Tom W. May

There is an exponential increase in the number of fungal OTUs being documented by environmental DNA (eDNA) metabarcoding. Many of these, the so-called dark fungal taxa (DFT), are known only from eDNA data, with no associated physical specimen or derived culture. Of the millions of fungal species predicted to exist, only ~205,000 are currently described, making it likely that many of these unknown or undescribed fungi are represented only by eDNA data. For more than a decade mycologists have struggled with whether the International Code of Nomenclature for algae, fungi, and plants (the Code ) should allow for formal description of fungal taxa from eDNA data alone, i.e. with a DNA sequence serving as a type. It is, however, unlikely that an amendment to the Code with this provision will pass in the near future. It is therefore imperative to establish an informal yet structured naming system to allow unified communication about DFT. The system proposed herein applies most of the principles of the Code to generate designations that, while nomenclatorially invalid, can nonetheless be integrated into fungal classifications and diversity assessments. We used the 2025 Westerdijk Spring Symposium "DNA Sequences as Type" to bring mycologists together to work out community consensus-driven conventions and standards for what we call the International Standard to Catalogue Dark Fungal Taxa (ISCDFT). The established guidelines principally refer to naming conventions, quality and standards for the underlying data, and standards regarding the underlying analysis leading to the detection of new DFT. The ISCDFT does not compete with the Code but enables the community to catalogue DFT and integrate these into fungal classifications while adhering to broadly established principles. For ease of immediate implementation, we provide examples to illustrate these newly established guidelines, a checklist for publishing new DFTs under the ISCDFT, and convert some previously published fungal names based on eDNA sequences to ISCDFT-compliant names.

Guidelines for preparing and submitting proposals to modify or enhance Chapter F of the International Code of Nomenclature for algae, fungi, and plants are set out here. Such proposals will be considered by the Fungal Nomenclature Session of the XIII International Mycological Congress, to be held in Incheon, Korea in August 2027. A timetable is established for the submission of proposals, due by 31 December 2026, their publication in IMA Fungus, the release of the ‘Synopsis of proposals’ and the conduct of the pre-Congress guiding vote.

Summary: Ectomycorrhizal fungi (EMF) produce mycelia with variable extension and complexity, which can be classified according to soil ‘exploration types’ (ETs). ETs have received attention as one of the few mycorrhizal trait frameworks, but without an empirical classification of ET functional diversity and environmental preferences, understanding and interpreting EMF biogeographic patterns has been difficult. We conducted a synthesis combining: comparative EMF genomics to describe functional divergence in decomposition and nutrient cycling genes across ETs; and EMF trait distribution modeling across continental Europe, pairing soil and root EMF surveys to establish biogeographic ET niche profiles. We demonstrate a signature of ETs encoded in EMF genomes, which is independent from phylogeny and linked to biomass production strategies. EMF ET relative abundances were separated by soil, root, and dominant tree leaf type habitats and exhibited unique correlations with forest biotic (e.g. plant productivity and plant pathogen densities) and abiotic (e.g. nitrogen deposition and soil pH) conditions. These findings support a theory that EMF niche partitioning can be partially explained by extraradical mycelial traits, with underlying variation in ET biogeography likely arising from distinct decomposition and nutrient cycling potentials. We also identify important limitations to this trait framework and provide a guided outlook for future research.

Porpoloma Singer is a genus of mushrooms distinguished by a tricholomatoid habit and amyloid spores. The genus is restricted to temperate regions of the southern hemisphere, with currently accepted species known from New Zealand and South America. Apart from P. penetrans (Cleland) Grgur., which most likely does not belong in Porpoloma but is suggested to be a species of Heimiomyces Singer, no species of Porpoloma have been described from Australia. However, molecular phylogenetic analyses indicate the presence of at least nine species in Australia. Here, we describe P. flavilamellatum from sporing body material from New South Wales. The species is also detected from sequences generated from soil samples collected in Queensland. Porpoloma flavilamellatum is distinguished macroscopically from some members of the genus by having yellow lamellae, and by other members of the genus that also have yellowish lamellae (P. amyloideum (G. Stev.) E. Horak, P. coyan Garrido, P. sejunctum Singer) by having darker yellow lamellae, lacking a membranous annulus or zone on the stipe, and being found in habitats with Myrtaceae Juss. rather than Nothofagaceae Kuprian. It is distinguished from all other members of the genus Porpoloma by its unique phylogenetic position.

The taxonomy of Laccaria laccata, the type species of the genus Laccaria, has long been ambiguous due to the absence of a reference sequence and the reliance on early, morphology-based descriptions. To resolve this issue, we selected a Code-compliant lectotype for Agaricus laccatus—the basionym of L. laccata—from Schaeffer’s 1762 illustration cited in Fries’ sanctioning work. Given the limitations of this historical material for modern species interpretation, we also designated an epitype based on Singer’s collection C4083 (BAFC) from Femsjö, Sweden, which was previously but not effectively designated as the “lectotype” by Singer. This epitype is supported by detailed morphological descriptions, iconography, and newly generated nrITS, nrLSU, and RPB2 sequences, which have also been newly obtained from additional collections. Phylogenetic analyses consistently place the epitype of L. laccaria within a well-supported clade, herein designated as/Laccaria laccata, which includes sequences previously reported as falling within the “proxima 1 clade”. This integrative approach, combining historical typification with modern molecular and morphological data, stabilizes the nomenclature of L. laccata and provides a robust foundation for future studies of this ecologically and economically important genus of ectomycorrhizal fungi.

Many macrofungi are impractical or impossible to culture. Consequently, DNA for long-read sequencing required for the assembly of high-quality genomes must be isolated from samples taken from the environment. Collection is often in remote locations, limiting the options for stabilising samples to methods that do not require refrigeration. Fungi contain species-specific arrays of metabolites that may complicate purification techniques and call for judgement to be made to apply appropriate modifications to the DNA extraction protocol in specific cases. The protocols and commentary we describe are informed by the preparation of DNA from a range of Australasian ectomycorrhizal and saprotrophic macrofungi. We collect samples into isopropanol at ambient temperature and employ a strategy of chromatin isolation followed by the sequential removal of unwanted molecular components to purify DNA.

Procedures, appointments and outcomes of the Fungal Nomenclature Session (FNS) of the XII International Mycological Congress (IMC12) are summarized, including the composition of the Fungal Nomenclature Bureau and the Nominating Committee of the IMC. Between 124 and 322 mycologists attended the three sessions of the FNS, at which formal proposals to amend Chapter F of the International Code of Nomenclature for algae, fungi, and plants were debated. The 15 proposals considered included eight "from the floor", five of which were withdrawn prior to the FNS. One of the withdrawn proposals was directed to the Editorial Committee for Fungi, in relation to adding examples of best practice when citing living cultures as types. Among the seven proposals published in Taxon, one proposal with a high “no” vote in the Guiding Vote was not re-introduced. Discussion on one proposal led to the authorization of a Special-purpose Committees on “Genomes as Types for Fungi”. For the eight proposals that were put to a vote, two proposals were rejected and six proposals were accepted. The accepted proposals: (1) clarified that a proposal to conserve a name with a conserved type does not require citation of a typification identifier; (2) clarified procedures to protect and reject names of fungi; (3) removed the need to list synonyms of protected names in the Code appendices; (4) clarified that an earlier homonym of a sanctioned name remains unavailable if the sanctioned name is rejected outright; (5) recommended that culture collections or biological resource centres where cultures are lodged should be “public”; and (6) recommended that when original type cultures are lost, neotypification should utilize the progeny of ex-type cultures. Appointments made by the FNS included the Secretary of the Fungal Nomenclature Bureau for IMC13, the officers and members of the Editorial Committee for Fungi, and the officers and members of the Permanent Nomenclature Committee for Fungi. Decisions and appointments of the FNS were ratified in a resolution accepted by the plenary session of the Congress.