Hackelia virginiana, better known as beggar lice. Lol. Everyone knows their Velcro like seeds but seldom are aware that it has a nice purple bloom. It's also a major food source for several different critters. Close up of the plant, the flowers are held on long scrapes which the seeds cling to in a chain till something brushes by.
Ahhh… beggars lice or stick tights. Yep, I should have recognized it. They are a pretty flower but when the pets are adorned with the seeds, it is aggravating.
Your "not sure what this is" flower grows prolifically around my pond. If I recall, it was IDd as a water primrose. Does this look correct? Seed Box (Ludwigia alternifolia)
Believe in yourself even when no one else will. ~ Sasquatch
Judging by plant structure I'd have to say seed box. It stands at the edge of a pond.
Usually there are stands of water loving wildflowers such as monks hood, cardinal flowers, and jewel weed but between floods and chemical death sprayed by the grounds crew I haven't seen any this summer.