An assessment of the taxonomy and chemotaxonomy of Ganoderma

The taxonomic and nomenclatural history of the genus Ganoderma and related basidiomycetes is reviewed and compared to recent studies on its molecular phylogeny. A basidiomycete belonging to the genus Ganoderma can often rather easily be recognised in the field from the macro-morphological characters of the sporocarp. The most important species and lineages can also be discriminated well by molecular phylogeny. However, the application of incongruent species concepts and the frequent misapplication of European names by chemists and other non-taxonomists have created confusion in the scientific literature. The identity of the species reported in the course of mycochemical studies can often not be verified, since no voucher material was retained. In this review, an overview on the most important types of specific chemotaxonomic traits (i.e., secondary metabolites of the basidiomes and mycelia) reported from the genus is provided. Albeit certain triterpenoids such as ganoderic and lucidenic acids, steroids (e.g. ergosterol) and triterpenes (e.g. friedelin) appear to have some chemotaxonomic value at the generic rank, their relevance for species discrimination remains to be assessed. We propose that all important names in Ganoderma should be, as required, epitypified by fresh collections for which living cultures should be made available and that these should be examined by a combination of morphological, chemotaxonomic and molecular phylogenetic methods to attain a more stable taxonomy.