Basidiomycetes at the timberline in Lapland 4. Postia lateritia n. sp. and its rust-coloured relatives

Abstract

The taxonomy of the Postia fragilis group (polypores, Basidiomycetes) is revised and three species are recognized in North Europe: P. fragilis (Fr.) Jul., P. leucomallella (Murr.) Jul. and P. lateritia Renvall n. sp. The species are described and illustrated, and the Finnish distributions are mapped. The first two species are widespread in Europe and in North America. P. lateritia is a saprotrophic polypore here reported from Finland, Sweden and Canada. It is associated with a brown rot and has been found almost exclusively on decorticated windfalls of Pinus sylvestris L. in old forests of coniferous trees. A neotype is selected for Polyporus fragilis Fr. and the status of the genus Postia Fr. is reviewed and it is considered to be validly published; the genus Oligoporus Bref. is accepted in a restricted sense to comprise species which have short and often cyanophilous spores and which tend to produce chlamydospores. The new combination Postia septentrionalis (Vampola) Renvall is proposed and the identity of Leptoporus lowei Pilat (Oligoporus lowei (Pilat) Gilb. and Ryv.) is discussed.