYC
) in snapdragon, floral monosymmetry has become a classic example of convergent evolution through repeated recruitment of the same developmental program: across nearly all taxa examined, monosymmetry is associated with asymmetric expression of
CYC
along the dorsal‐ventral axis. Despite extensive comparative evidence, the mechanisms by which
CYC
contributes to the development and diversification of floral symmetry remain fragmentary. Here, I examine three key questions concerning
CYC
function and regulation, summarize current mechanistic insights, and highlight directions for future research.