This has a northeastern and Appalachian range. In Ky. and Tenn. (Ch) there are only a few small outlying populations west of the Appalachian Cliff Section, especially along major rivers and in the southern Knobs. In Ky. and elsewhere, there are occasional hybrids with related species, including striata, conspersa and walteri (B, Cr, M); 2n = 20 throughout this group. Without its distinctive glabrous lavendar long-spurred flowers or fruits (Ballard et al. 2023), rostrata can be distinguished from its closest relatives (conspersa, walteri, etc.) by its ovate, often acuminate leaves (versus roundish to ovate, blunt), with margins remotely crenate-serrate (versus closely crenulate, crenate or subentire); and by its stipules with oblong- to linear-lanceolate teeth (versus lanceolate to ovate), up to 3 mm long (versus 2 mm), with weakly lacerate margins (versus weakly to strongly lacerate or laciniate).