Look closely and you can spot which of the tiny flowers that make up the center of the Black-eyed Susan is blooming. The immature flowers are flat and smooth, tightly closed in the center. The blooming flowers have stuff sticking out their tops. Anthers make the pollen. Pollen that lands on a stigma goes down a tube and makes a seed when it gets to the flower's egg down at the bottom.
Insects move around pollen for some plants, while other plants count on the wind to move it.
The flowers along the outside edge that have a big petal are called the ray flowers. The flowers in the center are called the disk flowers. I think they actually do have a petal but it is very, very tiny. Did you know most of the kinds of bees in the world do not make honey. Many farmers attract them with special houses because they are hard workers and you need many fewer pollen bees to do a job compared to honey bees.