Twenty-nine new Entoloma species in one European revision

A hundred and eight pages of housekeeping

Twenty-nine species new to science, one new section, and sixteen older names finally tied to a specimen somebody can sequence: that is the yield of a revision of the genus Entoloma in Europe, published online in Persoonia on 13 February 2026 and carried in the issue dated 15 June 2026. It occupies pages 200 to 307 of volume 56, carries sixteen authors with Machiel E. Noordeloos and Bálint Dima at either end of the list, and works through fourteen clades of the genus at once. The new section is Entoloma sect. Atricoloria, MB 860448, named after its type species E. atricolor. The full text is open access.

Counting names rather than taxa gives a different total, and it is worth doing. Alongside the twenty-nine, the paper validates a thirtieth species name, Entoloma myochroum, published invalidly in 2004 and issued here as sp. nov. with its own MycoBank number, MB 860440. Two new sectional combinations and one replacement name follow. Thirty new species names are therefore validly published in this paper, not twenty-nine.

The authors are explicit about what the work is for. It anticipates the second volume of a completely revised monograph of the European species, in the Fungi Europaei 5 series; the first part appeared in 2022 and the second and final volume is planned to be finished during 2026. This is the groundwork, not the monograph.

What 694 sequences actually bought

Everything here rests on a single marker, the nrDNA ITS barcode. The team generated 694 new ITS sequences, eighty of them from type specimens, and combined those with 406 downloaded from GenBank and UNITE — around eleven hundred sequences in all. Separate trees were built for each major clade in RAxML after alignment in MAFFT and manual pruning in AliView, with a thousand rapid bootstrap replicates. Herbarium material was sequenced at the Naturalis Biodiversity Center on an Illumina MiSeq, amplifying ITS1 and ITS2 separately.

That is the practical shape of the phrase a new species was described. The holotypes of the twenty-nine were collected between 2005 and 2024: eight in Norway, seven in the Netherlands, four in Sweden, three in Russia, two in Germany, and one each in France, Italy, Hungary, Croatia and the United Kingdom. Entoloma weiriorum rests on a collection made on 20 September 2005 in open, mixed woodland at Eaves Wood, Silverdale, in West Lancashire (vice-county 60), by John and Sheila M. Weir. The specimen sits in the fungarium at Kew as K-M000141043, and it took twenty years to acquire a name.

Which is why discovery is the wrong word for most of this. The majority of these species are lineages separated out of material that had been filed for years under older names, in herbaria and in the literature. Of Entoloma cognatum, from a semi-natural pasture in Trøndelag, the authors say outright that it is hardly distinguishable morphologically from E. calaminare and E. velenovskyi yet phylogenetically distant from both. The smallest of the novelties, Entoloma pumilionis, has a cap between 1 and 3 mm wide; its holotype was collected by T. Hülsewig on 5 November 2022 from a roadside at Witten in North Rhine-Westphalia (specimen B 70 0105497, ITS sequence GenBank PX412063), and its epithet comes from the Latin pumilio, a dwarf.

Sixteen old names, pinned to a specimen

The second half of the paper adds no taxa at all. It repairs names that already existed. Sixteen of them are given a neotype, a lectotype or an epitype — a specimen the name now refers to, and one from which DNA can be read. Designating an epitype creates nothing. It settles what a name coined long before anyone thought about sequencing was actually meant to denote.

The spread of dates is the interesting part. Entoloma sericellum traces back to Agaricus sericeus ß sericellus, published by Elias Fries in 1818; no holotype ever existed, so the neotype is a collection made on 20 August 2016 at a roadside south of Alvdal in Norway (O-F-304566, ITS sequence PX412066). For Entoloma araneosum the lectotype is Lucien Quélet’s own 1877 plate, and the epitype is a collection Noordeloos made on 22 September 2003 in rich deciduous forest on calcareous soil at Oignies-en-Thiérache, in the Belgian province of Namur. The oldest basionym on the list, Agaricus byssisedus, was published by Christiaan Hendrik Persoon in 1800. Yet the same list contains Entoloma ollare, a name validly published only in 2004 because the 1992 publication is invalid. These classical names span rather more than two centuries, and calling them all nineteenth- and twentieth-century would be tidier than it is true.

The limits the paper states, and two it does not

It settles nothing about Polish records. The word Poland does not appear anywhere in the full text, no type specimen came from Poland, and no Polish collection is cited. Nor is the work confined to European ground. The holotype of Entoloma ostreatum was collected on 26 August 2013 in the Sikhote-Alin Nature Reserve in Primorsky Krai, and the authors give the range of that species as Mediterranean to subalpine Europe and North Asia or the Russian Far East. Two further holotypes, E. bresadolae and E. ludwigii, were gathered on 23 August 2024 from a steppe meadow in Sverdlovsk Oblast, in the Urals.

The abstract disagrees with the body of the paper in two places, and knowing about them beats repeating them. E. ostreatum appears both among the twenty-four names said to have received new type sequences and among the twenty-nine new species, yet the body treats only one E. ostreatum, the new taxon MB 860390. The real number of pre-existing names given a new type sequence is therefore twenty-three at most. Similarly, the replacement name is printed in the abstract as E. cobaltichlorum and in the body as Entoloma cobaltichroum, MB 860447, a replacement for E. dichroides with a Vietnamese type — and it is the body form that carries the MycoBank number and the protologue. Each spelling occurs exactly once in the paper.

The trees have limits the authors do not hide. They judge the species-level clades generally well supported, but the backbone of the overview tree has low support throughout, the clades of E. sericellum and E. undatum are poorly supported, and within the E. velenovskyi and E. ostreatum clades there are distinct subclades that may yet prove to be separate species. Sequencing of the E. myochroum holotype — a 1990 collection from a beech wood in the Eifel — failed with both Sanger and next-generation methods. That name is now valid, but it is anchored to a specimen from which no DNA could be read.

Two further things this paper does not say. It says nothing about edibility. The genus contains seriously poisonous species, but Entoloma sinuatum occurs once in the whole text, purely as a comparison of habit under E. myochroum. It is not revised here, and nothing in this work supports any statement about which Entoloma may be eaten. The paper also cannot be reproduced: Persoonia 56 is issued under CC BY-NC-ND 4.0, which forbids commercial use and derivative works, so none of its plates can be re-hosted here. The photograph at the head of this entry therefore comes from an entirely different source and shows an entirely different species.

What a reader can check

This revision is unusually easy to audit. Every novelty carries a MycoBank number, a specimen number in a named fungarium and a sequence accession — for E. pumilionis, MB 860436, B 70 0105497 and PX412063 respectively. The Crossref record confirms the pagination, the issue and the June print date. Paste the GenBank accession into a search box and the few hundred bases the whole description rests on come straight back.

For anyone who walks past these mushrooms, the lesson is prosaic and fairly demanding. A great many Entoloma on a meadow or in leaf litter cannot be settled from a photograph; the authors say as much about E. cognatum, where morphology simply does not separate the species. If one habit is worth carrying away from this, it is describing a fresh fruit body in the field — colours fade first — and keeping the dried specimen afterwards. That is precisely how the material behind these hundred and eight pages was assembled: collections photographed where they grew, their surrounding vegetation noted, described immediately after collecting, and dried into fungaria. The cover photograph has exactly that pedigree — specimen TUF124715 in the TUF fungarium at Tartu, with its own ITS sequence in UNITE.