The impacts of the discontinuation of dual nomenclature of pleomorphic fungi: the trivial facts, problems, and strategies.

The symposium "One fungus = Which name" held in Amsterdam 12-13 April 2012, addressed the drastic changes in the naming of pleomorphic fungi adopted by the 18(th) International Botanical Congress in Melbourne in 2011. Possible solutions and ways to face resulting problems were suggested. The fundamental change is that under the new rules fungi in future will be treated nomenclaturally like plants and all other groups of organisms ruled by the ICN, i.e. with one correct name for each species. Numerous discussions and statements during the Symposium reflected widespread anxieties that these rules could negatively influence taxonomic work on pleomorphic fungi. However, they are groundless, being based on misunderstandings and confusion of nomenclature and taxonomy. With pleomorphic fungi, taxonomists will in future have to answer the question whether different morphs can represent one fungus (taxon), but this remains a taxonomic decision and has nothing to do with nomenclature. Furthermore, the ICN does not and cannot rule on how this decision is made. Thus it cannot provide rules based solely on methods involving morphology in vivo or in vitro, molecular analyses, physiological and biochemical data, inoculation experiments in pathogenic groups or any other methods or combinations of them. It is up to the taxonomist to select appropriate methods and to decide which data are sufficient to introduce new taxa. Some future problems and strategies around the application of anamorph- and teleomoph-typified taxon names (genera and species), are discussed here, using the recently monographed powdery mildews (Erysiphales) as an example.