Novelties in Lactifluus subg. Gymnocarpi (Russulales, Basidiomycota) from Brazilian tropical forests

Lactifluus is an ectomycorrhizal genus that occurs predominantly in the tropical and subtropical regions. In Brazil, knowledge of species diversity in Lactifluus is restricted to the Amazon, Atlantic Forest, and Caatinga biomes, where several species have been described in subgenera Lactariopsis and Pseudogymnocarpi . Until now, subg. Gymnocarpi was represented in Brazil only by Lf. panuoides . Based on morphological and phylogenetic analyses, three novel species of Lf. subg. Gymnocarpi are described from Brazilian tropical forests: Lf. guttulatus , Lf. piperogalactus , and Lf. spathuliformis . Lactifluus lepus , originally described in the Caribbean, has been found in a dense ombrophilous forest of Amazon and is also described, illustrated, and discussed. A combined dataset of nuclear rDNA internal transcribed spacer region (ITS) and RNA polymerase II second largest subunit ( RPB2 ) was analyzed. Based on phylogenetic and morphological data, the agaricoid sect. Piperogalacti is erected and the pleurotoid sect. Panuoidei is emended.