Penthorum sedoides /Saxifrage Family
I was surprised to find this plant in two different places in one day and it was the first time I'd ever seen it! I found it first in a ditch on the Haw Ridge Greenways trail and then later in the creek at the University of Tennessee Arboretum. Ditch Stonecrop is in the Saxifrage Family. The little fly on the flower on the right side of the plant was hovering, thus the wings are blurred.
Where seen: Haw Ridge Greenways, University of Tennessee Arboretum, Great Smoky Mountains NP, Warriors' Path SP