This is widespread in damp acid woodland and thickets across eastern North America, but it is uncommon to rare west of the Appalachians and in midwestern regions (K). Several varieties have been described by ilicimaniacs (F), but these have been combined in recent treatments (W). Most plants in Ky. have been referred to the relatively hairy var. padifolia (Willd.) Torr. & Gray ex S. Wats. A few colls. from southeastern counties (MCRE, PULA) would be referable to var. verticillata instead. Some colls. from more southwestern regions tend to have narrower leaves, suggesting transitions to other species. Differences in chromosome nuber have been reported and deeper investigation is needed (A. Whittemore pers. comm.)