Xerophyte

Habit

Plants usually solitary, sometimes forming clumps.

Central Spines

4 in a cross formation, whitish, pale grey or slightly reddish, with brown tips, stout, needle-like, straight or slightly curved, the longest, up to 30(-45) mm, are the upper and lower, the two side ones only to half that length.

Sap

With latex.

Seeds

Brown.

Description

Mammillaria winteraeSN|11888]]SN|11888]] is a spherical cactus species that grows flatted to the ground with a solitary body attaining a large size (up to 30 cm in diameter) and is one of the largest Mammillaria. It is a very distinctive plant with large, angled tubercles decorated by rings of pale greenish-yellow blooms.

Tubercles

Large, four-angled, keeled, with latex. The axils that are at first naked, but later develop dense white wool, but without bristles. Parastichy number 8-13.

Flowers

Quite large, yellowish white or greenish yellow in colour, up to 3 cm long and almost as wide. Inner perianth segments yellowish-white or greenish-white with sulphur yellow midveins, outer perianth segments brownish red with broad yellowish white margins,

Chromosome Number

2n = 22.

Stem

Hemispherical to depressed globose, light green to blue green, 20-30 cm in diameter.

Radial Spines

Absent.

Fruits

Club shaped, pale red.