Echinomastus unguispinus (Engelm.) Britton & Rose Echinomastus unguispinus (Engelm.) Britton & Rose, Cactaceae (Britton & Rose) 3: 150. 1922 sec. Guzmán & al. 2003≡Echinocactus unguispinus Engelm., Memoir Tour N. Mexico [Wislizenus]: 111. 1848 syn. sec. Guzmán & al. 2003