Malacocarpus tetracanthus (Lem.) Rud.Mey. in Monatsschr. Kakteenk. 4: 143. 1894 Malacocarpus tetracanthus (Lem.) Rud.Mey. in Monatsschr. Kakteenk. 4: 143. 1894is new combination for Echinocactus tetracanthus Lem., Cact. Aliq. Nov.: 15. 1838Taxon for this nameMalacocarpus tetracanthus (Lem.) Rud.Mey.