This central Appalachian species occurs mostly in rocky woods of the Ridge-and-Valley region from Conn. to Tenn., and it may be expected in the Cumberland Mts. of Ky. and Tenn. There is a coll. of E.L. Braun (# 4944 but not found at US) from banks of Cumberland Rv. in MCRE that has been named allegheniensis, according to M. The closely related southeastern species, P. umbellata Ell., has been reported from along the Obed River in Morgan Co., Tenn. (J. Shaw, pers. comm.). Based on recent literature (as reviewed by W; J. Rohrer, pers. comm.), these two species can be distinguished from americana and mexicana by their smaller fruit (mostly 1-1.5 cm long versus 1.5-3 cm), usually with darker color (usually purple to black versus yellow to red); smaller petals (ca. 4-9 mm long versus 8-15 mm); smaller leaves (mostly 4-8 cm long versus 6-10 cm), more finely and usually single-serrate (versus coarsely double-serrate), with slightly acuminate to obtuse apices (versus distinctly acuminate).