Structure and identification
The stem is usually solitary, spherical or cylindrical, with a woolly sunken apex. Tubercles are elongated, pressed against the axis and become more pyramidal with age. Lower lateral spines are stronger and shorter, while upper ones are longer and gathered in a bundle. The dominant central spine projects and curves downwards. It may have several shorter companions. Flowers are yellow with a deep red throat. [Dicht and Lüthy 2005, p. 146–147]
Habitat and variation
The monograph documents sites in Coahuila, Nuevo León and Tamaulipas, on alluvial plains and limestone gravel at the eastern foot of Sierra Madre Oriental. The authors emphasise variation between populations and the gradual differentiation of armature during growth. These traits explain some historical differences in naming. [Dicht and Lüthy 2005, p. 146–147]
Related articles
Synonyms and names in the literature
Coryphantha borwigii · Coryphantha poselgeriana var. salinensis · Echinocactus salinensis · Mammillaria borwigii [2-WWW]