Echinocactus fossulatus var. quadrispinus Regel, Index Seminum St. Petersburg (Petropolitanus) 1857: 48. 1858 Echinocactus fossulatus var. quadrispinus Regel, Index Seminum St. Petersburg (Petropolitanus) 1857: 48. 1858Taxon for this nameEchinocactus fossulatus var. quadrispinus Regel