Buglossoporus pulvinus, a rare wood-inhabiting fungus on ancient oak trees in Poland: ecology, distribution and extinction risk assessment

Buglossoporus pulvinus is widely distributed across Europe, within the range of Quercus robur. Throughout the area in which it appears, it is rare or very rare. It is listed as an endangered species in Europe and has been added to the Red Lists of fungi in a number of countries, along with awaiting inclusion in the IUCN Red List. In this study we have critically analysed the existing data about the occurrence of B. pulvinus in Poland. We have presented two new localities of the species in question in Poland, as well as new occurrences on the territory of the Białowieża National Park, the only place where this species had been previously recorded in Poland. Selected trees and logs inhabited by B. pulvinus have been characterized. We have indicated the number of observed basidiomata, their phenology, and the sizes of the largest specimens. We have identified 8 fungus species (Bisporella citrina, Daedalea quercina, Hapalopilus croceus, Hymenochaete rubiginosa, Laetiporus sulphureus, Mycena galericulata, M. inclinata, Xylobolus frustulatus) that coexist with B. pulvinus. Based on the new distribution data for B. pulvinus in Poland, according to IUCN Red List criteria this species should be classified as Endangered (EN).