Peperomia accentus (Piperaceae), a new geophytic species endemic to the Sierra Madre Occidental, Mexico

Peperomia accentus is described and illustrated as a new species of Piperaceae from the state of Zacatecas, Mexico, in the Sierra Madre Occidental mountain range. This new taxon belongs to the subgenus Tildenia, which includes species characterized by their geophytic habit. It can be distinguished from its congeners mainly by the combination of roots at the apex of the globose tuber, peltate leaves, numerous simple inflorescences and flowers with long and geniculated styles of a reddish color. A preliminary threat assessment is provided for the new species based on IUCN Red List guidelines. We provide a comprehensive analysis of the distribution patterns of the Mesoamerican species of Peperomia subgenus Tildenia. Finally, we include a key for species distributed north of the Trans-Mexican Volcanic Belt.