Plants usually unbranched (or branches 2-3; branched profusely in cultivation), smooth. Roots diffuse or short taproots, largest roots basally 19-63 (average 33)% of greater stem diam. Stems deep-seated with only hemispheric apex protruding above ground level, spheric to cylindric, 1-2.7 × 0.6-1.7(-2.5) cm; tubercles 2-5 × 2-4 mm; areolar glands absent; parenchyma not mucilaginous; druses present in the stem and tubercle cortex (large lenticular druses absent); pith 1/5-1/3 of lesser stem diam.; medullary vascular system absent. Spines 15-28 per areole, appressed, lightly pigmented, pale tan to pinkish gray, weathering to gray, tips darker on some of largest spines, dark purplish brown to orange-brown, often partly overlain by an ephemeral whitish layer, peglike, not sharply needlelike, proximally compressed laterally; radial spines 13-24 per areole, 3.5-5 × 0.1-0.5 mm, radial/central distinction obscure; subcentral spines usually 1-4 in adaxial parts of areoles; outer central spines (1-)3(-4) per areole, in bird’s-foot arrangement at adaxial parts of clusters in adults, straight, inner central spines 0 per areole, longest spines 4-6 × 0.3-0.6 mm. Flowers nearly apical, 13-16 × 15-27 mm; outer tepals fringed; inner tepals 15 or 16 per flower, pale rose-pink to magenta, shading gradually to paler pink or white basally, sometimes with a darker midstripes distally but lacking well-defined midstripes, proximally whitish to pale yellow-green, 7-12 × 2.5-4 mm; outer filaments whitish to pale yellow-green; anthers yellow to orange-yellow; stigma lobes 4-8, green, 0.5-1.5 mm. Fruits green (sometimes slightly yellow tinted), spheric, obovoid, or obconic, 1.5-6 × 1.5-4 mm, nearly dry; floral remnant persistent but easily broken off. Seeds black, ± obovoid (to weakly pyriform), strophiole squarish, 0.8-1 mm, glossy, deeply pitted. 2n = 22.
|Nellie’s pincushion cactus|