This diploid species (2n = 46) ranges widely across eastern North America and into the Great Plains. Its leaves vary much in size, shape, serration, pubescence, and length of petiolules, but the taxonomic significance remains uncertain (Cr, Nesom 2010b, Campbell 2017). Trees mapped here with largely glabrous leaves and twigs are much more common than hairy ones in Ky., especially in riparian zones and nearby sloughs. Open dots mapped here indicate colls. of the species, but with uncertain assignment to variety. F. pennsylvanica, like other species in section Melioides, appears to be strictly dioecious, but there are few definitive data.