This is largely restricted to swamps on the southeastern Coastal Plain, extending upstream to bottomlands of the central Mississippi, lower Ohio and lower Wabash rivers (PL). In Ky. there are several old or uncertain records that need verification, including those of Gm as far as TRIM. Without fruit, aquatica can be hard to distinguish from triacanthos, which occasionally occurs along the margins of swamps intermixed with aquatica. G. aquatica differs as follows (Isely 1990; Y, W): legume ovate, 3-8 cm long and 1-3-seeded (versus elongate, 20-40 cm long and multi-seeded); seeds 10-12 x 7-10 mm (versus 9-10 x 6-7 mm); foliage glabrous or slightly puberulent when young (versus puberulent even when aged). thorns usually simple or few-branched (versus often several-branched on trunks). However, hybrids appear to occur in several areas across the range (Y), including Ky. Curiously, phylogenetic analysis of DNA has shown that the generally "aquatica" is paraphyletic, indicating several separate divergences from the evolutionary line that led to triacanthos (Schnabel et al. 2003). Does this analysis suggest that early evolution of Gleditsia in North America occurred in swampy lowlands (rather than drier uplands), perhaps in association with wallowing of megafauna? See also notes under triacanthos.