Pluteus leoninus is a commonly reported species, characterized by a yellow pileus, yellow colors on the stipe, pleurocystidia provided with digitiform excrescences, and a pileipellis composed of long, fusiform elements. Several species related to P. leoninus have been described from the temperate and boreal areas of the Northern Hemisphere, and previous phylogenetic studies have shown that more than one species can be recognized around P. leoninus, but it was unclear how many, or which names, would be correct for them. We studied 141 holarctic collections in the /leoninus clade and available type collections of species in this group. Taking into account the morphological, molecular (ITS, tef1), ecological, and geographic variation in our data set, we recognize 12 holarctic species, six in Eurasia (P. favrei, P. leoninus, P. roseipes, P. ochraceoleoninus, sp. nov. P. ussuriensis, sp. nov. P. variabilicolor) and six in North America (P. aureus, sp. nov. P. croceus, sp. nov. P. flavofuligineus, P. hesperius, sp. nov. P. insularis, sp. nov. P. pumae, sp. nov.). Tropical species included by Singer in stirps Leoninus are briefly discussed: P. chrysaegis, originally described from Srik Lanka, is confirmed to occur in North America (Florida, Puerto Rico); we provide the first modern description and molecular data for P. conizatus, originally described from Sri Lanka, which is confirmed to be part of Pluteus sect. Hispidoderma but does not belong in the /leoninus clade.

Three novel species of the genus Leucocoprinus, named Lc. cinnamomeodiscus, Lc. dahranwalanus, and Lc. iqbalii, are described from unexplored regions of southern Punjab, Pakistan, based on comprehensive analyses of morphoanatomical characteristics and molecular phylogenetic data. We provide illustrations of freshly collected basidiomata and detailed line drawings highlighting key anatomical features. The molecular phylogenetic analyses, which are based on the internal transcribed spacer (ITS) region and combined ITS-28S sequences, consistently position these newly described species within the genus Leucocoprinus. Additionally, this study also introduces new taxonomic combinations for previously reported Leucoagaricus species.

Fungus-farming ants cultivate multiple lineages of fungi for food, but, because fungal cultivar relationships are largely unresolved, the history of fungus-ant coevolution remains poorly known. We designed probes targeting >2000 gene regions to generate a dated evolutionary tree for 475 fungi and combined it with a similarly generated tree for 276 ants. We found that fungus-ant agriculture originated similar to 66 million years ago when the end-of-Cretaceous asteroid impact temporarily interrupted photosynthesis, causing global mass extinctions but favoring the proliferation of fungi. Subsequently, similar to 27 million years ago, one ancestral fungal cultivar population became domesticated, i.e., obligately mutualistic, when seasonally dry habitats expanded in South America, likely isolating the cultivar population from its free-living, wet forest-dwelling conspecifics. By revealing these and other major transitions in fungus-ant coevolution, our results clarify the historical processes that shaped a model system for nonhuman agriculture.

Four new species of Albomagister, a genus of Tricholomataceae in the order Agaricales, are described and illustrated from eastern North America. All four are relatively rare or geographically restricted but two have a broad geographical distribution occurring in southeast Canada and in the southern Appalachians. This study increases the number of known species in the genus from three to seven, five of which occur in eastern North America. A broad concept for the genus is discussed. Illustrations and descriptions of the North American taxa are presented, along with a taxonomic key to the known seven species in the genus worldwide.

Cystolepiota Singer is rarely studied in Southeast Asia; here, we survey and describe three new species of Cystolepiota from tropical Laos and Thailand. Cystolepiota pyramidalis is related to C. fumosifolia (Murrill) Vellinga and C. pseudofumosifolia M.L. Xu & R.L. Zhao, but it is distinguished by pale to pastel yellow lamellae. Second, Cystolepiota thailandica differs from other members in the genus by the greyish-orange granulose or powdery pileus and stipe covering made up of globose to subglobose and sphaeropedunculate elements. Furthermore, Cystolepiota rhodella is characterized by the pink-violet granulose covering of the pileus and stipe and white lamellae with distinctly violet edges. Each species is provided with a full description of the morphological characters, photos in situ, line drawings of the microcharacters, discussion of related and similar species, and molecular data.

We are pleased to recommend "Common edible and poisonous mushrooms of southwestern China" by Yang, Wu, Li, Wang, and Cai. (2021).

Basidiomycota constitute a major phylum of the kingdom Fungi, distributed in 4 subphyla, 18 classes, 68 orders and 241 families. Advances in molecular phylogeny over the past years have resulted in numerous changes to their classification at a rapid pace. Consequently, a vast amount of taxonomic information is available in many publications. The website www.basidio.org/ is established with the aim of gathering and compiling these scattered data on a single platform. This website will provide an up-to-date outline of Basidiomycota, notes on orders, families and genera of Basidiomycota and updated accounts of each genus based on the most current literature, in a user-friendly way.

In our ongoing research on lepiotaceous taxa (Agaricaceae s.l.) in Laos and northern Thailand, we focus here on Chlorophyllum, Clarkeinda, Macrolepiota, Pseudolepiota, and Xanthagaricus. Collections were obtained from various habitats, including agricultural habitats, grasslands, and rainforests. A total of 12 taxa were examined and investigated. Of these 12, two are new for science; viz. Xanthagaricus purpureosquamulosus with brownish-grey to violet-brown squamules on a pale-violet to violet background; it shares the pileus color with X. caeruleus and X. ianthinus, but differs in other characters; and Macrolepiota excelsa, rather similar to M. procera but related to M. detersa. Two species, Pseudolepiotazangmui and Xanthagaricus necopinatus are recorded for the first time in Thailand. Four species of Chlorophyllum and a total of four species of Macrolepiota were found, viz., C. demangei and C. hortense with white basidiospores, C. molybdites and C. globosum with green basidiospores, M. detersa, M. dolichaula, the new M. excelsa, and M. velosa. Another rather common striking species is Clarkeinda trachodes, with yellow-green basidiospores. Each species is described in detail, with color photographs and line drawings. Phylogenetic analyses based on internal transcribed spacer (nrITS) region, the large subunit nuclear ribosomal (nrLSU) DNA and RNA polymerase II second largest subunit (rpb2) genes provide evidence for the placement of the species covered.

(2749) Chlorophyllum Massee in Bull. Misc. Inform. Kew 1898: 135. Jun 1898, nom. cons. Typus: C. esculentum Massee [= C. molybdites (G. Mey.) Massee ex P. Syd. (Agaricus molybdites G. Mey.)]. (=) Secotium Kunze in Flora 23: 321. 7 Jun 1840, nom. rej. prop. Typus: S. gueinzii Kunze Secotium Kunze (in Flora 23: 321–322. 1840) is a genus comprising about 60 described species whose taxonomic position has long been controversial (De Toni in Saccardo, Syll. Fung. 7: 51–55. 1888; Conard in Mycologia 7: 94–104. 1915; Cunningham in Proc. Linn. Soc. New South Wales 49: 97–119. 1924; Heim in Rev. Mycol. (Paris) 16: 129–153. 1951; Singer & Smith in Madroño 15: 152–158. 1960). The genus was erected to accommodate species with spore maturation within enclosed basidiomata and a stipe extending as a columella into the spore-bearing part, a morphology since termed "secotioid" (Thiers in Mycologia 76: 1–8. 1984). The latter term is now commonly applied to intermediates between gasteroid and agaricoid phenotypes (Hibbett & al. in Amer. J. Bot. 81: 466–478. 1994; Albee-Scott in Mycol. Res. 111: 1030–1039. 2007), which have evolved convergently in many genera of Agaricales Underw., including Agaricus L., Amanita Pers., Cortinarius (Pers.) Gray, and Chlorophyllum Massee (e.g., Peintner & al. in Amer. J. Bot. 88: 2168–2179. 2001; Vellinga & al. in Mycologia 95: 442–456. 2003; Geml in Acta Microbiol. Immunol. Hung. 51: 97–108. 2004; Gube, Ontogeny Phylogeny Gasteroid Agaricaceae, Doctoral Diss., Friedrich-Schiller-Universität, Jena. 2009; Justo & al. in Mycologia 102: 675–688. 2010; Lebel & Syme in Mycologia 104: 496–520. 2012; Vidal & al. in Persoonia 42: 127–185. 2019). Secotium gueinzii Kunze, the original type of Secotium, was not separately described (Kunze, l.c.) but was later discussed in greater depth by Berkeley (in London J. Bot. 2: 507–527. 1843), Bottomley (in Bothalia 4: 474–810. 1948), and Singer & Smith (l.c.). However, genetic data from this species was lacking until recently; therefore its phylogenetic identity, as well as the status of the genus remained nebulous. The successful sequencing of the ITS locus of a 1963 collection made by E.L. Stephens (MICH 4378, designated as epitype) (Loizides & al. in Mycologia 112: 400–422. 2020), confirmed that S. gueinzii in fact nests within Chlorophyllum sect. Chlorophyllum and is sister to the agaricoid species C. globosum. The majority of Secotium species have been transferred to other genera in the Agaricales, Boletales E.-J. Gilbert, and Russulales Kreisel ex P.M. Kirk & al. These include species such as Secotium areolatum G. Cunn. (now Boletus semigastroideus Nuhn & al.), S. agaricoides (Czern.) Hollós (now Chlorophyllum agaricoides (Czern.) Vellinga), S. krjukowensis Bucholtz (now Russula krjukowensis (Bucholtz) Trappe & T.F. Elliott), S. nova-zelandiae G. Cunn. (now Psilocybe weraroa Borovička & al.), S. olbium Tul. & C. Tul. (now Lepiota olbia (Tul. & C. Tul.) J.M. Vidal & P.-A. Moreau), and S. porphyreum G. Cunn. (now Cortinarius porphyroideus Peintner & M.M. Moser) (Peintner & al., l.c.; Vellinga & al., l.c.; Borovička & al. in Mycol. Progr. 10: 149–155. 2011; Elliott & Trappe in Fungal Syst. Evol. 1: 229–242. 2018; Vidal & al. in Bol. Micol. FAMCAL 10: 47–71. 2019). In addition, several species of Secotium have been synonymized with other earlier taxa (e.g., Cunningham [l.c.] included Secotium acuminatum Mont., S. pedunculatum Lloyd, S. szabolcsense Haszl., S. thunii Schulzer, and S. warnei (Peck) Peck under S. agaricoides [now Chlorophyllum agaricoides]). At the moment, only about 15 very rare or poorly known species remain classified within Secotium, many of which may be unrelated to the type, S. gueinzii, given their deviating macro- and micromorphological characters. For example, S. coprinoides Routien is a 4 mm tall species with coprinoid spores, known only from the type collection (Routien in Mycologia 32: 159–169. 1940). Chlorophyllum Massee (in Bull. Misc. Inform. Kew. 1898: 135. 1898) currently accommodates 27 described species, 18 of which are phylogenetically confirmed (Ge & al. in MycoKeys 32: 65–90. 2018; Loizides & al., l.c.). Although the genus was originally erected to accommodate green-spored agaricoid species (typified by Chlorophyllum esculentum Massee, now referred to C. molybdites), phylogenetic studies revealed that it is morphologically diverse, after several pale-spored species formerly placed in Macrolepiota Singer and Leucoagaricus Locq. ex Singer were shown to nest in Chlorophyllum (Vellinga in Mycotaxon 83: 415–417. 2002; Vellinga in Austral. Syst. Bot. 16: 361–370. 2003; Vellinga & al., l.c.). In addition, the secotioid genus Endoptychum Czern. (in Bull. Soc. Imp. Naturalistes Moscou 18(2): 132–157. 1845) was synonymized with Chlorophyllum after phylogenetic studies revealed that the type, E. agaricoides Czern., also nests within the Chlorophyllum clade (Vellinga, l.c. 2002; Vellinga & al., l.c.). In the latter case, the generic name Chlorophyllum was conserved against the generic name Endoptychum, which has chronological priority over the former (Vellinga & De Kok in Taxon 51: 563–564. 2002). Since then, three other secotioid species have been added to Chlorophyllum: C. arizonicum (Shear & Griffiths) G. Moreno & Altés, a species formerly classified in Secotium and later placed in Endoptychum (Singer & Smith in Brittonia 10: 216–221. 1958), and two new closely related species, C. lusitanicum G. Moreno & al. and C. levantinum Loizides & al. (Crous & al. in Persoonia 35: 264–327. 2015; Loizides & al., l.c.). Thus, the Chlorophyllum clade currently contains five secotioid taxa (C. agaricoides, C. arizonicum, S. gueinzii, C. levantinum, C. lusitanicum) among a majority of large, agaricoid species with variable spore shapes and spore colours. The phylogenetic placement of Secotium gueinzii in Chlorophyllum gives rise to a nomenclatural problem, since the generic name Secotium (1840) has priority over Chlorophyllum (1898). Therefore, unless the generic name Chlorophyllum is conserved against Secotium, all agaricoid taxa currently placed in Chlorophyllum would have to be re-combined into the secotioid genus Secotium. We consider the latter option undesirable and propose to formally conserve Chlorophyllum against Secotium for the following reasons: (1) Chlorophyllum is now, 18 years after re-combination of the first secotioid taxon into the genus, widely known to accommodate both agaricoid and secotioid species; (2) the term "secotioid" derives from the genus name Secotium, thus combinations of agaricoid taxa within Secotium would be confusing; (3) confusion would be avoided regarding the well-established usage of the term "secotioid" itself, which would then refer only to a historical definition of the genus Secotium and not so obviously relate to secotioid phenotypes in general terms; (4) Chlorophyllum includes the common poisonous species C. molybdites (of which the generic type is a taxonomic synonym), a name well-known among physicians and toxicologists, and confusion over its nomenclature might lead to dangerous delays in treatment of poisonings; (5) the status of the majority of taxa in Secotium remains unresolved and many of them are likely to be unrelated to the type, S. gueinzii, and to each other, or to be synonymous with already recombined species (e.g., Chlorophyllum agaricoides); (6) conversely, the majority of taxa in Chlorophyllum are genetically resolved and tightly linked to the corresponding DNA sequences; (7) if the proposal is accepted, nomenclatural disruption would be minimal because fewer name changes would be required, with a maximum of 15 species to be renamed, as opposed to 27 name changes in the case of rejection of this proposal; (8) for similar reasons, Chlorophyllum has already been conserved against Endoptychum. MG, https://orcid.org/0000-0001-5101-3096 ECV, https://orcid.org/0000-0003-4171-0554 GIZ, https://orcid.org/0000-0002-2892-098X

During our studies of the genus Lepiota in northern Thailand we collected a putatively new species with a distinct morphology and ITS nrDNA profile from Chiang Mai Province. The new species, Lepiota condylospora, is characterized by the presence of reddish brown to brownish orange or brown squamules on the pileus surface, triangular basidiospores with two lateral knobs, and a hymenidermal pileipellis composed of broadly to narrowly clavate elements. Two genetically distinct species of Lepiota section Lilaceae having triangular spores with two lateral knobs are compared with L. condylospora: Lepiota fraterna, from Papua New Guinea, differs in having larger basidiospores and cheilocystidia; while L. cristata var. macrospora, from China, has bigger basidiomata. A full description, color photographs, line drawings and a phylogenetic tree to show the position of the new species are provided.

Understanding diversity in the genus Xerocomellus in western North America has been obscured by morphological variability, widespread use of species epithets typified by specimens from Europe and eastern North America, misunderstood phylogenetic relationships, and species complexes. We collected extensively and used genetic and morphological data to establish the occurrence of ten Xerocomellus species in western North America. We generated ITS sequences from five type collections and from vouchered representative collections to clarify our understanding of existing species concepts. We describe three new species (Xerocomellus atropurpureus, X. diffractus, and X. salicicola) and propose two new combinations (X. amylosporus and X. mendocinensis), transfer Boletus coccyginus to Hortiboletus, and provide a dichotomous key to species of Xerocomellus in western North America.

The Basidiomycota constitutes a major phylum of the kingdom Fungi and is second in species numbers to the Ascomycota. The present work provides an overview of all validly published, currently used basidiomycete genera to date in a single document. An outline of all genera of Basidiomycota is provided, which includes 1928 currently used genera names, with 1263 synonyms, which are distributed in 241 families, 68 orders, 18 classes and four subphyla. We provide brief notes for each accepted genus including information on classification, number of accepted species, type species, life mode, habitat, distribution, and sequence information. Furthermore, three phylogenetic analyses with combined LSU, SSU, 5.8s, rpb1, rpb2, and ef1 datasets for the subphyla Agaricomycotina, Pucciniomycotina and Ustilaginomycotina are conducted, respectively. Divergence time estimates are provided to the family level with 632 species from 62 orders, 168 families and 605 genera. Our study indicates that the divergence times of the subphyla in Basidiomycota are 406–430 Mya, classes are 211–383 Mya, and orders are 99–323 Mya, which are largely consistent with previous studies. In this study, all phylogenetically supported families were dated, with the families of Agaricomycotina diverging from 27–178 Mya, Pucciniomycotina from 85–222 Mya, and Ustilaginomycotina from 79–177 Mya. Divergence times as additional criterion in ranking provide additional evidence to resolve taxonomic problems in the Basidiomycota taxonomic system, and also provide a better understanding of their phylogeny and evolution.

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.

Nomenclatural type definitions are one of the most important concepts in biological nomenclature. Being physical objects that can be re-studied by other researchers, types permanently link taxonomy (an artificial agreement to classify biological diversity) with nomenclature (an artificial agreement to name biological diversity). Two proposals to amend the International Code of Nomenclature for algae, fungi, and plants (ICN), allowing DNA sequences alone (of any region and extent) to serve as types of taxon names for voucherless fungi (mainly putative taxa from environmental DNA sequences), have been submitted to be voted on at the 11th International Mycological Congress (Puerto Rico, July 2018). We consider various genetic processes affecting the distribution of alleles among taxa and find that alleles may not consistently and uniquely represent the species within which they are contained. Should the proposals be accepted, the meaning of nomenclatural types would change in a fundamental way from physical objects as sources of data to the data themselves. Such changes are conducive to irreproducible science, the potential typification on artefactual data, and massive creation of names with low information content, ultimately causing nomenclatural instability and unnecessary work for future researchers that would stall future explorations of fungal diversity. We conclude that the acceptance of DNA sequences alone as types of names of taxa, under the terms used in the current proposals, is unnecessary and would not solve the problem of naming putative taxa known only from DNA sequences in a scientifically defensible way. As an alternative, we highlight the use of formulas for naming putative taxa (candidate taxa) that do not require any modification of the ICN.

The corticioid fungi are commonly encountered, highly diverse, ecologically important, and understudied. We collected specimens in 60 pine and spruce forests across North America to survey corticioid fungal frequency and distribution and to compile an internal transcribed spacer (ITS) database for the group. Sanger sequences from the ITS region of vouchered specimens were compared with sequences on GenBank and UNITE, and with high-throughput sequence data from soil and roots taken at the same sites. Out of 425 high-quality Sanger sequences from vouchered specimens, we recovered 223 distinct operational taxonomic units (OTUs), the majority of which could not be assigned to species by matching to the BLAST database. Corticioid fungi were found to be hyperdiverse, as supported by the observations that nearly two-thirds of our OTUs were represented by single collections and species estimator curves showed steep slopes with no plateaus. We estimate that 14.8-24.7% of our voucher-based OTUs are likely to be ectomycorrhizal (EM). Corticioid fungi recovered from the soil formed a different community assemblage, with EM taxa accounting for 40.5-58.6% of OTUs. We compared basidioma sequences with EM root tips from our data, GenBank, or UNITE, and with this approach, we reiterate existing speculations that Trechispora stellulata is EM. We found that corticioid fungi have a significant distance-decay pattern, adding to the literature supporting fungi as having geographically structured communities. This study provides a first view of the diversity of this important group across North American pine forests, but much of the biology and taxonomy of these diverse, important, and widespread fungi remains unknown.

Recently the well-known genus Amanita has been split into two genera, Amanita, a genus of putatively ectomycorrhizal fungi, and Saproamanita, a genus of putatively saprotrophic fungi. We disagree with this generic split and argue why Amanita should not be split. The proposal to split the genus does not conform to the recently proposed guidelines for publishing new genera. Concise amended characterizations are provided for the monophyletic family Amanitaceae and its two monophyletic genera Amanita and Limacella.2 The characterization of Amanita rests on a single, unique synapomorphy—schizohymenial ontogeny in its agaricoid and secotioid taxa. We propose a minimal reorganization of Amanita—removal of stirps Hesleri from subsection Vittadiniae. Some open issues in Amanita systematics are discussed. Amanita is an emblematic genus and the focus of diverse research programs. Taxonomists and users of taxonomic and systematic products are used to, and rely on, Amanita as a genus with meaningful, morphologically defined subdivisions, easy to teach and easy to use. Splitting the genus is unnecessary and would prove costly—degrading our ability to communicate with each other and complicating connections to past literature. We argue that the current use of next-generation sequencing in studies of fungal ecology does not necessitate the splitting of Amanita.