In Ky. this southeastern species is locally common along the Mississippi Rv., lower Tennessee Rv. and lower Cumberland Rv. It is generally rare elsewhere except for a cluster of records along the central Ky. Rv. or nearby. Some disjunct records may be escapes from cultivation; see also Duncan (1967). The genus Nekemias of Rafinesque has been recently resurrected for this species and its East Asian relatives (FNA 12).