Xerophyte

Habit

Simple at first. later often clustering.

Central Spines

4 to 15, bristle-like, 1-1,5(-2) cm long, reddish or pinkish brown, or yellowish, stouter than the radials.

Seeds

Reddish brown.

Description

Mammillaria spinosissimaSN|13783]]SN|13783]] is commonly cultivated around the world, often found in plant nurseries and private collections, and is nicknamed the “red-headed Irishman” because the most common cultivated forms have red or rust spine.

Tubercles

Very short, ovate conical, four-sided basally, 2 to 3 mm long; axils of tubercles setose but usually lacking bristles. Usually without latex.

Flowers

Flowers from the upper part of the plant in a ring shape around the apex, purplish or deep-pink, 12-20 mm long, 15 mm in diameter; inner perianth-segments acute; filaments much shorter than the perianth-segments, purple. Self fertile.

Blooming Season

Spring

Taxonomic

Mammillaria spinosissimaSN|13783]]SN|13783]] is a poorly known taxon, there are taxonomic uncertainties concerning its validity. It is very variable due to it's wide area of origin in Mexico and spines ranges in colour from white, to yellow, red or brown. There are several different subspecies and cultivars. Three subspecies are recognized, the nominate subspecies, subspecies pilcayensis (Bravo) D.R.Hunt and subspecies tepoxtlana D.R.Hunt.

Spines

Thin, needle-like, usually weak, hardly pungent, but variable.

Stem

Cylindrical, dark blue-green 7-30(-50) cm. long (2,5)6-7(-10) cm. in diameter, almost hidden under a dense covering of spines;

Radial Spines

20 to 26, straight, whitish, white to dirty white to yellow to deep reddish brown, 4-6(-10) mm long.

Fruits

Club shaped up to 20 mm long, greenish to dull purple.