Basidiomycetes at the timberline in Lapland 3. Two new boreal polypores with intricate hyphal systems

Abstract

Two new saprotrophic polypore species, Antrodia primaeva Renvall and Niemela and A. infirma Renvall and Niemela (Basidiomycetes), are described. They have mostly been collected in Northern Finland. Both are associated with brown rot and they have been found almost exclusively on old windfalls of Pinus sylvestris. A. primaeva resembles Dichomitus squalens (Karst.) Reid in having resupine or effused-reflexed basidiocarps which are white to bay and soft when fresh. The overall structure of A. primaeva is trimitic; the tubes are dimitic, while the subculum and cap context consist predominantly of generative hyphae, but contain skeletals and scattered binding hyphae close to the tube bottoms and sometimes next to the wood. Dichomitus squalens differs in having aboriform and cyanophilous skeleto-binding hyphae. A. primaeva is microscopically close to A. serialis (Fr.) Donk, but skeletal hyphae are dominant in the content of the latter and its whole structure is tougher. A. infirma is dimitic with very rare skeletal hyphae. A. oleracea (Davidson and Lombard) Ryv. is similar to it, but has shorter basidiospores, shorter and almost pyriform basidia, smaller pores and different hosts. A. infirma is differentiated from Postia rancida (Bres.) Larsen and Lombard and P. placenta (Fr.) Larsen and Lombard by having true skeletals and longer, fusiform basidiospores. The vegetative hyphae of both the new species are unevenly distributed in the basidocarp. Skeletal hyphae are often found in clusters in the trama, and horizontal sectioning is a useful method for examining their occurrence and distribution. The authors consider that the significance of the structure of hyphal system as one of the basic characters in the taxonomy of polypores requires some re-evaluation. In addition, a new polypore species, Dichomitus stenospora Renvall and Niemala, is described on the basis of North America material.