Succulent Cactus Mammillaria discolor v. longispina Rog-535.
A distinctive feature of the genus is the presence of an areola divided into two clearly separated parts, one of which occurs at the top of the tubercle, the other at its base. The upper part has a spine, and the base part is always spineless, but usually carries some bristles or wool. The base part of the areola bears flowers and fruits, and is the branching point. The upper part of the areola does not bear flowers, but under certain conditions it can also function as a branching point.