Taxonomic study of Physcia from Ningxia, China

Species diversity and geographic distribution of the genus Physcia in Ningxia were assessed through an integrated framework combining classical taxonomic identification, internal transcribed spacer (ITS)-based phylogenetic analysis of 147 specimens collected across multiple regions of Ningxia, and systematic evaluation of published records. A total of eight species were confirmed, namely Physcia adscendens H. Olivier., P. aipolia (Ehrh. ex Humb.) Fürnr., P. caesia (Hoffm.) Fürnr., P. grumosa K. N. Gao & D. L. Niu, P. leptalea (Ach.) DC., P. stellaris (L.) Nyl., P. tenella (Scop.) DC., and P. tribacia (Ach.) Nyl.. An identification key for Physcia species in Ningxia was established, with diagnostic morphological images and distribution data provided for all confirmed taxa. These findings enrich current knowledge of Physcia diversity in Ningxia, expand the regional taxonomic framework of the genus, and provide a foundation for further systematic and biogeographic investigation.