Xerophyte

Central Spines

1 to 4, mostly 1, needle like, one hooked (occasionally straight), smooth, brown to black, 2-14 mm long (short about 2 mm long in var. gueldemanniana and 10 or more mm long in var. guirocombensis).

Sap

Without latex.

Seeds

Spherical, black, 1 mm long and 0,8 mm wide, ventral hilum. Selfsterile.

Description

Mammillaria gueldemannianaSN|8816]]SN|8836]] is clumping mammillaria species that becomes shrublike by putting out numerous basal shoots. It is generally included within (as a synonym of) Mammillaria sheldoniiSN|8836]]SN|8816]], suggesting that there is not really a fundamental difference between the two (aside from bigger flowers for M. gueldemanniana, not many differences), and hard to name accurately without knowing where they come from, and there remains a considerable confusion surrounding the true identity of this this plant.

Phenology

It blooms several times a year in summer. The fruit ripens about one year after flowering.

Roots

Fibrous.

Tubercles

Cylindrical, closely set, soft to rather firm and fleshy, rounded toward the apex and quadrangular, wide and glabrous at the base, keeled ventrally, 7-12 mm long and 5-8 mm wide. Axil mostly naked.

Flowers

Funnelform to broad funnelform, 18–25 mm long and 16–35 mm in diameter, carmine pink with a crimson throat. (The flowers are bigger and open wider in var. guirocombensis)

Stem

Strongly clumping, globular at first, becoming cylindrical to columnar, somewhat sunken apex, stems light grey-green, spines nearly obscuring the stem, 10-20 cm high and 3-5 cm in diameter.

Radial Spines

12-22, slender, straight, needle like to bristle like, smooth, spread out horizontally, whitish with brown tip about 5 mm long.

Fruits

Club-shaped, scarlet-red, small 10-25 mm long and 4-7 mm wide.