wapiti3:Dictyonema sericeum on Flickr. Via Flickr: Evolutionary relationships and lichenization The
wapiti3: Dictyonema sericeum on Flickr. Via Flickr: Evolutionary relationships and lichenization The Dictyonema fungus is a basidiomycete, so it discovered lichenization independently from the ascomycete lichens. Within the basidiomycetes, Dictyonema is closely related to three other genera of basidiolichens that are also in the family Hygrophoraceae: Lichenomphalia, Acantholichen, and Cyphellostereum. Interestingly, molecular data indicates that lichenization has evolved independently at least twice, and perhaps three times, within these four genera, which suggests that for some reason the fungi in Hygrophoraceae are predisposed to evolve into lichens. The majority of the other, non-lichenized fungi in this family are saprotrophic (consuming decaying organic matter) or ectomycorrhizal (symbiotic with plant roots), although numerous species, such as Arrhenia, grow on mosses and derive nutrition from them. It is not yet understood why these fungi are more inclined to become lichens -- source link