Echinocactus polycephalus Engelm. & Bigelow subsp. polycephalus Echinocactus polycephalus Engelm. & Bigelow subsp. polycephalus in Proc. Amer. Acad. Arts 3: 276. 1856 sec. Hunt 2016=Emorycactus polycephalus (Engelm. & Bigelow) Doweld in Succulenta (Netherlands) 75: 270. 1996 syn. sec. Guzmán & al. 2003