Two New Species of Lactifluus (Basidiomycota, Russulales) Sections Piperati and Albati Inhabiting Tropical Quercus Forests of Eastern Mexico

Mexican species of <i>Lactifluus</i> have often been identified using names of morphologically similar Old World taxa. However, integrative approaches combining morphological and molecular data have revealed a high level of previously unrecognized diversity in the region. Here, two new species from lowland tropical <i>Quercus</i> forest are described: one in section <i>Piperati</i> (subgenus <i>Lactifluus</i>), characterized by pale yellow basidiomes and another in section <i>Albati</i> (subgenus <i>Lactariopsis</i>), with whitish basidiomes. The two taxa are distinguished by a unique set of macro- and micromorphological features, and their recognition is strongly supported by phylogenetic evidence from a concatenated dataset including nc ITS rDNA, nc 28S rDNA and the 6-7 region of the second largest subunit of the RNA polymerase II (<i>rpb2</i>).