This weedy nitrogen-fixing tree from subtropical Asia is a widespread invasive species in southeastern states. Some records mapped here may come from planted trees, but it is clearly naturalized in many areas, especially on medium-acid soils. Though widely cultivated and naturalized in more southeastern states before 1840 (Rafinesque 1836, 1:41), the first published record for Ky. was in 1950 (F). B did not record it during her extensive field work during 1920-1950, including many parts of Appalachian regions where the species is now so common. [This species and our herbaceous mimosoids are placed here in subfamily "Mimosoideae"; recent analysis supports recognition of this group as a large monophyletic clade (including Prosopis with 10 stamens per flower and Acacia with 20-100), but nested within Ceasalpnioideae, sensu lato (Koenen et al. 2021).]