Mammillaria tlalocii is an attractive and rewarding cactus with dense white spines
The slow growth rate  make it one of the most sought-after species.

Family: Cactaceae (Cactus Family)

Scientific name:  Mammillaria tlalocii Reppenhagen 1989
Published in: Gattung Mammillaria 1988: 120 (1989)
First description: by Reppenhagen, Gatt. Mamm. 120 (1987)

Origin:  Mexico, (at the border of the states of Puebla and Oaxaca).

Habitat:  Altitude 800 to 1.000 m.

Conservation status: Listed in CITES appendix 2.

Synonyms:

• Mammillaria crucigera subsp. tlalocii (Reppenhagen) D. R. Hunt 1997
• Mammillaria buchenaui Backeberg 1963
• Mammillaria crucigera var. tlalocii (Reppenhagen) Linzen et al. 1998
• Mammillaria crucigera var. grandinosa Linzen et al. 1998
• Mammillaria crucigera Martius 1832

Description: Globular cactus, solitary or clumping dichotomously; usually this species don't produces lateral shoots. But in cultivation are frequently seen plant that branch profusely from the base.
Stem: Globose, later columnar, curving pipe-shaped, to 20 cm long, 5 to 7 cm wide.
Axil: White-wooled.
Radial spine: 16 to 22, glassy white, 1 to 2 mm long, the longer sideways pointing.
Central spine: On the areoles at the apex of the plant, with age, may appear a single longer brown-black central spine 6-10 mm long.
Flower: Carmine-pink, 12 to 14 mm long, 8 to 10 mm wide.
Flowering time: Blooms in late winter, early spring.
Fruit: Carmine-pink small.
Seed: Small, brown.

Cultivation: It is a  slow growing  species .  Use pot with good drainage and a very porous mineral-based potting mix,  keep dry in winter. Pot plants are quite wet-sensitively. Care must be taken with watering (Rot prone) and needs good drainage. Water sparingly during the growing season, keep very dry in winter.  Feed with a high potassium fertilizer  in summer.
Usually it is recommended to overwinter this plant in a bright and warm greenhouse with at least 8-10° C , but it proved to be quite frost resistant (if kept dry it hardy as low as -5° C)Outside full sun or afternoon shade, inside needs bright light, and some direct sun.
Some plants will offset readily, and clumps can be produced in a very few years.

Propagation: Direct  sow after last frost, cuttings or grafting.
 

An old specimen