Echeveria zoquitlanensis (Crassulaceae), a new microendemic species from Oaxaca, Mexico

Background: Echeveria (Crassulaceae) is an American genus distributed from Mexico to South America. The genus has 132 species recorded in Mexico, where the state of Oaxaca with 56 species has the greatest richness of the genus. The exploration of the high mountains of Santa María Zoquitlán led us to discover a population of Echeveria that differed from previously known species. Questions: Does the Echeveria population from the high areas of the municipality of Santa María Zoquitlán, Oaxaca represent a new species? Taxon: Echeveria species. Study site: Oaxaca Mountains, Mexico. Methods: Morphological comparison with the closely related taxa E. islasiae, E. longissima, E. longissima subsp. brachyantha, and E. longissima var. aztatlensis. Evaluation of conservation status based on the IUCN Red List categories and criteria. Results: We described and illustrated Echeveria zoquitlanensis from Santa María Zoquitlán, Oaxaca, Mexico as a new species. Due their long corollas and styles, the new species were placed in the series Longistylae, mapped its distribution, and determined its conservation status category as critically endangered (CR B1; B2). It differs from the other members of the series by its very long (up to 3.7 cm) crimson red homochromatic flowers, and pale pink to red pistils. Conclusions: Echeveria zoquitlanensis is the species with the largest flowers within the genus. Exploration carried out in isolated areas in Oaxaca favor the discovery of additional new species that would increase the large diversity of the state.