Mammillaria sphacelata ssp viperina belongs to the family Cactaceae (the Cactus family). It is an evergreen succulent perennial that is native to southern Mexico, Puebla and Oaxaca. This cactus is commonly clustering, forming sprawling clumps up to 60 cm in diameter. The stem is cylindrical, bright green, and it can reach about 20-30 cm in height, no more than about 2 cm in diameter. The tubercles are conical, and the axiles are filled by woolly white hairs. It has 6-10 central spines and 18-24 radial spines. The flowers are carmine to dark purplish red, to 15 mm long, and bloom from spring to early summer.