Behold the cup plant. It gets it's name from the fact it has cups where the stems touch the leaves. These collect water and probably help prevent insects such as ants from climbing up to the flowers and stealing nectar or certain herbivore insects doing what they do best.
Getting past this defense is a simple hop away but it deters enough to make a difference. Other insects are thrilled to find their small pools of water. I want to say I've read something about frogs using them for tadpoles but I'm probably thinking of another plant from the tropics. Even so they are vernal pools of water, all be it shallow one, that are ideal for certain insects. The mosquito comes to mind but frankly I haven't seen any in the cups which is baffling.
This plant is not for everyone! Yes it gets 10' tall, has lots of tiny sunflower-like flowers, and produces seeds Goldfinches supposidly love. But this plant can also be invasive and it spreads by rhizomes to form a small clump. This is only the second year I've had this plant and it didn't flower that well last year. I'll be sure to post back how true this is. All the images I see of it online depict it as clumps in fields growing randomly but spread out from one another. I also see some butterflies and bees on the flowers too!