This southeastern tree has appeared to intergrade somewhat with the two other species of Celtis in Ky., and more study of variation is still needed within each species. Hayes (2019) has recently confirmed with molecular and morphological evidence that laevigata can occasionally hybridize with occidentalis to produce intermediate diploids. The genus in general is typical of soils rich in bases and NPK, tolerating highly eutrophic conditions (e.g. Belt 2015). In both laevigata and occidentalis, reported 2n = 20, 30 and 40 (FNA 3); but A. Whittemore (Y) has confirmed only 2n = 20 for both species. Some outlying northern or eastern records of laevigata in Ky. deserve further verification, and uncertain status indicated by open dots in the map. But laevigata does occur at scattered sites along bottomlands of the lower Ohio Rv. and lower Kentucky Rv., and it is occasionally adventive on nearby uplands, especially along fencerows and edges. Colls. from several counties, especially in northern and central regions of the state have been identified as the "copiously serrate" (F) var. smallii (Beadle) Sarg., which appears transitional to occidentalis; see notes under that name. It is likely that laevigata is spreading north by seed and pollen. Records of laevigata from the northern half of Ky. may only date from after 1950; more historical analysis of colls. is needed. Typical laevigata and var. smallii have only appeared in Ohio since 2000 (Vincent et al. 2011).