This is considered to have a largely midwestern native range that has expanded to the east after clearance (F, Cr). It may intergrade with polylepis; both are diploids (2n = 24). In 1914, Gm considered aristosa native to Ky., but reported it only from CRIT "and other points along the Illinois Central Railroad." Some colls. mapped here are referable to var. fritcheyi Fern. (with awns retrorsely barbed) or var. mutica Gray (wiith awns rudimentary), but these taxa have not been recognized in recent treatments.