Thimbleweed, a native species, has been added to the USWildflowers database (08/04/2013.) Scientific name is Anemone virginiana, Photo below was taken at Lula Lake in Walker County, GA on Aug 3, 2013.  Go to the Thimbleweed detail page for more photos and information.

Thimbleweed, Tall Anemone – Anemone virginiana