Lichenized, Lichenicolous and Allied Genera

Lichenized genera are groups of fungi that engage in stable symbiotic relationships with photosynthetic partners—usually green algae or cyanobacteria—forming composite organisms known as lichens. These genera, primarily within the phyla Ascomycota and to a lesser extent Basidiomycota, represent a remarkable example of convergent evolution, where unrelated fungal lineages have independently evolved the ability to lichenize. Phylogenetic studies using multi-locus DNA sequencing have revealed that lichenization has evolved multiple times across the fungal tree of life, particularly in the classes Lecanoromycetes, Arthoniomycetes, and Agaricomycetes. These analyses have also clarified complex taxonomic relationships, helping to distinguish truly lichenized clades from non-lichenized or facultatively lichenized relatives.

Biogeographically, lichenized genera exhibit wide yet often discontinuous distributions, shaped by evolutionary history, dispersal mechanisms, climatic factors, and substrate specificity. Some genera, such as Cladonia and Lecanora, have cosmopolitan distributions and are found from polar regions to tropical forests, while others show strong endemism, restricted to specific continents, mountain systems, or microhabitats. Patterns of diversity in lichenized genera often reflect historical biogeography, such as post-glacial colonization, Gondwanan lineage splits, and orographic barriers. Understanding the phylogenetic relationships and distribution patterns of lichenized fungi provides critical insights into fungal evolution, symbiosis, and ecosystem adaptation in response to global environmental change.

Evernia