Species recognition and phylogenetic relationships of European Porodaedalea (Basidiomycota, Hymenochaetales)

The genus Porodaedalea is a taxonomically difficult complex of morphologically similar species that inhabit conifers. The evolutionary relationships of European species were examined using sequences of the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA and of translation elongation factor 1 alpha (tefa). Our results confirm the occurrence of Porodaedalea chrysoloma, P. pini and P. laricis in Europe. P. laricis is newly reported in Fennoscandia on Picea and in the Central European mountains (Alps, High Tatras, and Bohemian forest) on Larix and Pinus spp. These specimens had been previously identified as Porodaedalea chrysoloma or Phellinus vorax (an invalidly described species). Although frequently confused, P. chrysoloma and P. laricis can be distinguished on the basis of pore morphology. We also report our finding of P. pini on Larix. In general, the tefa sequences are more variable than the ITS sequences and reveal the remarkable affinity of some Scandinavian and Central European specimens of P. laricis to those from Central Asia. Furthermore, we discovered evidence of interspecific hybridisation between P. pini and P. laricis. In addition, our study revealed the presence of an undescribed species in Morocco. Our results are compared with the results of compatibility tests in this genus that have been published previously.