Epithelantha polycephala

Name and distribution

Epithelantha polycephala is an accepted species from Coahuila, described in 1954 (in other treatments, E. micromeris var. polycephala, subsp. polycephala or E. greggii subsp. polycephala). [2-WWW]

Mountains and low rainfall

In the site-frequency analysis, E. polycephala was associated with fold mountains. Annual rainfall in the climate grid was among the lower values within the genus, as for E. greggii. This comparison shows a difference between species' environments at the maps' spatial scale of about 1 km². [Aquino et al. 2021, p. 4524–4527, ryc. 3–4]

The molecular study identified a major lineage including E. polycephala, E. greggii, E. pachyrhiza and E. pulchra. Soil and landform complemented the evolutionary comparison. Similar conditions at some sites coincided with close relatedness among the plants examined. [Aquino et al. 2021, p. 4522–4527, ryc. 2–4]

Thickened roots and wide areoles

In the 2019 key, Epithelantha polycephala had thickened roots, brown spines and areoles 0.90–1.80 mm wide. This combination distinguished it from the white-spined E. pachyrhiza with narrower areoles. Comparison with E. greggii revealed the root difference particularly clearly. The similarity of the above-ground stems required this organ to be considered during identification. [Aquino et al. 2019, p. 608, 610, 612; ryc. 5D–F]

Morphology was studied in 15 adult plants from three sites. The DNA samples formed a strongly supported distinct lineage. The name used in some earlier accounts, E. greggii subsp. polycephala, described plants recognised in this revision as a separate species. This treatment corresponds to the currently accepted name E. polycephala in POWO. [Aquino et al. 2019, pp. 605, 607–609, 612, POWO record, as of 11 October 2026] [2-WWW]

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