The evolutionary advantage of sepals matching petals is there is more to attract pollinators. To know which is which, just look at the three that are attached the lowest -- those are the sepals.

This article was originally published with the title “Cypripedium with Peloriated Sepals” in SA Supplements Vol. 41 No. 1050supp (February 1896), p. 16790 doi:10.1038 ...

Flowers are composed of elements such as sepals, petals, stamens, and pistils, and the symbolic representation of this composition is called a 'floral formula,' and a schematic diagram showing ...