Astragalus nigrescens var. arctobia (Bunge) Tidestrøm
Astragalus nigrescens var. arctobia (Bunge) Tidestrøm is a synonym sensu FNA Ed. Comm., 2023b of:
Oxytropis nigrescens var. uniflora (Hooker) Barneby, an accepted variety name sensu FNA Ed. Comm., 2023b.