Beschreibung:
The paper presents the last part of the results of the short-term inventory of fungi species in the Biebrza National Park and synthesises all the data gathered during two surveys, including the information published by other authors. The main body of research is focused on a survey of macrofungi identified with morphology-based methods. In case of some specimens molecular technics have been applied. In total 346 macrofungal taxa (21 belonging to ascomycetes and 325 to basidiomycetes) were found during the survey, including 186 species unobserved during the previous inventory in 2012. As a result of previous and ongoing studies, the current number of macrofungi recorded from the Biebrza National Park reached 508 species. Among them eight taxa are newly reported for Poland (<em>Conocybe velutipes</em> var. <em>nitrophila</em>, <em>Entoloma caeruleum</em>, <em>E. plebejoides</em>, <em>Inocybe rennyi</em>, <em>I. vulpinella</em>, <em>Pholiota pityrodes</em>, <em>Pholiotina utricystidiata</em>, and <em>Tomentella pilosa</em>). The next seven species (<em>Bovista paludosa</em>, <em>Fistulina hepatica</em>, <em>Ganoderma lucidum</em>, <em>Geastrum schmidelii</em>, <em>Inonotus obliquus</em>, <em>Tulostoma kotlabae</em>, and <em>Xerocomus parasiticus</em>) are protected by law and 95 species belong to red-listed species. The results of two intensive, but relatively short-term survey clearly indicate the Biebrza National Park as a hot spot of macrofungi and suggest the need to undertake extended and regular inventories also in other Polish national parks.