White flowers with yellow centers growing in a pond. Slightly scalloped, rounded petals, three per flower. There didn't seem to be any foliage attached to it.
And I didn't see the cool spider until I looked at the photos!
Infrequent; patchy clumps in emergent marsh/wet prairie, with Carex pellita and Sorghastrum nutans.
I honestly don't know how to tell this apart from I. virginica. So I'll just pretend I'm a butterfly instead and enjoy it.