first one is ironweed.
second one, i'm not sure. I assume the flowers open fully to yellow daisies?

oops. Guess I should have scrolled down a bit huh. I have no idea on the second one, looks like a helianthus or a rudbeckia from the leaves.

Well, I guess I need to take a better picture of the stems on the yellow flowers. The stems are really different. They're not really square, but have tissue that makes them look square. You can see that somewhat by the picture, but I'll get a better picture of the stem lower down on the plant which shows it better. I'll do that next Wednesday when I'm back out at the park. We're labeling all the plants and this one is an unknown. It's right beside the Ironweed, and just as tall. If we can't identify it, we'll have to take it out. But, it's so pretty, I hate to do that. We'll figure it out. I'll post another picture when I can.

try posting to the ID forum- they are quick on the draw!

Get a picture of the back of the yellow flower - that can be fairly distinctive for identification.

It may be Wingstem, Verbesina alternifolia.

Here is a link that might be useful: Verbesina