Xerophyte

Habit

Solitary or clustering cylindrical cactus entirely hidden under the many closely set spines.

Central Spines

About 6, , a little longer and stouter than the radials, slightly spreading, white with brown tips, 8-10 mm long.

Seeds

Nearly round, black, with a projection at base and a large basal hilum.

Description

Mammillaria sleviniiSN|5348]]SN|5352]] is synonymous of Mammillaria albicansSN|5352]]SN|5348]], they are are very similar, namely size and form of stems, shape of spines, flowers, etc. and the two plants are not readily distinguishable if not for the stems, simple or few branched (1-10 compared to 5-15 branched in M. albicans) moreover it has darker spines and the spine-areoles are not densely lanate.

Tubercles

Broadly conical, without latex. The axil is woolly, especially in the flowering zone and bears few bristles, white with dark brown tips.

Flowers

Around the top, white to pale pink, with pinkish mid-veins, up to 20 mm in diameter. Outer perianth-segments with a pinkish mid-rib. Inner perianth-segments white. Filaments pinkish. Style nearly white; stigma-lobes nearly white to purplish.

Blooming Season

Summer (June to August).

Spines

At top of plant pinkish below, with brown to blackish tips, on lower part of plant bleaching white.

Stem

Columnar, pale green, up to 10 or more cm tall, 5-6 cm in diameter branching basally

Radial Spines

14-21, white, 5 - 8 mm long.

Fruits

Club-shaped, red, 10-18 mm long.