An agaric belonging to the Leucoagaricus-Leucocoprinus group (AC group) of Agaricaceae s. l., commonly found in South China, was usually identified as Leucoagaricus lacrymans or Lepiota shixingensis in previous researches. However, as this agaric is also close to La. sinicus and the phylogeny of the AC group has not been resolved, its taxonomic position has not been elucidated. In this study, by reconstructing the phylogeny of the AC group and its closely related genera based on four DNA loci (ITS, nrLSU, rpb2, and tef-1α), the AC group is resolved as polyphyletic but formed a monophyletic group together with Micropsalliota, and is divided into four genera: Leucoagaricus, Leucocoprinus, and two newly described genera close to Micropsalliota, namely Candelolepiota and Macropsalliota. Candelolepiota is a monotypic genus that accommodates this agaric as Candelolepiota sinicus (≡ Leucoagaricus sinicus), characterized by basidiomata excreting colored droplets when fresh, turning brownish after touched or damaged, and subcylindrical, flexuous cheilocystidia. Leucoagaricus lacrymans is a later synonym of Cd. sinicus. Macropsalliota is similar to Micropsalliota, but differs from the latter by usually more robust basidiomata, pileus with granular, fibrous or flaky squamules composed of perpendicular to interwoven hyphae, whitish to yellowish lamellae and slightly colored basidiospores with a germ pore, accommodating the previously recognized La. americanus and its related species. Leucoagaricus is revised to accommodate species that are usually saprotrophic in forests, not symbiotic with attine ant species, producing slender to moderately robust basidiomata without a distinct color change after touched, damaged, or dried, with a non-plicate to shortly plicate pileus without or with squamules composed of horizontal to interwoven hyphae, and basidiospores without a germ pore. Leucocoprinus is revised to accommodate species that are widely saprotrophic in forests, lawns, urban areas, and compost, occasionally symbiotic with attine ant species, producing slender to robust basidiomata turning reddish, purplish, greenish to bluish or without a distinct color change after touched, damaged, or dried, with a non-plicate to plicate pileus with squamules composed of perpendicular to interwoven hyphae, and basidiospores with or without a germ pore. The presence or absence of a long continuous gap region in the ITS alignment is also found to be informative for the recognition of Micropsalliota, Macropsalliota, and the other three genera in the AC group. Fifty-three new combinations are proposed. The genus Lepiota is recognized as separated from Agaricaceae s. str. and belonging to the family Lepiotaceae.

A cup fungus producing ascomata on senescing to dead rhizomes of bamboo in East China is described as Pseudoplectania mystica sp. nov. (Ascomycota, Pezizales) based on morphological, ecological and phylogenetic evidence. Some sequences of unidentified endophytic fungi uploaded to the GenBank database by other researchers were also identified as P. mystica in our phylogeny. By checking the original literature of these sequences, P. mystica was further found to act as an endophyte in a broad range of host plants including Aegiceras, Cinnamomum, Dendrobium and Lindera, probably lurking in the tissues of the host plants as invisible mycelium in most cases and only producing visible ascomata following senescence of the host tissues. Such ecology and a combination of all its morphological characteristics make P. mystica recognizable from other known species of Pseudoplectania. This study contributes to the understanding of the species diversity and lifecycle of Pseudoplectania.

During an investigation on psathyrelloid fungi conducted from 2023 to 2024 in the Pearl River Delta in South China, 49 collections were gathered and studied through morphological observations and phylogenetic analyses. Among these collections, eight are identified as a new species of a new genus, namely Cantonopsathyra serendipita, characterized by terrestrial psathyrelloid basidiomata with a slightly rugose pileus, basidiospores with an irregularly wrinkled surface, and the rare presence of pleurocystidia and clamp connections; two are identified as a new species of Parasola, namely Pa. haizhuensis, characterized by lignicolous psathyrelloid basidiomata with an undulate pileus margin; while the remaining 39 could only be identified to the generic level of Candolleomyces. Species delimitation within Candolleomyces is found to be challenging, because the following problems often occur in the hypothetical species on our ITS phylogeny: (1) with an ITS sequence more than 99% similar to that of another species; (2) issued by a very short branch from the backbone; (3) unsupported by statistical values; (4) not a monophyletic group; and (5) with inaccurate sequences. A four-locus (ITS, nrLSU, tef-1α, and β-tub) phylogenetic analysis with limited samples of Candolleomyces appears to alleviate most of these problems by providing clearer partitions; however, four-locus data for previously proposed species remain largely unavailable for comparison. Based on the recent scale of species delimitation in Candolleomyces, more than ten new species of Candolleomyces appear to exist in our collections; however, due to the aforementioned issues, they are not formally proposed in this study. We recommend that new species of Candolleomyces proposed in the future should be provided with four-locus data of ITS, nrLSU, tef-1α, and β-tub. Supplementary sequencing for unprovided loci from type materials of previously proposed Candolleomyces species, particularly those proposed in recent years, is also highly encouraged. The recently proposed genus Tulosesus is illegitimate due to its circumscription including the type of an earlier legitimate genus, Ephemerocybe, and corresponding new combinations for transfer are made. Another genus, Lacrymaria Pat. 1887, is also illegitimate due to the homonymy with an earlier protist genus, Lacrymaria Ehrenberg 1830, but may be worth conserving; therefore, it is not treated here.

The taxonomy regarding three closely related genera of Agaricaceae, viz. Heinemannomyces, Hymenagaricus and Xanthagaricus, is updated based on morphological and four-locus molecular phylogenetic evidence from collections gathered in South China. Thirteen species identified from 122 collections are described, including Heinemannomyces splendidissimus, eight new species of Xanthagaricus, viz. X. boluoshanensis, X. chamaeleontinus, X. guangzhouensis, X. heinemannii, X. minimus, X. phylononcaeruleus, X. retisporus and X. scauinus, and four known species of Xanthagaricus, viz. X. erinaceus, X. ianthinus, X. necopinatus and X. purpureosquamulosus. Among them, He. splendidissimus is phylogenetically recognized as a Hymenagaricus species, namely Hy. splendidissimus, and Xanthagaricus heinemannii is morphologically similar to Hy. splendidissimus in floccose squamules on the pileus and stipe. Both species have pileus squamules composed of inflated cells in the lower layer and hyphae forming an irregular trichoderm in the upper layer. However, X. heinemannii differs from Hy. splendidissimus by the context not turning reddish after damaged, brownish lamellae, and usually without hymeniform elements in pileus squamules. These findings suggest that species of both Hymenagaricus and Xanthagaricus may present hyphae forming an irregular trichoderm in pileus squamules. Xanthagaricus erinaceus is rediscovered after 40 years, together with X. necopinatus and X. purpureosquamulosus are three newly recorded species in China.

Marine fungi have been studied for a long history in many realms, but there are few reports on marine mushrooms. In this study, marine fungi with conspicuous subglobose sequestrate basidioma were discovered from mangrove forests in South China. They grow on the deadwood of mangroves in the intertidal zone, periodically submerging into seawater due to the tide. Some marine animals were observed to nest in their basidiomata or consume them as food. The pileus-gleba-inner veil complex (PGI) of the basidioma was observed to be detached from the stipe and transferred into seawater by external forces, and drifting on sea to spread spores after maturity. The detachment mechanism of their PGIs was revealed through detailed microscopic observations. The contrast culturing experiment using freshwater and seawater potato dextrose agar media showed they have probably obligately adapted to the marine environment. Based on morphological and molecular phylogenetic evidence, two new species of Candolleomyces (Basidiomycota, Agaricales), namely C. brunneovagabundus and C. albovagabundus, were described. They are similar and close to each other, but can be distinguished by the size and color of the basidioma, and the size of the basidiospores.

Concerns about potential negative impacts of human activity on macrofungal diversity are spreading globally, yet research on this topic remains scarce. This study focuses on forest grazing (silvopasture), a popular economic practice whose impacts on macrofungal diversity are underexplored. Through investigation and comparison of macrofungal diversity and selected environmental factors in three types of subtropical forests (secondary mixed forests, dense-tree plantations and sparse-tree plantations) before and after two years of grazing at an intensity of 10 goats per hectare in South China, three key findings emerged: (1) Macrofungal alpha-diversity increased significantly after grazing, associated with an increase in large plant remains and a decrease in litterfall thickness; (2) dominance was monopolized by few taxa before grazing but became more balanced among a number of taxa after grazing; and (3) dominance of endemic taxa decreased in two of the three types of forests after grazing. Such findings suggest that grazing may create additional niches through foraging, trampling and excretion by livestock and thus recruit diverse macrofungi but may also lead to homogenization of fungal florae across regions and thus result in recessive beta-diversity loss. As this study heavily relies on taxonomy, allied updates for ambiguous taxa recognized in analyses are additionally proposed.