Mammillaria chionocephala J.A.Purpus

Typically solitary, body globular to 12 cm wide. Tubercles prominent, 4-sided. Axils white woolly. 2-6 white central spines, tips dark and hooked 6 mm long, 22-24 whitish radial spines 8 mm long. Flowers white to pale pink, 1 cm wide. Fruit reddish purple. [M. ritteriana Boed.]

NE Mexico

Source: Thompson, A, ; Forbes, S.; Spencer, R. (1997). Cactaceae. In: Spencer, R.. Horticultural Flora of South-eastern Australia. Volume 2. Flowering plants. Dicotyledons. Part 1. The identification of garden and cultivated plants. University of New South Wales Press.

kingdom Plantae
phylum   Tracheophyta
class    Magnoliopsida
superorder     Caryophyllanae
order      Caryophyllales
family       Cactaceae
genus        Mammillaria Haw.