Echinocactus horizonthalonius var. curvispinus Salm-Dyck, Cact. Hort. Dyck., ed. 1849: 146. 1850
Echinocactus horizonthalonius var. curvispinus, Cact. Hort. Dyck., ed. 1849: 146. 1850
is basionym for Echinocactus horizonthalonius f. curvispinus, Handb. Kakteenkult.: 146. 1907