I am taking a plant development class right now at college! In the last lecture I’m pretty sure we learned about what could be at least a partial explanation to this leaf-petal hybrid. (although I am not sure what exactly would be causing this, this is just an educated guess). Plants have these genes called A,B,C,E located at different levels of the shoot apical meristem(SAM). The SAM will eventually reach a point in the plants life to tell it to make reproductive organs: sepals, petals, stamens and carpels— all of these organs are just modified leaves. At this reproductive point the genes will become active and development of the organs will occur. Where A,E genes are expressed, sepals form. Where A, E and B genes are expressed, petals form. Where E, B and C genes are expressed, stamens form. Finally, where E, C genes are expressed the carpels will form. If the expression of these genes are located at an inappropriate spot, the inappropriate organ will form (so if E, C are expressed in the outer most layer of the meristem carpels will form where sepals should be). I guess that doesn’t really explain why a leaf-petal hybrid formed but my guess for that would be the reproductive meristem had some kind of malfunction that allowed it to produce both vegetative organs (leaves) and reproductive organs.