This is largely restricted to rocky calcareous sites of the Edwards Plateau (Tex.), the Ozark region (Ark., Mo., Okl.), and the southern Highland Rim (Ala., Ga., Tenn.). It was collected in DAVI by E.J. Palmer (#17829 at GH) on 10 Jun 1920 from "high alluvial banks of the Ohio River just below Owensboro... However, it may have been a more recent introduction there, as it is usually found only in rocky ground and along bluffs" (Palmer 1927). Baskin & Baskin (1989) reviewed the context of this coll. and suggested that it was from a cultivated plant, but M considered their argument insufficient to reject the species from Ky.'s flora.