Pseudobaeosporoideae, a new subfamily within the Tricholomataceae for the genus Pseudobaeospora (Agaricales, Tricholomatineae) based on morphological and molecular inference

Based on molecular and morphological evidence the new subfamily <i>Pseudobaeosporoideae</i> of the <i>Tricholomataceae</i> is established within the <i>Tricholomatineae</i> for accommodating the unique features of <i>Pseudobaeospora</i> such as gymnocarpic mycenoid/collybioid habit, small-sized spores with thick and dextrinoid wall, and presence of crassobasidia. Twenty-six <i>Pseudobaeospora</i> collections corresponding to eleven species (five types) were newly sequenced. Collections morphologically attributable to <i>P.oligophylla</i> (type of the genus) or to <i>P.pillodii</i> are here sequenced for the first time: accordingly, <i>P.oligophylla</i> is considered as a posterior synonym of <i>P.pillodii</i>. Quélet's original plate is selected as a lectotype for <i>Collybiapillodii</i> and a French collection as its epitype collection. <i>Pseudobaeosporadeceptiva</i> is described as a new species from Italy very close to <i>P.pillodii</i> from which it differs mainly by bigger spores and SSU and LSU rDNA sequences. The presence of <i>P.pyrifera</i> in Italy is documented for the first time and <i>P.mutabilis</i> is reduced to its later synonym. A neotype is established for <i>P.jamonii</i> which is here proved to be an independent species. Finally, a critical review of the characters used for interspecific distinctions in <i>Pseudobaeospora</i> was provided.