This globally rare species is known mostly from the Ozarks Mts. of s. Mo. and s. Ill.; there are also small populations in n. Ark., s. Ind., and w. Ky. (Semple & Gandhi 2012). Similar plants from sc. Tenn, n. Ala. and n. Ga. (Nesom 1990; FNA 20, W) are now referred to S. porteri Small, in subsection Squarrosae (Semple & Estes 2012). Some of the eastern plants of buckleyi appear introgressed with S. speciosa (to the north), S. petiolaris Ait. (to the south) or similar species. Cr included buckleyi within the whole petiolaris complex (2n = 18, 36, 54), which deserves further revision. This complex (Solidago subsection Thyrsiflorae) is similar to the flexicaulis complex (subsection Glomeruliflorae), but usually has the following differences (F, Y, FNA 20): mature achenes glabrous (versus short-hairy); phyllaries, and sometimes leaves, sparsely to densely stipitate-glandular (versus not at all); outermost phyllaries loosely ascending to recurved (versus appressed-ascending or slightly spreading); inflorescence thyrsiform-paniculate (versus more leafy thyrsiform or in axillary clusters); leaves often firmer (versus membranaceous), the upper ones shallowly dentate to entire (versus sharply serrate to entire), often short-petiolate (versus sessile); stems sparsely to densely short-hairy, at least above the middle (versus not at all or only on inflorescence branches); Without flowers, buckleyi can be also confused with ulmifolia, but lower leaves are smaller than mid-stem leaves (versus equal or larger but often deciduous); leaves are mostly glabrous above except along veins (versus sparsely hirsute to scabrous); and stems are usually more hairy (often villous or tomentose), at least above, and never completely glabrous as in much ulmifolia.