Pachyphytum angustiflorum (Crassulaceae), una especie nueva de Guanajuato, México

Background and Aims: Pachyphytum is a genus of the Crassulaceae family, endemic to Mexico, where it is primarily distributed in the Bajío region. It comprises 25 species that tend to grow on rocky walls and most of them exhibit micro-endemic distributions. This study aims to describe and illus-trate a new species of Guanajuato state, assess its conservation status and present a distribution map.Methods: Live specimens of the new species were collected and analyzed in fresh to prepare the description. Subsequently, they are to be deposited in the herbaria CIIDIR, IBUG and ZON, while others are being maintained in cultivation in the IBUG living collection. Specialized literature was con-sulted to determine its morphologically closest species. In addition, the conservation status was assessed based on the IUCN Red List criteria. The distribution map was created using herbarium specimen data from the new taxon and related taxa.Key results:Pachyphytum angustiflorum is described as a species new to science, based on a comparative analysis including P. confusum, P. hookeri and P. viscidum, morphologically the most similar taxa. It is assessed as Critically Endangered (CR) due to its restricted distribution.Conclusions:Pachyphytum angustiflorum is endemic to the Barranca del Beato, municipality Tarimoro, Guanajuato, Mexico. The description of this species contributes to the knowledge of the high species richness and endemism of this genus.