Studies in the Phaeotremella foliacea group (Tremellomycetes, Basidiomycota)

The taxonomy of the Phaeotremella foliacea group is revised based on morphological, ecological, geographic and DNA data. The name P. foliacea is retained for the gymnosperm-dwelling species associated with Stereum sanguinolentum in Eurasia and North America. Tremella neofoliacea and Cryptococcus skinneri are considered synonyms of P. foliacea s. str. Three other species in the complex inhabit deciduous trees. Of them, Phaeotremella fimbriata, comb. nov., is associated with Stereum rugosum; this species possesses blackening basidiocarps and small basidiospores, and it occurs in Europe. Its close relative is the East Asian Phaeotremella eugeniae, sp. nov., inhabiting Quercus mongolica and having larger basidiospores. The third species, Phaeotremella frondosa, comb. nov., produces the largest basidiospores in the genus and is associated either with S. rugosum (mainly in North Europe) or with other Stereum species (temperate Eurasia and North America). Additionally, Tremella nigrescens is typified and placed in the synonyms of P. frondosa, and two species, T. fuscosuccinea and T. roseotincta, are combined to Phaeotremella.