FROM LEAF TO CARPEL. “Carpels, along with the other principal floral organs, have for long been postulated to be modified from a leaf ground plan. Relatively recent experimental evidence supports this view: floral organs are converted to leaves in plants in which all of the A, B and C function genes, or the redundant E-function genes, are inactivated.”
https://academic.oup.com/jxb/article/57/10/2143/471376/An-evolutionary-perspective-on-the-regulation-of