Mammillaria caput-medusae var. tetracantha Salm-Dyck, Cact. Hort. Dyck., ed. 1849: 15. 1850 Mammillaria caput-medusae var. tetracantha Salm-Dyck, Cact. Hort. Dyck., ed. 1849: 15. 1850Taxon for this nameMammillaria caput-medusae var. tetracantha Salm-Dyck