I don’t know much about flowers, so I had to look this one up on an Illinois wildflower database. The Mayapple grows underneath the large leaves almost hiding the flower from view. As a matter of fact on this very walk (at Rock Cut State Park), I had gone right past some of them and didn’t even see them until I was walking back in the opposite direction. Apparently the flower will not grow on a plant with only one leaf. The one in my photo must have had more leaves at one time.