I’m pretty sure flowers, when they are buds, are protected by leaf-like structures called “sepals.” All of the sepals collectively are called a calyx. They protect the bud and are behind the actual flower petals when it blooms. Hope this helped.
There are so many examples for that in different areas, like TPT1 experiment carried out in our lab recently.Here's one link: http://www.alfa-chemistry.com/tpt1-cas-167218-46-4-item-290583.htm