shelbourne's Journal

• First mention of this group is from North America by Peck (1874) as Agaricus geophyllus var. lilacinus. Gillet (1875) soon formalised the new combination as Inocybe geophylla var. lilacina (incorrectly using lilacinus).
• Kauffman (1918) promoted the variety to a new species, I. lilacina, suggesting it did not grow with I. geophylla in Michigan (US), and the colour difference was morphologically distinct.
• Traditionally placed alongside I. geophylla in section Tardae and subsection Geophyllinae.
• The separation from I. geophylla has not been followed by every author, but the US name has now been broadly applied to collections from across the world.
• Matheny and Swenie (2018) construct a phylogeny of subsection Geophyllinae using regions of ITS, 28S, and rpb2, and confirm that I. lilacina is a complex, and clades separately to the I. geophylla complex.
• Within complex I. lilacina, there are two European lineages that do not clade with collections from other continents or each other. As I. lilacina is a North American name, they are labelled I. lilacina sensu Larsson I and II, presumably after the 2012 description in Funga Nordica. Note that I. lilacina sensu Larsson I, includes a collection from Scotland.
• The geographic separation of species in the complex is interesting, especially considering that I often find basidiomes from complex I. lilacina with those from complex I. geophylla in the UK, and this contrasts with Kauffman’s observation in North America.
• A new species, I. ionolepis (2020), has recently been described from the UK and the Netherlands. This is also placed in complex I. lilacina and is violaceous but has distinct scales on the pileus.
• Other new European taxa have also been proposed, but no name or morphological distinctions have been proposed for either of the two mysterious European species.

References:

Matheny, P. B., & Swenie, R. A. (2018). The Inocybe geophylla group in North America: a revision of the lilac species surrounding I. lilacina. Mycologia, 110(3), 618-634.
Cullington, P., & Larsson, E. (2020). Inocybe ionolepis in Crous et al. Fungal Planet description sheets: 1112-1181. Persoonia 45:251-409.

On several occasions I have observed pluteoid basidiomes with dark yellow-brown to yellow pilei and whitish stipes, fruiting around the same well-rotted stump of a deciduous tree in semi-ancient mixed deciduous woodland. Genus of wood unknown.

Initially, I wanted to say these were Pluteus chrysophaeus, but then I read that some authors consider this a synonym of Pluteus chrysophlebius. So, I had to investigate a bit more.

https://www.inaturalist.org/observations/175925918
https://www.inaturalist.org/observations/186412237

The genus:

• Pluteus is a classical genus described by Fries in 1836 and is typified by P. cervinus, which was originally described by Schaeffer from Germany in 1774.
• Quite large, estimated to contain over 300 species, grouped into three sections, which also have various historical subsections.
• Worldwide distribution, and some species appear to have inter-continental ranges.
• Saprotrophic on wood, generally preferring well-rotted wood, the spore deposit is ‘pink’ to buff, there is no ring or other remnants from a veil, and the gills are broad, free, and crowded.
• The spores are generally smooth and round to ellipsoid, often with large guttales (vacuoles).
• Common names include ‘Shields’ and ‘Deer Mushrooms’.
• Some species are reported to be edible but not choice, and others to have low levels of psychoactive toxins like psilocybin.

Yellow species:

• Specimens with gold, yellow, yellow-brown, or greenish-yellow colours are now usually classified into four species:

1. P. leoninus (Shaeff., 1774) P. Kumm. (1871), described from Germany.
2. P. chrysophaeus (Schaeff., 1774) Quel. (1872), described at the same time as P. leoninus from Germany.
3. P. chrysophlebius (Berk. & Ravanel, 1859) Sacc. (1887), described from South Carolina, North America. [Sometimes still called P. admirabilis (Peck, 1872) Peck (1885) in the US, although widely synonymised in the literature after Smith (1956)].
4. P. rugosidiscus Murrill (1917), described from New York, North America.

• P. leoninus is in section Hispidioderma, and it can be distinguished by microscopic characters (pileipellis a trichoderm) and sometimes on macroscopic characters (pileus colour and texture, and basidiome stature).
• The other three species are in section Celluloderma (hymeniderm of short elements), and also within the same clade in the section (this clade has no reported morphological distinctions).

Problems circumscribing species in the chrysophaeus/phlebophorus-clade:

• There has traditionally been considerable confusion about P. chrysophaeus and the closely related P. phlebophorus (Ditmar, 1813) P. Kumm. (1871). There are no type specimens for either of these concepts, and the original descriptions are brief and lack any modern (or microscopic) characters.
• P. phlebophorus is usually taken to have a browner pileus (and often more venose) like the illustration given with the protologue.
• P. chrysophaeus is originally described by Schaeffer as having ‘gold-saturated’ pileus, and the specific epithet translates to ‘dusky-gold’.
• The illustration of P. chrysophaeus (now designated lectotype by Justo et al., 2011a), appears to show an immature basidiocarp with a brownish-yellow pileus.
• To complicate matters further, later descriptions by Fries, Quelet (1872), and Saccardo (1887), describe the colour as ‘dark cinnamon’ or ‘brownish’.
• Vellinga (1990) presents a more detailed morphological concept for P. chrysophaeus in Europe that includes microscopic characters. She describes the pileus as olive-yellow when moist and yellowish-ochraceous brown, and also includes greenish-yellow in her key.
• Vellinga describes the micromorphology of P. chrysophaeus as variable and synonymises the three concepts of Orton (1960): P. galeroides, P. luteovirens, and P. xanthophaeus.
• Vellinga comments that her description (based on collections from NL, UK, and GER) is a good fit for Schaeffer’s protologue, although she does not give his illustration as a selected icon.
• As a result of the confusion over the lectotype and the more brown description of the pileus in some historic descriptions, several authors (Smith, 1956; Orton, 1960; and Kibby, Burnham & Henrici, 2010) suggest that P. chrysophaeus is widely synonymous with P. phlebophorus and any other sense of the name should be abandoned due to confusion.
• Kibby, Burnham and Henrici (2010) also suggest that another name from Orton, like P. luteovirens, could be revived if necessary.
• Although it is not discussed in the literature, there is a noticeable difference in the stated proportions of basidiomes given in description of Saccardo (1887) compared to Vellinga (1990), which also encourages me to think that later authors may have confused Schaeffer’s species with others in the C/P clade or even other clades.
• Minnis and Sundberg (2010) share the view that P. chrysophaeus is confused, and suggest P. chrysophaeus sensu Vellinga (1990) and P. rugqosidiscus are synonymous under P. chrysophlebius, reporting no distinguishing morphological differences.

More recent work:

• Justo et al., (2011a) present a phylogeny for Pluteus based on ITS, and Justo et al., (2011b) extend this to consider nSSU and nLSU.
• These phylogenies support the traditional sections (with some exceptional species moved to Celluloderma), but the organisation of sections into natural subsections is not clear.
• Within section Celluloderma, the chrysophaeus/phlebophorus (C/P) clade seems to have significant support and includes the collections identified as P. phlebophorus, P. chrysophaeus, P. chrysophlebius, and P. rugosidiscus (and their accepted synonymies).
• Sevcikova and Bovrika (2019) present a wider ITS-based phylogeny of the C/P clade and a few observations of differences in other genes.
• Both P. phlebophorus and P. rugosidiscus seem to have more distinct positions compared to the other species in the C/P clade, and P. phlebophorus is generally associated to a distinct and distinguishable species.
• Notably the holotypes for P. chrysophlebius and P. rugosidiscus have not been sequenced, and no type specimens have been designated for those without one
• Justo et al. (2011a) continue with the idea that P. chrysophaeus sensu Vellinga (1990) is synonymous with P. chrysophlebius, describing an intercontinental species, and reporting that the inter-continental variation in ITS is less than 2%.
• Collections in the chryophaeus/chrysophlebius (C) subclade, or complex, form geographical clades, and the sample size in Justo et al. (2011a) does not seem significant enough to determine the variance. Sevcikova and Bovrika (2019) also seem to disagree that the matter is settled.
• In much of the criticism of P. chrysophaeus there is a lot of focus on the perceived mismatch between the (designated) lecotype and the protologue.
• In my view, the protologue and specific epithet should have priority over the illustration, and regardless, the illustration still fits within the description and seems to correspond to collections from Europe and North America (even if it may not be best single specimen for identification).
• The specimens from the C complex that I have observed had brownish immature pilei and yellow mature pilei in the same group. This is also reported by Sevcikova and Bovrika (2019) in Europe and Micheal Kuo in North America (in the description of P. chrysophlebius on his website).
• I would be reluctant to abandon Schaeffer’s name (which has been used for many years in Europe and Asia), based on the potential criticisms of the lectotype, and the synonymy of later descriptions with brown species. P. chrysophaeus is the youngest name in the clade and would also have priority over P. chrysophlebius in a synonymy.
• P. rugosidiscus has recently been found in Europe for the first time, reported in Sevcikova and Bovrika (2019), and a more detailed ITS-based phylogeny of the C/P clade still supports a separate but cryptic species.
• This species is said to be characterised by green colours in the pileus, although Vellinga (1990) includes greenish-yellow in her key to P. chrysophaeus, and Sevcikova and Bovrika (2019) conclude that this is not a distinguishing feature based on ITS.
• Sevcikova and Bovrika (2019) question some of the historic synonymies in the C complex, on the basis of morphology, and suggest that more work is needed to decide on some of Orton’s concepts (1960).
• No clades for these species are represented in the current phylogenies but the variability of the groups on the C/P clade suggests careful analysis of molecular data to obtain a significant understand of the relationships.
Conclusion:
• Section Celluloderma requires more molecular data across more species to achieve a clearer understanding of the relationships between the clades.
• Biological/mating studies for the different clades would be helpful.
• For the C complex, without more molecular data across more collections (including the holotype of P chrysophlebius), it seems difficult to decide whether there are one or more species (e.g. North American and European/Asian) or even some that have not been sequenced.
• Unless future morphological studies can determine more distinguishing characters, then the species in the C complex would appear to be cryptic - only distinguished by molecular data or geography.
• Recent results suggest P. rugosidiscus could represent another cryptic species in the C/P clade, which can only be reliably distinguished by ITS.

References:

Bas, C., Kuyper, T., Noordeloos, M., Vellinga, E., Boekhout, T. & Arnolds, E. (1990). FLORA AGARICINA NEERLANDICA: Critical monographs on families of agarics and boleti occurring in the Netherlands, vol. 2.
Justo, A., Minnis, A.M., Ghignone, S. et al. (2011a). Species recognition in Pluteus and Volvopluteus (Pluteaceae, Agaricales): morphology, geography and phylogeny. Mycol Progress 10, 453–479.
Alfredo Justo, Alfredo Vizzini, Andrew M. Minnis, et al. (2011b). Phylogeny of the Pluteaceae (Agaricales, Basidiomycota): taxonomy and character evolution. Fungal Biology, 115(1), 1-20.
Justo, A., Malysheva, E., Bulyonkova, T. et al. (2014). Molecular phylogeny and phylogeography of Holarctic species of Pluteus section Pluteus (Agaricales: Pluteaceae), with description of twelve new species. Phytotaxa, 180(1), 1-85.
Geoffrey Kibby, Antony Burnham, Alick Henrici, (2010). Some problems in the genus Pluteus, Field Mycology, 11(3), 93-100.
Minnis, A. M., & Sundberg, W. J. (2010). Pluteus section Celluloderma in the USA. North American Fungi, 5, 1-107.
Nelson Menolli Jr. , Tatiane Asai & Marina Capelari (2010). Records and new species of Pluteus from Brazil based on morphological and molecular data, Mycology, 1:2, 130-153, DOI: 10.1080/21501203.2010.493531
Orton, P.D. (1960). New check list of British Agarics and Boleti: part III. Notes on genera and species in the list. Trans. Brit. Mycol. Soc. 43 (2): 359–360.
Ševčíková, Hana; Bororvička, Jan (2019). Pluteus rugosidiscus (Basidiomycota, Pluteaceae), first record of this North American species in Europe. Nova Hedwigia, 108(1), 227–241.
Ševčíková H, Malysheva E, Ferisin G, Dovana F, Horak E, Kalichman J, Kaygusuz O, Lebeuf R, González GM, Minnis AM, et al. Holarctic Species in the Pluteus romellii Clade. Five New Species Described and Old Names Reassessed. Journal of Fungi. 2022; 8(8):773.

• I recently collected several basidiomes that I determined are from genus Hebeloma, but upon further reading I realised that this is a large and rather complex genus.
• Species and even section determination usually requires microscopic examination of spores and cystidia, and there are some difficult and variable species that are not currently resolved by ITS.
• Estimates of around 150 species, in 17 sections, a few with subsections too. Associated with a wide range of trees and shrubs, could be restricted for some species but data is often missing historically or less reliable.
• Worldwide distribution, found in many woodlands, especially in arctic and alpine regions, also common in boreal and temperate regions, and rare in tropical regions.
• Originally described as Agaricus tribus Hebeloma by Fries in 1821 and elevated to genus by Kummer in 1871.
• Typified by Hebeloma mesophaeum since 2013, apparently there was too much controversy around the original type, Hebeloma fastibile (Agaricus fastibilis), based on the original 1801 description of Persoon.
• Currently placed in the family Hymenogastraceae.
• The Latin name translates to ‘Fringe of Youth’, relating to the cortina-like veil found on immature basidiomes of many species in the genus.
• Generally reported as inedible and some as poisonous, common names include ‘Poison Pies’ and ‘Dull Caps’.
• I found the website hebeloma.org, which is an incredible resource, summarising many years of research on the genus, designating types, and describing sections and species.
• All the species descriptions are very detailed, and dynamically parameterised by a database of collections, which contains over 10,000 observations across 120 species. Almost all observations have an associated ITS sequence and many have sequences for other loci too.
• Culmination of decades of work on Hebeloma by H. J. Beker, U. Eberhardt and J. Vesterholt in Europe (2016) and more recently North America.
• Morphology page that explains how to measure, describe, and record morphology (macro and micro) of collections.
• Observations are stored in a dedicated biological database, which also back-ends the website, this allows queries to find certain types of observations and patterns, or to compare the characteristics of a new observation.
• I really like the comprehensive and systematic approach to studying the genus, and the use of morphology, geography, and phylogeny to describe and delimit the sections and species.
• Important features identified for determination of sections and species:
o Geographic location.
o Number of complete lamellae.
o Spore ornamentation, size, and perispore loosening.
o Cheilocystidia shape, length, apical width, and ratios.
• An automatic identifier has been trained on some of the data using machine learning and is available on the website. If some of these features are entered into a form, then suggestions of sections and species with different certainties are generated from the database.
• In testing, the auto-identifier was found to be over 75% accurate for giving the correct species (as determined by expert and molecular analysis) as the top suggestion, and over 95% accurate for giving the correct species in the top 5 suggestions.

www.hebeloma.org

H. J. Beker, U. Eberhardt and J. Vesterholt (2016). Hebeloma (Fr.) P. Kumm., Fungi Europaei vol. 14. Canduso Edizioni.

• Researchers from University of Tennessee (US) and Universidad de Alcala (Spain) propose a reorganisation of genus Inocybe, the culmination of several publications which have shown the genus to be paraphyletic.
• ‘New skin for the Old Ceremony’ is from the title of the article and is the title of Leonard Cohen’s fourth album.
• Inocybe (s.l.) is a hyperdiverse genus, estimated to contain 1050 species, mostly LBMs that can be challenging to identify morphologically - even with microscopic characters.
• First described as Agaricus tribus Inocybe by Fries in 1821, and elevated to genus by Fries in 1863, it is typified by Inocybe relicina (Agaricus relicinus) that was described by Fries at the same time.
• Spent some time in Cortinariaceae before becoming the type genus of the family Inocybaceae, still some questions in the literature regarding relationship between Crepidotaceae and Inocybaceae.
• The genus has a worldwide distribution, grows terrestrially on soil, and is associated with up to 23 families of vascular plants (related to diversity?).
• New species regularly being found around the world, even in Europe.
• Common name is usually ‘Fibre Caps’, which is a translation of the Latin name, or some reference to the fibrous texture of the pileus found in many species.
• Rarely eaten because many species produce secondary metabolites such as muscarine and psilocybin, and some are deadly. This is particularly dangerous considering the difficulty of species determination.
• Notoriously difficult to culture by subculturing/cloning or germinating spores, which has only added to the complexity of elucidating the species diversity.
• To build phylogeny, six genes sequenced for 54 taxa from Inocybaceae: rpb1, rpb2, tef1, 28S, 18S, 5.8S.
• Seven genera are suggested: Newly defined Nothocybe and Pseudosperma, elevated Inosperma and Mallocybe, previously suggested Auritella and Tubariomyces, and the remaining Inocybe s.s.
• The suggestions have been adopted quickly in the literature, and it seems to be a broad improvement in relating the taxonomy to the phylogeny and reflecting the diversity and relationships more clearly.
• Some of the new genera are strongly supported, but there still seems to be uncertainty about some of the precise relationships. Although this should improve as more species are discovered and greater penetration is achieved for the smaller genera.
• Important features for distinguishing new genera:
o Existence of pleurocystidia.
o Shape of basidia.
o Spore shape.
o Texture of stipe apex.
o Texture of the pileus.
o Colour of basidiome (rubescent or brunnescent).
o Length of cheilocystidia.

P. Brandon Matheny, Alicia M. Hobbs & Fernando Esteve-Raventós (2020). Genera of Inocybaceae: New skin for the old ceremony, Mycologia, 112:1, 83-120, DOI: 10.1080/00275514.2019.1668906
http://inocybaceae.org/.../Matheny_GeneraInocybaceae_2020...

Liimatainen, K., Kim, J.T., Pokorny, L. et al. Taming the beast: A revised classification of Cortinariaceae based on genomic data. Fungal Diversity 112, 89–170 (2022).

• Cortinarius is the last genus supported in Cortinariaceae, and largest in Agaricales: 5000[?] taxa in Species Fungorum in 2021, 172 sections defined in recent studies.
• Time for a split?
• Targeted capture sequencing, first time for Basidiomycetes, and shallow whole genome sequencing.
• 75 single-copy genes from 19 species (for backbone tree), wider 5-locus (RPB1, RPB2, MCM7, GPD, and TEF1) analysis of 245 species (for primary phylogenetic tree). Interestingly, ITS is not used.
• In both trees, many of the clades are strongly supported, but some supports are weaker, particularly as you move down the trees.
• Suggested split into ten genera: Cortinarius (s.s.), Phlegmacium, Thaxterogaster, Calonarius, Aureonarius, Cystinarius, Volvanarius, Hygronarius, Mystinarius, and Austrocortinarius. Seven new genera, lots of new subgenera and sections.
• A few genera still dominate, especially Cortinarius (s.s.) with more than 2000 species, and Cortinarius Subg. Telamonia still has 80 sections.
• Now I'm wondering when it will be (broadly) accepted and how much impact will it have on identification for different purposes?

https://link.springer.com/article/10.1007/s13225-022-00499-9
Nice discussion: https://karl.soop.se/KS60_JEC22_Eng.pdf

• In order Cantherellales and family Hydnaceae, typified by the classical H. repandum that was first described by Linnaeus in 1753.
• The genus has been collected and consumed by humans for centuries, with commons names such as “Hedgehogs”, “Sweet Tooth”, and “Wood Urchins”.
• A paper in 2009 looked at ITS for the genus and found a lot more diversity than accounted for by the described species.
• In 2018, this diversity was addressed using a broader study of morphology and ITS (46 sequences from 18 species and good quality sequences in UNITE and GenBank), leading to 49 species, with 22 newly described.
• Traditionally three species in Europe, now four subgenera: Alba, Pallida, Hydnum, Rufescentia (in order of diversity).
• The genus and lower orders generally have a worldwide or broad distribution, but species seem to be separated by continent.
• Few morphological characters: Pileus and hymenium colour, central depression of pileus, basidiocarp proportions and regularity, attachment of hymenium to stipe, spore shape and size.
• Distinguishing between subgenera, sections, and subsections, can require microscopy of the spores, and distinguishing between species in some groups and geographical regions requires ITS.
• Both subgenera Hydnum and Rufescentia are particularly diverse and have species that overlap in morphology.
• H. reginae was recently described from the UK, and analysis of ITS and LSU suggests this is the European H. cf. albidum, and H. albidum s.s. is an American species.
• H. reginae is placed in subgenus Alba and seems to be more closely related to the species around H. cremeoalbum.
• This analysis of ITS and LSU for subgenera Alba, Pallida, and Hyndum provides further support, although support for Alba is still relatively weak.

UK situation, records checked in GBIF (some could be missing):

• H. repandum (Subgenus Hydnum: Section Hydnum): ~2,000 records.
• H. rufescens (Subgenus Rufescentia: Section Rufescentia: Subsection Rufescentia): ~700 records.
• H. ellipsosporum (Subgenus Rufescentia: Section Rufescentia: Subsection Tenuiformia): One record from Wales, but CBIB considers the species widespread and suggests that it has been mistaken for H. rufescens.
• H. c.f umbilicatum (Subgenus Rufescentia: Section Rufescentia: Subsection Tenuiformia): Apparently records elsewhere, European concept.
• H. reginae (Subgenus Alba): No records but described from the UK, considered rare in the UK as noticeably different to other species present.

I wonder if the novelty of the species and difficulty of separation could mean that more European species are present. I guess sequencing the ITS from more UK collections would help.

Literature:

Grebenc, T., Martín, M. P., & Kraigher, H. (2009). Ribosomal ITS diversity among the European species of the genus Hydnum (Hydnaceae). Anales Del Jardín Botánico De Madrid, 66(S1), 121–132. https://rjb.revistas.csic.es/index.php/rjb/article/view/333/327

Niskanen T, Liimatainen K, Nuytinck J, Kirk P, Ibarguren IO, Garibay-Orijel R, Norvell L, Huhtinen S, Kytövuori I, Ruotsalainen J, Niemelä T, Ammirati JF, Tedersoo L. (2018). Identifying and naming the currently known diversity of the genus Hydnum, with an emphasis on European and North American taxa. Mycologia, 110(5), 890-918. http://www.nlmushrooms.ca/science/2018%20Identifying%20and%20naming%20the%20currently%20known.pdf

Kibby, G., and Liimatainen, K. (2022). Hydnum reginae newly described from Britain. Field Mycology, 23(3), 77-80. https://www.britmycolsoc.org.uk/application/files/9916/5937/2438/Field_Mycology_Vol_233_August_2022.pdf