A phylogeny of the <i>Inocybe alienospora</i> group (Agaricales) with emphasis on seven new species from China and emendation of sect. <i>Leptocybe</i>

A multigene phylogeny of the <i>Inocybe alienospora</i> group is presented based on analyses of ITS, 28S, and <i>rpb2</i> nucleotide data. Four major subclades and three additional independent lineages were identified in the <i>I. alienospora</i> group. Two species with superficial similarities with the <i>I. alienospora</i> group, viz, <i>I. multicoronata</i> and <i>I. elata</i>, however, were not nested within the <i>I. alienospora</i> group. <i>Inocybe</i> sect. <i>Leptocybe</i> is proposed to accommodate the <i>I. alienospora</i> group in a more formal classification system. As such, sect. <i>Leptocybe</i> now includes 12 documented species and seven new species described in this work. The seven new species include <i>I. aprica</i> sp. nov., <i>I. casuarinoides</i> sp. nov. <i>I. haikouensis</i> sp. nov., three species associated with <i>Casuarina</i> from tropical China; also <i>I. heteromorpha</i>, a species associated with fagaceous trees from tropical China; and <i>I. aurescens</i> sp. nov., <i>I. juji</i> sp. nov., and <i>I. peppa</i> sp. nov., three species associated with fagaceous trees from subtropical China. In addition, new geographical data for <i>I. carpinicola</i> and <i>I. acutata</i> are reported. The East Asian species <i>I. acutata</i> and the neotropical species <i>I. lasseri</i> were confirmed as members of sect. <i>Leptocybe</i>. A key to the 19 species in sect. <i>Leptocybe</i> is also provided.