{{Short description|Group of fungi}} [[File:Teranacaerulea.jpg|thumb|right|250px|The corticioid fungus ''Terana caerulea'', growing on the undersurface of dead branches]] The '''corticioid fungi''' are a group of fungi in the Basidiomycota typically having effused, smooth basidiocarps (fruit bodies) that are formed on the undersides of dead tree trunks or branches. They are sometimes colloquially called '''crust fungi''' or '''patch fungi'''. Originally such fungi were referred to the genus ''Corticium'' ("corticioid" means ''Corticium''-like) and subsequently to the family ''Corticiaceae'', but it is now known that all corticioid species are not necessarily closely related. The fact that they look similar is an example of convergent evolution. Since they are often studied as a group, it is convenient to retain the informal (non-taxonomic) name of "corticioid fungi" and this term is frequently used in research papers<ref name = Larsson>Larsson K-H, Larsson E, Koljalg U. (2004). High phylogenetic diversity among corticioid homobasidiomycetes. ''Mycological Research'' '''108''': 983–1002.</ref> and other texts.
==History== The genus ''Corticium'' was established by Persoon in 1794 for fungi having smooth, effused fruit bodies. ''Corticium roseum'' Pers. was later selected as the type species.<ref>Donk MA. (1963). The generic names proposed for Hymenomycetes XIII. ''Taxon'' '''12''': 158-159.</ref> Subsequent authors described over 1000 species in the genus<ref>{{cite web|url=http://www.indexfungorum.org/Names/names.asp?strGenus=Corticium|title=Index Fungorum - Search Page|website=www.indexfungorum.org|access-date=19 April 2018}}</ref> which continued to be used in its wide sense up until the 1950s. Though a number of genera had been recognized as distinct from ''Corticium'' from the late nineteenth century onwards, it was not until Swedish mycologist Prof. John Eriksson reviewed the corticioid fungi in a series of publications starting in 1950<ref>Eriksson J. (1950). ''Peniophora sect. Coloratae''. Uppsala</ref><ref>Eriksson J. (1958). ''Studies in the Heterobasidiomycetes and Homobasidiomycetes-Aphyllophorales of Muddus National Park in Sweden''. Uppsala.</ref> that modern concepts were formed. The eight-volume work that he initiated, ''Corticiaceae of North Europe'' (1973-1987), effectively established the current circumscription of the corticioid fungi.
Eriksson and his co-authors, however, still placed all or most of these fungi within the ''Corticiaceae'', though stating that this was "not a natural taxon but an assemblage of species with similar habitat."<ref name = Hjort>Hjortstam K, Larsson K-H, Ryvarden L. (1987). ''The Corticiaceae of North Europe''. Vol. 1. Oslo: Fungiflora {{ISBN|82-90724-03-9}}</ref> It was not until the advent of DNA sequencing that the full diversity of these fungi was realized.<ref name = Larsson/><ref>Binder M. et al. (2005). The phylogenetic distribution of resupinate forms across the major clades of mushroom-forming fungi (Homobasidiomycetes). ''Systematics and Biodiversity'' '''3''': 113–157.</ref> The genus ''Corticium'' is still retained, but is now restricted to a few species closely related to the type. The ''Corticiaceae'' is now equally restricted to a few genera close to (and including) ''Corticium''. Crust-like species are found in no less than 18 of the 24 currently recognized orders of higher basidiomycetes (Agaricomycotina).<ref>Hibbett D et al. (2007) A higher-level phylogenetic classification of the ''Fungi''. ''Mycological Research'' '''111''': 509-547.</ref><ref>Larsson K-H. (2007). Re-thinking the classification of corticioid fungi. ''Mycological Research'' '''111''': 1040-1063.</ref><ref>Binder M et al. (2010). Amylocorticiales ord. nov. and Jaapiales ord. nov.: Early diverging clades of Agaricomycetidae dominated by corticioid forms. ''Mycologia'' '''102''': 865-880.</ref>
==Description and diversity== [[File:Hyphodontia sambuci Eglinton.JPG|thumb|left|250px|The corticioid fungus ''Lyomyces sambuci'', common on dead elder branches]] [[File:Stereum Hirsutum02.jpg|thumb|right|250px|The corticioid fungus ''Stereum hirsutum'', showing an effused fruit body with bracket-like outgrowths]] Corticioid fungi are rather loosely defined, but most have effused fruit bodies, the spore bearing surface typically being smooth to granular or spiny. Some species (in the genera ''Stereum'' and ''Steccherinum'', for example) may form fruit bodies that are partly bracket- or shelf-like with a smooth to spiny undersurface.<ref name = Hjort/>
The corticioid fungi currently comprise around 1700 species worldwide, distributed amongst some 250 genera.<ref>Hjortstam K. (1998) A checklist to genera and species of corticioid fungi. ''Windahlia'' '''23''': 1–54.</ref> They constitute around 13% of the homobasidiomycetes known to date.<ref name = Larsson/>
==Habitat and distribution== Most corticioid fungi are wood-rotting species and rely on wood degradation as their primary means of nutrition. Although the fruiting bodies are formed on the underside of dead branches or logs, the fungus resides within the wood. A number of species are litter-rotting and produce fruitbodies underneath fallen leaves and compacted litter as well as on fallen wood. Some of these species are known to be ectomycorrhizal (forming a beneficial association with the roots of living trees). A few specialist species grow on dead herbaceous stems and leaves or on dead grass, rush, and sedge stems, especially in marshes. Parasites of plants and other fungi are also found in the group.
Corticioid fungi have a worldwide distribution, but are commonest in forest communities.
==References== {{reflist}}
Category:Basidiomycota Category:Fungal fruiting body types