Mammillaria megacantha var. rigidior Salm-Dyck, Cact. Hort. Dyck., ed. 1849: 18. 1850 Mammillaria megacantha var. rigidior Salm-Dyck, Cact. Hort. Dyck., ed. 1849: 18. 1850Taxon for this nameMammillaria megacantha var. rigidior Salm-Dyck
