Taxonomic and phylogenetic revision of three rare irpicoid species within the Meruliaceae

We have carried out a morphological and molecular study of Mycoacia nothofagi and Steccherinum lusitanicum, two rare irpicoid species collected in Spain. From Steccherinum lusitanicum, only the type of the species, collected in Portugal, was known to date. This has been compared with type material of Hydnum setulosum (a parts per thousand Hyphodontia setulosa) collected in the USA, confirming that both species are synonymous. We contribute with microphotographs of the most representative characters of the specimens. The molecular data based on ITS and partial 28S rRNA gene sequences show that both taxa should be accommodated within genus Phlebia. Our data suggest a close relationship between S. lusitanicum and the core of Phlebia sensu stricto (including the type species P. radiata), whereas M. nothofagi is apparently more closely related with another group of species that would include M. aurea, P. subserialis and P. livida, among others. The molecular phylogenetic analysis confirms that the genera Mycoacia and Mycoaciella, as well as Merulius, should be considered as synonyms of Phlebia.