In Ky. this is locally common on limestone bluffs along the Kentucky River Palisades, and in transitional populations further east. Colls. from ESTI and PULA (KY) mapped here under var. affine are somewhat intermediate plants, or in mixed populations with more hairy plants. See notes under var. rafinesqueanum. Distinction from the dentatum group can be difficult (F, W). Petioles below cymes are distinctly shorter (usually 0-8 mm versus 8-15 mm), but on vegetative branches, there is little or no significant difference. Stipules are present (versus often absent). Leaves tend to be smaller (mostly 3-8 cm versus 3-12 cm), with fewer teeth on average (4-10 versus 4-22). Cymes tend to be smaller (1.5-6 cm wide versus 3-11 cm). Seeds are "slightly 2-sulcate on the faces" (versus with "ventral groove narrow, deep and furrow-like").