Lichenomycetes

Lichenomycetes is a class of fungi within the Basidiomycota that forms lichens through a symbiotic association with photosynthetic partners, typically green algae. In these lichens, the fungal partner is a basidiomycete, making them basidiolichens, a minority among lichen-forming fungi whose partners are usually ascomycetes. The group represents a distinct lineage recognized by modern molecular analyses and includes several genera with described species.

Lichenomycetes occur in a variety of habitats, including soils, moss cushions, and rock surfaces, often in cool or temperate regions and in alpine or polar environments. The photobiont partner is predominantly green algae, with cyanobacteria occurring less frequently in some lineages. The thallus ranges from crustose to small foliose forms and is composed of fungal hyphae intimately associated with photobiont cells, enabling mutual exchange of nutrients.

Reproduction in Lichenomycetes follows basidiomycete patterns: the fungal component produces basidiospores on basidia, contributing to sexual dispersal. Some members can also exhibit yeast-like growth when free-living, and asexual propagation of the lichen thallus via fragmentation can occur.

Taxonomy and research on Lichenomycetes have been shaped by molecular phylogenetics, which support its status as a distinct clade within Basidiomycota. Ongoing studies continue to refine its genera, species boundaries, and the specifics of photobiont associations. Lichenomycetes provides insight into the diversity of lichen symbioses and the evolutionary pathways of basidiomycete fungi.