i would say helianthus divaricatus, woodland sunflower

Can you show a picture of the back of the flower? That might help. Helianthus doesn't usually have smooth leaves.

Okay - took me a while to get the photo and rinse off the seed ticks. Here is the back side of the flower. You can also probably see that both the leaves and stems are covered with very fine hairs. Total plant height is about 3 feet, and the flower is roughly 2 inches wide.

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Looks more like a Silphium(Rosinweed) to me.

Yes, I don't know what species it is, but the back of the flower is very much like Silphium.

Here is a link that might be useful:

Thanks for your help. It does look like Silphium, and is probably S. integrifolium.