Coryphantha hesteri

Plants unbranched, except in old age, ultimately forming dense clumps, 5-20(-30) cm diam., stem not obscured by spines when hydrated, obscured when desic-cated. Roots short, fleshy, enlarged taproots, basally ± ¹/3-¹/2 of stem diam. Stems deep-seated, aerial parts inconspicuous, flat-topped to hemispheric (to ovoid or spheric in horticulture), almost completely withdrawing into substrate when desiccated, (2.4-)5-9 × 1.5-4.7 cm, above-ground portion 1-6.5(-9); tubercles 5-9(-12) × 4-6(-7) mm; areolar glands absent; parenchyma not mucilaginous; druses present, largest druses lenticular, 0.3-0.5 mm diam.; pith ¹/5-¹/3 of lesser stem diam.; medullary vascular system not recorded. Spines (12-)15-20(-25) per areole, white with brown tips (quickly weathering to gray) or the adaxial spines per areole dark gray-brown throughout; all radial spines or 1-3 adaxial spines sometimes interpreted as central, laterally compressed at base, 6-13 × (0.1-)0.2-0.3 mm; subcentral spines 0(-3) per areole; central spines 0(-3) per areole, appressed, straight, ± equal, 9.5-13(-15) × 0.2-0.3 mm. Flowers nearly apical, 18-25 × 20-34 mm; outer tepals fringed; inner tepals 22-27 per flower, bright rose-pink or magenta, proximally paler, 10-17 × 2-4 mm; outer filaments colorless or white to rose; anthers orange-yellow; stigma lobes (4-)5-6(-7), white, cream, or pale pink, 1-3 mm. Fruits green, spheric or obovoid, (3.5-) 5-8(-10) × 3-6 mm, quickly drying; floral remnant usually persistent. Seeds dark brown, spheric, 0.9-1.1(-1.2) mm, pitted. 2n = 22.

Flowering Apr-Jun(-Nov); fruiting Aug-Oct(-Jan). Semidesert grasslands, oak-juniper-pinyon woodlands, rock crevices, rocky soils, sandstone, limestone, igneous substrates, novaculite; of conservation concern; 1200-1600 m; Tex.

Coryphantha hesteri resembles C. vivipara but is much smaller in all parts. Coryphantha hesteri is characteristic of the dwarf cacti on novaculite outcrops but is not limited to that substrate.