The endemic Mexican taxa have relatively large flowers like those of Epithelantha bokei.

FNA 2003, Benson 1982

Common Name: pingpong ball cactus Duration: Perennial Protected Status: Salvage restriced status in Arizona. General: Miniature and erect but usually unbranched and mostly spheric, this tiny plant is often flat-topped and 3-4.5 cm long by 1-6 cm in diameter with numerous tubercles and spines obscuring the stem, areoles are typically about 2 mm apart with the stem typically not deep-seated in substrate. Spines: Spines 20-90 per areole and accompanied by white woolly hairs in 1-5 series and appressed on sides of stems, these erect at stem apex but not distinguishable as central or radial spines. Flowers: Flowers diurnal and borne along adaxial margins of spine clusters but usually obscured by the long spines the stem apex, they are 3-4.5 mm diameter and up to 6+ mm long, funnelform with pale pink tepals that are 1 mm long and broad, the filaments are tinged with red and the anthers white to pale yellow. Fruits: Fruits indehiscent and bright red but narrowly cylindric and fleshy at maturity, 3-12 mm long by 1.5-6 mm diameter. Ecology: Found on limestone or sometimes igneous soils of rocky hills and ridges in deserts and grasslands from 3,500-5,000 ft (1067-1524 m). Notes: This species is considered rare in Cochise county. Ethnobotany: Unknown Etymology: Unknown Synonyms: Mammillaria micromeris Editor: SBuckley, 2010