The tropics were long considered to have few ectomycorrhizal fungi, presumably due to a paucity of ectomycorrhizal host plants relative to higher-latitude ecosystems. However, an increase in research in tropical regions over the past 30 years has greatly expanded knowledge about the occurrence of tropical ectomycorrhizal fungi. To assess their broad biogeographic and diversity patterns, we conducted a comprehensive review and quantitative data analysis of 49 studies with 80 individual data sets along with additional data from GlobalFungi to elucidate tropical diversity patterns and biogeography of ectomycorrhizal fungi across the four main tropical regions: the Afrotropics, the Neotropics, Southeast Asia, and Oceania. Generalized linear models were used to explore biotic and abiotic influences on the relative abundance of the 10 most frequently occurring lineages. We also reviewed the available literature and synthesized current knowledge about responses of fungi to anthropogenic disturbances, and their conservation status and threats. We found that /russula-lactarius and /tomentella-thelephora were the most abundant lineages in the Afrotropics, the Neotropics, and Southeast Asia, whereas /cortinarius was the most abundant lineage in Oceania, and that /russula-lactarius, /inocybe, and /tomentella-thelephora were the most species-rich lineages across all of the tropical regions. Based on these analyses, we highlight knowledge gaps for each tropical region. Increased sampling of tropical regions, collaborative efforts, and use of molecular methodologies are needed for a more comprehensive view of the ecology and diversity of tropical ectomycorrhizal fungi.

Three species of Lepiota sensu lato from China are described and illustrated based on morphological characters and molecular evidence. Echinoderma flavidoasperum and Lepiota omninoflava are new to science, while Lepiota echinacea is newly reported from China. Echinoderma flavidoasperum is characterized by a yellow pileus, nearly smooth stipe that discolors light red when bruised, and subcylindrical basidiospores. Lepiota omninoflava, so far only found in the tropics, is characterized by the yellow basidiomata, ellipsoid basidiospores and the absence of cheilocystidia. All three of the Chinese species are discussed and placed within a phylogeny based on the internal transcribed spacer (ITS) region, the large subunit (LSU) of the ribosomal DNA, the translation elongation factor 1-α (tef1-α) and the second largest subunit of RNA polymerase II (rpb2).

Taxonomic and phylogenetic studies of Chlorophyllum were carried out on the basis of morphological differences and molecular phylogenetic analyses. Based on the phylogeny inferred from the internal transcribed spacer (ITS), the partial large subunit nuclear ribosomal DNA (nrLSU), the second largest subunit of RNA polymerase II (rpb2) and translation elongation factor 1-α (tef1) sequences, six well-supported clades and 17 phylogenetic species are recognised. Within this phylogenetic framework and considering the diagnostic morphological characters, two new species, C.africanum and C.palaeotropicum, are described. In addition, a new infrageneric classification of Chlorophyllum is proposed, in which the genus is divided into six sections. One new combination is also made. This study provides a robust basis for a more detailed investigation of diversity and biogeography of Chlorophyllum.

The burgeoning accumulation of genomic data in recent years has revolutionized our understanding of fungal phylogenies and classifications. However, the genomic era also brings new challenges, as phylogenetic incongruences make the appearance of monophyly in some phylogenetic trees questionable. Existing criteria for constructing taxonomic systems, such as diagnostic characters and divergence time, become insufficient to address this challenge. Through order-level analyses of genomic data of the Subkingdom Dikarya within the Kingdom Fungi, we introduce the extended quadripartition internode certainty (EQP-IC) value as a novel criterion for constructing high-level fungal classifications, with a recommended threshold of 0.1 for each taxonomic rank. Suprageneric taxa with an EQP-IC value exceeding 0.1 exhibit reduced topological variation, suggesting a stronger correspondence with natural taxonomic category. This new criterion was also put into practice to investigate the derived suborders of mushroom-forming Agaricales, including three suborders, Agaricineae, Pluteineae, and Tricholomatineae (APT), that had been long-standing problems in phylogenetic analyses. In total, 142 genomes, including 64 newly generated ones, were utilized to reconstruct the phylogenetic relationships and delve into the phylogenetic incongruencies and evolutionary histories of APT. Our data suggested widespread and high-level incomplete lineage sorting (ILS) and introgression/hybridization (IH) present among suborders within the APT. Therefore, a dichotomous phylogenetic tree may not reflect the real relationships among the clades within the APT. Instead, their natural relationships may be reticulate. Three newly named suborders, Amanitineae, Macrocystidiineae, and Omphalinineae are added to the clade including APT. The new combination Baisuzhenia humphreyi, new genus Baisuzhenia, new family Baisuzheniaceae, and new suborder Baisuzheniineae are proposed to accommodate Stereopsis humphreyi, which shows an independent, but close relationship, with the clade formed by the six above-mentioned derived suborders of Agaricales.