Epithelantha pulchra

Name and distribution

Epithelantha pulchra is an accepted species in POWO, native to Nuevo León. It was described in 2010 as E. pachyrhiza subsp. pulchra and transferred to species rank in 2019. [2-WWW]

Substrate and relatedness

In the 2021 study, E. pulchra sites were associated with luvic kastanozems. The same soil type showed an association with sites of E. spinosior, which belongs to the genus's other major lineage. Environmental similarity therefore did not correspond strictly to the division into two main groups of related species. [Aquino et al. 2021, p. 4524–4525, ryc. 2–3]

The tree based on four plastid DNA regions placed E. pulchra together with E. pachyrhiza, E. greggii and E. polycephala. The results concern material already recognised as a separate species, so the habitat observations retain a more precise identification than the shared former designation E. pachyrhiza. [Aquino et al. 2021, pp. 4522–4525, Fig. 2]

Round areoles with numerous spines

Adult Epithelantha pulchra plants in the 2019 revision had 40–55 spines per areole. Areoles were round, of similar length and width, and roots were thickened. The study covered 15 plants from three sites in Nuevo León. The high spine count together with areole shape distinguished this material from E. pachyrhiza with its elliptical areoles, under which it had formerly been classified as subsp. pulchra. [Aquino et al. 2019, p. 605, 608, 610–612; ryc. 5J–K]

Seeds of E. pulchra and of the E. pachyrhiza material examined had similar uneven multicellular sculpturing and expansions near the hilum region. Their samples nevertheless formed two strongly supported plastid lineages. In this analysis, E. pulchra was closer to E. greggii. Agreement between spine, areole and DNA data justified the combination at species rank published in 2019. [Aquino et al. 2019, p. 607–612; ryc. 3–5]

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