List of Usnea species

This is a list of species in the fruticose lichen genus Usnea, commonly known as "beard lichens". As of March 2025^[update], Species Fungorum (in the Catalogue of Life) accepts 128 species of Usnea,^[1] although many more have been described throughout the genus's extensive taxonomic history. The fungal nomenclatural authority Index Fungorum lists nearly 2,000 taxa that have ever been associated with the genus, including forms, varieties, and subspecies, as well as numerous obsolete names, synonyms, misapplied names, and taxa temporarily placed in Usnea but later transferred to other genera.^[2] This significant discrepancy between accepted species and total published names reflects the complex taxonomic history of the genus. Ongoing revisions with molecular phylogenetics and morphological studies continue to refine the understanding of Usnea species boundaries.