Lapland 2. An annotated checklist of the polypores of northeastern Finland.-Karstenia 31:13-28. Seventy-seven polypores are listed from virgin forests in northeastern Finland, ten of which are classified as threatened in Finland. The host range and abundance of each species are given. The occurrences of threatened and also some abundant species are treated with special reference to their distribution and habitat ecology. Fungal species compositions of spruce, pine and birch forests are compared: 33 species were recorded growing on Picea abies subsp. obovata, 31 species on Pinus sylvesrris and 24 species on Betula pubescens. The economically most harmful pathogenic polypores found in the swdy area were Climacocystis borealis (Fr.

Basidiomycetes, especially the wood-inhabiting fungi, were studied in the Vlirrio Strict Nature Reserve, the Urho Kekkonen National Park and adjacent areas in Finnish East Lapland, which contain some of the last remnants or primeval, Northern Boreal forest at and near the alpine and polar timberline. The qualitative and quantitative composition of the fungi, as indicated by their fruit body production, was studied in naturally regenerating virgin forests and the area of a fairly recent forest fire, special attention being paid both to species recognized as threatened in Finland and to potentially threatened fungi. The area is also affected by long-distance air pollution from the mining and metal industry in the western Munnansk Region, Russia. The main woody plants decayed by basidiomycetes in the region are Pinus sylvestris L., Picea abies (L.) Karsten subsp. obovata (Ledeb.) Domin and Betula pubescens Ehrh. subsp. czerepanovii (Orlova) Hlimet-Ahti. A general biogeographical and ecological outline of the study area is presented.