Xerophyte

Habit

It is tiny soft-bodied cactus species with short, white dense spines growing parallel to the stem, partially hiding it. Its central spines are few, long, dark and hooked. The stem is simple, usually unbranched.

Central Spines

(1-)2-4 stouter than the radials, sometimes 2 or 3 hooked at apex stiffly spreading 10-12 mm long, dark brown to black in colour.

Seeds

Black, ovate with a ventral hilum.

Description

Mammillaria wrightii var. wolfiiSN|9411]]SN|12943]] is one of the geographical forms of the morphological variable Mammillaria wrightiiSN|12943]]SN|9411]] which distinguishes for its huge, translucent white flowers instead of magenta/purple.

Phenology

It flowers in summer and fruits during the autumn.

Tubercles

Cylindrical, terete, flaccid, without latex, 10-15 mm long and 3-4 mm wide, with naked axils.

Flowers

Large for a Mammillaria, and white, up to 6 cm in diameter when expanded. The outer perianth-segments lanceolate, about 12 mm long, externally greenish, prominently fringed; inner perianth-segments lanceolate, to 30 mm long and 4 mm wide, entire, pointed, translucent white often whit a very pale maroon-purple midvein toward the tips. Perianth parts reflexed. Filaments glassy white, rarely pinkish, anthers bright yellow. The style is very pale greenish, supporting 7-11 stigma lobes that are green.

Stem

Depressed-globose, or (rarely) short cylindrical with age, dull green, 4-10 cm tall, 4-8 cm across, aboveground when expanded during moist periods, but during drought periods the stems become flat-topped and shrink to ground level.

Radial Spines

Usually 10-14, spreading, acicular, 8-12 mm long, appressed against the stem, slightly downy, lateral ones a little longer white and dark tipped, or the 3 upper ones considerably thicker and shorter, often with darker upper part. are brownish throughout

Fruits

Globose or ovoid, usually 25-35 mm in diameter, with translucent purple-green pericarp and a green juicy aromatic flesh.

Areoles

Circular about 2 mm broad, with short white hairs, later naked.