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.[6]
The corticioid fungi currently comprise around 1700 species worldwide, distributed amongst some 250 genera.[11] They constitute around 13% of the homobasidiomycetes known to date.[1]