This is widely scattered over southeastern states but rather poorly known in Ky., where it appears to be a conservative remnant of native grasslands on dry acid soils in several regions. There has been confusion with sessilifolium, ciliare, and paniculatum. D. obtusum has been considered part of the "ciliare" group, along with marilandicum. It differs as follows (W): terminal leaflets mostly 4-6 cm long (versus 1.5-3 cm), usually longer and narrower than the lateral leaflets (versus similar); stem near middle sparsely to densely uncinate-pubescent (versus glabrous to pilose or with some uncinate-pubescence). These three species share: loments with only 1-2(3) segments; corollas only 3.5-6 mm long; and leaflets not densely pubescent. D. sessilifolium is similar in those chracters, but has subsessile leaves and narrow leaflets. All four species form Series Pauciarticulata of B.G. Schubert (F). Their petioles are relatively short (mostly 0-12 mm) except in marilandicum (10-25 mm).