Structure and identification
The stem is usually solitary, with fibrous roots, a dark green epidermis and a woolly, slightly sunken apex. Lateral spines spread over the tubercles, and their colour varies from horn-coloured to whitish. There may be zero to several central spines, varying in direction and curvature. The monograph describes large pale yellow flowers and elongated green fruits. The authors compared plants lacking central spines with the historical C. radians. [Dicht and Lüthy 2005, pp. 160–161]
Habitat and variation
The monograph documents a broad range in central Mexico, from Hidalgo and Querétaro to San Luis Potosí, Jalisco and eastern Zacatecas. Sites occur on plains and low hills with limestone gravel. Variation in armature also includes adult plants. Age, population and growing conditions together shape their appearance. [Dicht and Lüthy 2005, pp. 160–161]
Variation in internal structure
Coryphantha cornifera now includes the historical C. radians. In the 2023 anatomical study, the authors retained these names for two separate groups of material and sampled three adult plants from each. The group identified as C. cornifera came from Querétaro, and the group described as C. radians from San Luis Potosí. Retaining both identifications when describing the results allows differences between the plants actually examined to be traced. [Avila-Escobar et al. 2023, pp. 234–235, table 1. POWO, synonyms, 11 October 2026] [2-WWW]
In both groups, the hypodermis had two layers and contained druse crystal clusters. In material identified as C. cornifera, it was parenchymatous, while in material described as C. radians, its walls were unevenly thickened in a collenchymatous pattern. Stomata lay at the surface. The authors observed sunken stomata only at the stem base in the C. radians group. Both groups lacked mucilage cavities in the cortex, and xylem vessels were surrounded by wide-band tracheids. The differences concern the material examined from two sites. [Avila-Escobar et al. 2023, p. 235–239]
A separate 2016 study covered four adult plants described as C. radians. Vessel elements in tubercle bundles had smaller diameters than those in the central cylinder. This result complements the description of the conducting structure of the historical radians group, without extending it to every population of present-day C. cornifera. [Terrazas et al. 2016, p. 2, 6–8 PDF, tab. 1–2]
Related articles
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive. [Kaktologia 2009b, file p. 7] [Neciu b.d., file p. 1] [Cactáceas y Suculentas Mexicanas 1959, file p. 17]
Synonyms and names in the literature
Cactus cornifer · Cactus pfeifferianus · Cactus radians · Cactus radians var. pectinoides · Cactus scolymoides · Coryphantha bernalensis · Coryphantha cornifera var. scolymoides · Coryphantha cornuta · Coryphantha daimonoceras · Coryphantha impexicoma · Coryphantha maliterrarum · Coryphantha radians · Coryphantha radians var. impexicoma · Coryphantha radians var. pectinoides · Coryphantha schwarziana · Coryphantha scolymoides · Echinocactus cornifer · Echinocactus cornifer var. impexicomus · Echinocactus cornifer var. longisetus · Echinocactus cornifer var. muticus · Echinocactus cornifer var. nigricans · Echinocactus cornifer var. scolymoides · Echinocactus radicans · Mammillaria cornifera · Mammillaria cornifera f. scolymoides · Mammillaria cornifera var. impexicoma · Mammillaria cornifera var. mutica · Mammillaria cornuta · Mammillaria daemonoceras · Mammillaria daimonoceras · Mammillaria demonoceras var. impexicoma · Mammillaria impexicoma · Mammillaria pfeifferiana · Mammillaria pfeifferiana var. altissima · Mammillaria pfeifferiana var. dichotoma · Mammillaria pfeifferiana var. flaviceps · Mammillaria pfeifferiana var. fulvispina · Mammillaria pfeifferiana var. variabilis · Mammillaria radians · Mammillaria radians f. daimonoceras · Mammillaria radians f. impexicoma · Mammillaria radians var. daimonoceras · Mammillaria radians var. globosa · Mammillaria radians var. impexicoma · Mammillaria radians var. scolymoides · Mammillaria scolymoides · Mammillaria scolymoides var. longiseta · Mammillaria scolymoides var. nigricans · Mammillaria scolymoides var. raphidacantha [2-WWW]