Mapping here is provisional. This taxon occurs mostly in the Mississippi drainage, sometimes on more base-rich soils than typical tenuis, but it also extends east to central Atlantic states (Cr, FNA 23, PL, Y, W). There has been much confusion with typical tenuis, and the two taxa are combined as varieties by some authors. Further work is needed in Ky. to separate records as much as possible. In addition to its distinctly depressed, coarsely rugose achenes, verrucosa can often be distinguished by its relatively thick rhizomes with shorter internodes and more fibrous scales; 2n = 20 (versus 24), but perhaps dubious (FNA 23).