Echinocactus simpsonii var. robustior J.M.Coult. in Contr. U.S. Natl. Herb. 3: 377. 1896
Echinocactus simpsonii var. robustior in Contr. U.S. Natl. Herb. 3: 377. 1896
is basionym for Pediocactus robustior in Cact. Succ. J. (Los Angeles) 44(5): 222. 1972
is basionym for Pediocactus simpsonii subsp. robustior, Gen. Pediocactus, Navajoa, Toumeya Revised: 41. 1995
is basionym for Pediocactus simpsonii var. robustior in Cact. Succ. J. (Los Angeles) 34(1): 19. 1962