Molecular phylogeny of species in the genera Amylostereum and

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 in Amylostereum, including isolates from the mycangia of horntails, decay, and basidiomes. Four species are recognized: A. areolatum, A. chailletii, A. laevigatum, and A. ferreum. An unidentified Amylostereum isolate from the mycangium of Xoanon matsumurae had an ITS sequence identical to that of A. areolatum. Another unidentified Amylostereum isolate from the mycangium of Sirex areolatus was near A. 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 either A. areolatum or A. chailletii. The DNA sequences of Echinodontium tinctorium, E. tsugicola and E. japonicum were similar to those of the Amylostereum species, and Amylostereum species are now recognized as members of the family Echinodontiaceae rather than the family Stereaceae. Echinodontium taxodii was found to be distinct from the Echinodontiaceae and Stereum, and E. taxodii is recognized as a Laurilia species.