No Latin name will be given for this plant. I got my first one when I planted some parakeet seed in my old garden. I suppose it might not be real sunflower, but it is a sunflower to me. This time of year these plants are the shining stars of the garden.
I had to get out my books to do this post. Botany was not my thing in school in fact I was quite a late bloomer when it comes to plants. Mrs. Wm. Starr Dana's book helped me out.
This is a composite flower. That means it has ray flowers and disk flowers. Many flowers are built this way. The ray flowers in the sunflower's case are the bright yellow petals around the center . The disk flowers are the tiny little tubular flowers in the center. The two work together to get the attention of the birds and the bees. The ray flowers catch the eye. The disc flowers deliver the pollen and the nectar.
Here we have a just opening sunflower. The petals (ray flowers) are not quite unfurled. The disk flowers are in a ring around the outside edge of the center. When open they are also yellow.I used to wonder why the hummingbirds were interested in sunflowers. It's the tiny little tubular flowers that they visit.
As the sunflower ages the open disk flowers spiral in from the outside edge . How could this bee have filled her leg baskets with that much pollen from these tiny little tubular flowers?
Here's a closer look. If you count the tiny little disk flowers in this picture, it will give you some idea how numerous they are.
Here the spiral of disk flowers is nearly complete. It's one seed for each disk flower, so the seeds form a spiral too. The goldfinches, black capped chickadees and other birds will be interested in those, and will plant next year's crop with the seeds they drop.