This Pokeweed [Phytolacca americana] was photographed on 30 September 2012 at Fletcher Park, with the fruit in a withered state. Pages 318-319, of Wildflowers of the Carolinas, lists it as being in the Pokeweed (Phytolaccaceae) family. It produces a purplish dye and has been used to make inks, which normally turn brown over time.
USDA Plants Listing: Phytolacca americana
In Harvesting Color, it’s recommended to use a vinegar mordant to fix the dye, 1/2 cup for every gallon of water.