Molecular phylogeny of species in the generaAmylostereum andEchinodontium

Analyses of DNA sequences from the internal transcribed spacer (ITS) region of the nuclear rDNA and from a portion of a manganese-dependent peroxidase gene were used to assess the species inAmylostereum, including isolates from the mycangia of horntails, decay, and basidiomes. Four species are recognized:A. areolatum, A. chailletii, A. laevigatum, andA. ferreum. An unidentifiedAmylosterum isolate from the mycangium ofXoanon matsumurae had an ITS sequence identical to that ofA. areolatum. Another unidentifiedAmylostereum isolate from the mycangium ofSirex areolatus was nearA. laevigatum, which appears to be the mycangial symbiont for those horntails attacking cedar-like trees. The other horntail isolates, primarily from Pinaceae, proved to be eitherA. areolatum orA. chailletii. The DNA sequences ofEchinodontium tinctorium, E. tsugicola andE. japonicum were similar to those of theAmylostereum species, andAmylostereum species are now recognized as members of the family Echinodontiaceae rather than the family Stereaceae.Echinodontium taxodii was found to be distinct from the Echinodontiacaea andStereum, andE. taxodii is recognized as aLaurilia species.