Name and distribution
Epithelantha greggii is an accepted species from Coahuila in Mexico. The current combination was published in 1926 (earlier, and in some later treatments, E. micromeris var. greggii or subsp. greggii). The former subsp. potosina is now the accepted species E. potosina. [2-WWW]
Foothill zones and a dry environment
In the analysis of site maps, E. greggii showed an association with foothill zones. The climate of its sites, like those of E. polycephala, had lower annual rainfall than the environments of some other species in the genus. The data come from climate and topographic grids linked to georeferenced observations. [Aquino et al. 2021, p. 4524–4527, ryc. 3–4]
Relatedness and seed chemistry
In the tree obtained from four plastid DNA regions, E. greggii belonged to a major lineage also including E. pachyrhiza, E. polycephala and E. pulchra. This division presents the result of a molecular analysis covering all ten recognised species. [Aquino et al. 2021, pp. 4522–4525, Fig. 2]
In Chen and colleagues' study of seed walls, both E. greggii and E. micromeris showed no detectable lignin in thioacidolysis and NMR. The result identifies the chemical composition of the seeds examined, without determining their germination capacity or drought resistance. [Chen et al. 2013, p. 203–206]
Slender roots and spine variation
Among 45 adult plants from nine sites, Epithelantha greggii material had 19–30 spines per areole and flowers 12.1–13.6 mm long. Areoles in the key were round, 1.15–1.50 mm wide. Ordinary slender roots distinguished these plants from E. polycephala, in which they were distinctly thickened. Stem and spine size and colour were considered together with root and seed traits. [Aquino et al. 2019, p. 605, 608, 610, 612; tabela 5, ryc. 5D–F]
Plants initially identified as E. densispina and E. rufispina fell within the morphological range of E. greggii and belonged to the same plastid lineage. The revision included both names in E. greggii, consistent with their current treatment in POWO. E. potosina, formerly a subspecies of E. greggii, belonged to a different major lineage and was raised to species rank. [Aquino et al. 2019, pp. 606, 608, 611–612, POWO synonyms, as of 11 October 2026] [2-WWW]
Related articles
Materials from the author's archive
The species also appears in Konrad Szychowski's private material archive. [Kaktologia 2009b, file p. 8] [Neciu b.d., file p. 1]
Synonyms and names in the literature
Epithelantha micromeris var. greggii · Epithelantha micromeris subsp. greggii · Cactus micromeris var. greggii · Cephalomamillaria greggii · Cephalomamillaria micromeris var. greggii · Epithelantha densispina · Epithelantha micromeris var. densispina · Epithelantha micromeris var. rufispina · Epithelantha rufispina · Mammillaria greggii · Mammillaria micromeris var. greggii [2-WWW]