Eirales

Eirales is an order of lichenized fungi within the class Lecanoromycetes. The order was formally described in 2018 following extensive molecular phylogenetic analyses of the Ascomycota. It currently comprises a single family, Eriaceae, which in turn includes several genera of crustose lichens that are commonly found on siliceous rock substrates in temperate and boreal regions. Species of Eirales are characterized by a relatively simple thallus structure, often lacking a clearly defined cortex, and by the production of fungal spores in asci that typically contain a small number of spores. Their photobiont partners are usually green algae of the genus Trebouxia. The order is distinguished from other lichenized lineages by unique genetic markers in the rpb1 and mtSSU loci, which have helped clarify its placement within the Lecanoromycetes. Eirales lichens frequently serve as bioindicators of air quality, particularly in urban and industrial environments where they exhibit sensitivity to sulfur dioxide and nitrogen oxides. Taxonomic research on Eirales continues to be active; new species are regularly described from Arctic and alpine ecosystems, expanding the known diversity and geographical range of the order.