Stem tubercles 8-24 mm. Radial spines usually 8-15 per areole. Flowers 2.5-7.5 cm diam. Fruits 12.5-26 mm diam. Flowering summer; fruiting fall. Semidesert grasslands, plains grasslands, pinyon-juniper woodlands, gentle slopes, mesas, valleys, usually on alluvial or igneous substrates; 1200-2100(-3000) m; Ariz., N.Mex., Tex. Mammillaria wrightii var. wrightii is sometimes sympatric with M. viridiflora, but usually occupies deeper soils.
Benson 1982, FNA 2003
Common Name: Wright's nipple cactus Duration: Perennial Protected Status: Salvage restricted status in Arizona. General: Low globose cactus that is usually unbranched stems with tubercles 8-24 mm, the stem spheric or flat-topped. Spines: Radial spines 8-15, these straight and wrapping parallel around stem with 1-5 hooked central spines. Flowers: Flower 25-75 mm diameter with fringed outer tepals and inner tepals that are rose-pink or magenta and lanceolate linear and spreading widely to form a shallow bowl, the anthers are yellow, the style reddish-purple to green, and the flowers form a circle near the stem apex. Fruits: Fruits dull purple or green and spheric to obvoid, 12.5 -26 mm diameter and juicy throughout, while the floral remnants are persistent. Ecology: Found in semi-desert grasslands, plains grasslands, woodlands, steep, gentle slopes, mesas, and valleys, on alluvial or igneous substances from 5,000-8,000 ft (1524-1676 m), flowers summer, fruits fall. Notes: Appears similar to M. wrightii var. wilcoxii, except that it generally has a lesser number of radial spines, ( 8-15). Also, flowers and fruits generally larger than var. wilcoxii, (fruits 12.5-26 mm). This variety appears to prefer higher elevations. Considered rare in many counties in Arizona. M. wrightii var. wrightii is sometimes sympatric was M. viridiflora, but usually occupies deeper soils. Ethnobotany: Specific use of variety is unknown, however the stems and ripe fruit of the genus were used as food. Etymology: Mammillaria comes from the Latin mammilla, a nipple, while wrightii is named after Charles Wright (1811-1855), an American botantical collector who collected plants for Professor Asa Gray at Harvard, and later worked on the Mexican Boundary Survey, collecting plants for Professor John Torrey. Synonyms: Mammallaria meridiorosei Editor: LCrumbacher, 2010