Plants treated here as Coreopsis delphiniifolia are questionably distinct from C. major. In 1976, E. B. Smith suggested that members of the taxon he called C. ×delphiniifolia may be hybrids or progeny of hybrids involving C. verticillata and C. tripteris and, possibly, C. major. A problem with such an interpretation is that although all of the 35 or so records for C. delphiniifolia in the sense of Smith map at or near known localities for C. major, all but 2 are from well south of the known distribution of C. verticillata and only 3 are from near known localities for C. tripteris.