This variable species is widespread across eastern states. Its numbers have generally been boosted by plantings for reclamation or wildlife. Despite little or no development of rhizobial nodules on roots, there is more potential to fix nitrogen in this genus than in most other Caesalpinioids (Bryan et al. 1996). Colls. from NELS, WOOD (KY) and elsewhere are referable to var. robusta (Pollard) J.F. MacBr., but that taxon is not generally recognized in recent treatments. Its type is a coll. of C.W. Short from "Mountains of Kentucky" (NY).