Pleopsidium

Pleopsidium is a genus of lichen-forming fungi in the family Acarosporaceae (order Acarosporales). The widespread genus was circumscribed by lichenologist Gustav Wilhelm Körber in 1855. After a 2025 revision of the genus, it comprises eight species.

==Taxonomy== In 2025, a taxonomic revision of the genus from China clarified species limits and expanded the genus's recognised diversity. Based on combined morphological, chemical and DNA sequence data, the authors identified a lineage of species lacking characteristic fatty acids and formally described two new taxa, Pleopsidium tumidulum and P. corrugatulum. These new species, together with P. gobiense, form a strongly supported clade distinct from other fatty acid‑containing members of the genus. The revision provides updated diagnostic characters and phylogenetic context to improve identification and classification of Pleopsidium species.