This variable species is widespread in wet soil and shallow water across eastern and central North America; 2n = 60-70 (FNA 23). Several colls. from Ky. are referable to var. rubricosus (Fern.) Gilly (= S. eriophorum Michx.), which is a southern form (see also, Ladd & Thomas 2015); a few may be referable to var. pelius Fern., which is a northern form. However, those two taxa have been hard to distinguish in Ky. (Arnold & Beal 1980), and they have not been fully recognized in most recent treatments across southeastern states (even W). Colls. also need to be rechecked for the slightly more distinct species, pedicillatus; see notes under that name.