Mammillaria heidiae Krainz

Solitary or clustering, body globular, to 5.5 cm wide, without milky sap. Tubercles prominent, conical. Axils with 1-5 white bristles to 1 cm. Central spines 1(-2), 12 mm long, yellowish, tip hooked, brownish. Radial spines 16-24, to 10 mm long, white. Flowers greenish yellow, 3 cm long, 2.5 cm wide. Fruit greenish-brown.

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.