This is a highly variable southeastern taxon, with apparent transitions to tenuifolia and perhaps even aspera (C.W. Short's coll. from MEAD at MO). It has been combined with tenuifolia in some accounts (e.g. Ch, K); Cooperider & Sabo (1969) found that half the colls. in this complex from Ohio could not be clearly assigned. Further south, hispida seems more distinct and relatively frequent on seasonally dried or disturbed terraces near larger streams, especially in the lower Ohio and Mississippi River valleys. It is uncommon to rare in mid-Atlantic states (W). Following Poindexter & Nelson (2011), both hispida and clingmannii differ from tenuifolia in their generally stouter and less branched stems, with hispid to hispidulous angles (versus glabrous to sparsely pubescent); and in their hispid to hispidulous calyx, with lobes almost straight in fruit (versus glabrous to sparsely pubescent, with lobes commonly recurved). S. hispida differs from clingmanii in its rounded leaf bases (versus truncate) and its stem pubescence mostly retrorse (versus spreading). Much hispida also has distinctly shorter petioles than tenuifolia (ca. 1-1.5 cm versus 1.5-2 cm), and is then similar to other taxa, mostly Appalachian. In such plants, the long non-glandular hairs and elongated (lanceolate) calyx lobes of hispida can also serve to distinguish it.