Allg. Gartenzeitung. 21: 94. 1853.
Plants many branched; branches 10–30 (–50). Roots thick taproots, large in upper portion. Stems subspheric, 4–5 × 5–8 cm, soft, flaccid; tubercles 12–25 × 5–8 mm; axils slightly short woolly, without bristles; cortex and pith not mucilaginous; latex absent. Spines 13–15 per areole, whitish to yellowish, glabrous; radial spines 12–14 per areole, gray, bristlelike, 6–9 × 0.1 mm, stiff; central spines 1 per areole, porrect, straight, not hooked or curved, similar to radial spines, 3–6 × 0.25 mm; subcentral spines 0. Flowers 4 × 5–7 cm; outermost tepal margins entire (or minutely toothed near base); inner tepals bright-yellow, paler near base, 20–30 × 4.5–8.5 mm; stigma lobes cream to pale-yellow, 5–6 mm. Fruits greenish white to dull pinkish tan or maroon, ovoid to short cylindric, 10–15 (–20) × 7 mm, juicy throughout; floral remnant weakly persistent. Seeds brown, 1.3 × 0.9 mm, pitted; testa soft or leathery, not hard or brittle; anticlinal cell-walls straight to slightly curved; interstices equal or narrower than pit diameters; pits bowl-shaped. 2n = 22.
Phenology: Flowering Jul; fruiting May.
Habitat: Tamaulipan thorn scrub on plains and low gravelly hills
Elevation: 0-300 m
Tex., Mexico (Nuevo León), Mexico (Tamaulipas)
A proposed taxonomic reduction of Mammillaria sphaerica to varietal rank within the geographically disjunct and morphologically distinct Mexican species, M. longimamma, while plausible, has not yet been convincingly justified.