Acmispon rigidus (Benth.) Brouillet, J. Bot. Res. Inst. Texas 2(1): 392. 2008 sec. Brouillet 2008
- ≡Anisolotus rigidus (Benth.) Rydb., Bull. Torrey Bot. Club 33(3): 144. 1906 syn. sec. Brouillet 2008
- ≡Hosackia rigida Benth., Pl. Hartw. [Bentham] 305. 1849 syn. sec. Brouillet 2008
- ≡Lotus rigidus (Benth.) Greene, Pittonia 2: 142. 1890 syn. sec. Brouillet 2008
- =Lotus argensis Coville, Contr. U.S. Natl. Herb. 4: 83. 1893 syn. sec. Brouillet 2008
- =Anisolotus argensis (Coville) A. Heller, Muhlenbergia 9: 67. 1913 syn. sec. Brouillet 2008