Xerophyte

Habit

The stem of this jewel is simple usually unbranched,.

Central Spines

usually 2-3 (less often 1-4 or more) , stouter than the radials, sometimes 2 or 3 hooked at apex stiffly spreading (6-)12-14(-20) mm long, reddish-brown, black or black-and-white.

Seeds

Black, pitted, and 1,3-1,5 mm long, with a narrow ventral hilum

Description

Mammillaria wrightiiSN|9411]]SN|9411]] 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. Wondrous flowers, large and red-purple to magenta, appear in late summer followed by large palatable, grape-shaped fruits.

Immature Specimens

Young seedlings may have only one hooked central spine per areole and at least two hooked centrals per areole usually are present in juveniles specimens with a stem diameter of more than 1 cm.

Phenology

In general Mammillaria wrightiiSN|9411]]SN|9411]] flowers in habitat in the summer following rains and fruits during the autumn.

Tubercles

Cylindrical, terete, flaccid, without latex, up to 12 mm long, with naked axils.

Flowers

Large for a Mammillaria, rose-purple or magenta (rarely white), typically 2,5-4 cm long and 2,5-7,5 cm in diameter when expanded. The outer perianth-segments about 13, triangular-obtuse, prominently fringed; inner perianth-segments bright purple. Perianth parts reflexed.The anthers are bright yellow. The style is greenish, pinkish above, supporting 7-11 stigma lobes that are yellow or pale green, or rarely reddish.

Stem

Depressed-globose, to short cylindrical, dark green, 3-8 cm in diameter and 4-8 cm tall aboveground when expanded during moist periods, but during drought periods the stems become flat-topped and shrink to ground level, in part the result of a prolonged underground base.

Radial Spines

Usually 8-15, spreading, acicular, 5-10 mm long, appressed against the stmem, upper and lateral ones a little longer white and dark tipped, or the upper radials are brownish throughout

Fruits

Globose or ovoid, previously described as "grapelike," usually are 1,3-2 cm long and 12-25 mm in diameter, green or dull purple, very juicy, and differ conspicuously from the elongate, bright red mature fruits of Mammillaria grahamiiSN|9189]]SN|9189]].

Areoles

Circular with short white hairs.