Fomitopsis officinalis (Vill.: Fr.) Bondartsev & Singer (Laricifomes officinalis) has a holarctic distribution in three large areas: West-Europe, North America, Ural-Siberia, and some small populations in Morocco (Maire, 1914; Malençon, 1955), China (Dai, 2000), Japan and Korea (Gilbertson & Ryvarden, 1986). Undoubtedly, the European as well as the West-Siberian populations are relicts, like their host populations, especially Larix spp. Branke (1896) suggested that the relict localities of F. officinalis on Larix deciduas Mill. in Poland can be recognized as evidence of continuous larch forest occupying large parts of the Europe during cold post-glacial periods. At present, the species is most common in Siberia from the foothills of the Ural Mountains to the shores of the Pacific Ocean (Murashkinskij, 1939; Bondartsev, 1953; Lyubarskij & Vassiljeva, 1975; Mikhaleva, 1993; Mukhin, 1993). It is rare also in North America (Overholts, 1953; Gilbertson, 1980).