Intense studies of DNA of the genus are being conducted, with preliminary results published for over a hundred taxa, and this promising approach might soon end the arguments.
jarmilae (Halda) Halda
Cactus disciformis Kuntze
Echinocactus disciformis (DC.) K.Schum.
Echinocactus turbiniformis Pfeiff.
Mammillaria disciformis DC.
Pediocactus jarmilae ?