Jaapia argillacea produces scattered fruiting bodies composed of loosely intertwined hyphae. This fungus is largely distributed in the northern hemisphere and thrives in old grown forests, especially where admissible moisture levels exist. The genus Jaapia consists of only two species (J. argillacea and J. ochroleuca) and has sometimes been referred to as the sister to the Boletales. More recent findings indicate that Jaapia is sister to the rest of the Agaricomycetidae, which is the largest radiation of mushroom-forming fungi including approximately 15,000 species. Jaapia argillacea lives on decaying wood of conifers and is thought to produce a type of brown rot that has not been characterized in more detail. Nevertheless, the phylogenetic position of J. argillacea makes this fungus an excellent benchmark reference to evaluate evolutionary expansions and contractions of the enzymatic decay apparatus in all of Agaricomycetidae.
