There are any number of posts in this thread that I could have picked for this brief botany lesson; but this seems like a good one.
Most people would look at this, and think they are seeing a single flower. This one hints at the truth. You can see, within it, a few structures, that themselves appear to be flowers.
In fact, this structure, that superficially resembles a flower, is actually a cluster of very many flowers. It is called a
pseudanthium. Some of the center flowers have bloomed out to a point where their individual nature is fairly obvious; this doesn't necessarily happen with all, or even most pseudanthia, but it is happening here. In many (perhaps most) pseudanthia, the center flowers, if present, remain small and inconspicuous, such that you would have to examine them very closely to see that they are individual flowers. Each of the structures around the edge, which you want to think is a “petal”, is actually also an individual flower.