First description: by W. Reppenhagen; Die Gattung Mammillaria: 169 - 171, 189 - 220; 1987
Body: Flattened, clumping, blue green body, 20 - 40 mm high and 40 - 70 mm in diameter.
Roots: Fibrous.
Sap: With latex.
Tubercule: Pyramidal, four angled, 12 - 14 mm long and wide.
Axil: Naked or with wool .
Radial spine: Absent.
Central spine: 4 - 6, 2 - 8 mm long, straight, smooth, glassy yellow to brownish with darker tip and thicker base.
Flower: Brownish yellow, 25 - 35 mm long and 30 - 35 mm in diameter, funnelform.
Fruit: Club-shaped, deep red, 20 - 25 mm long and 6 - 8 mm wide. Ripens 12 months after flowering.
Seed: Brown, club-shaped, 1,3 mm long and 0,8 mm wide. Hilum small, long, white and subbasal.
Habitat Substrate: On yellowish brown limestone hills.
Geographic Distribution: Mexico, Nuevo Leon, near Aramberri. Altitude 1350 m. Bibliography: Reppenhagen: Die Gattung Mammillaria. AfM - LBS Lieferung 09/94 Linzen.

Although Reppenhagen described M.crassimammillis from his collection of Repp1790, collected 2-2-81, he was not the first to find the plant. That honouor was given to Alfred Lau who collectd the plant on 26-11-74 as Lau 1069. I have not been able to discover wether Lau named the plant M.crassimammillis or was intending to given the plant a name before Reppenhagen's description.
The location for both of these collections is given has Aramberri at 1300m.
Reppenhagen later collected Repp2274 on 29-6-89. Location given has La Escondida at 1300m.
La Escondida is about 10km along the road heading west from Aramberri.
Michel Lacoste also visted the area and collected ML443 on the 22-4-93. Location given 5km of NL19, Aramberri-La Esconida at 1350m.
In 1997 David Hunt reduced crassimammillis to a subspecies of M.winterae saying that it could be a clustering form of M.wintreae. He also changed the name to ssp arramberri to reflect the plants location and also that Lau had found it first.
You rarely see plants or seed available. Koehres list seed of Lau 1069. They also indicate that the seed is from wild collected plants in cultivation. If that is the case and these mother plants are from Lau's original introduction in 1974, that would take them 34 years old, at the very lease.