Aeschynomene nivea Brandegee is treated as a synonym of Ctenodon niveus (Brandegee) A. Delgado in POWO (https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:5972-2).
See also: Cardoso, D. & al. 2020. A molecular phylogeny of the pantropical papilionoid
legume Aeschynomene supports reinstating the
ecologically and morphologically coherent genus Ctenodon. Neodiversity 13: 1–38. (http://www.neodiversity.org/download_pdf/artigo.pdf.84b6599f23dd710a.6e656f642e3133312e312e706466.pdf).