R. K. GREVILLE’S FUNGUS NAMED “ORANGE SCLEROTIUM ” IS SHOWN TO BE A MEMBER OF THE BOLETALES (FUNGI: BASIDIOMYCOTINA)

Morphological and molecular data show the orange sclerotia depicted in Plate 101 of R. K. Greville’s Scottish Cryptogamic Flora to be a species of Penttilamyces (Coniophoraceae: Boletales), which is described here as new to science.


Introduction
Sclerotia are the vegetatively produced resting structures of various fungi.Considered by the early classical authors to be specific entities in themselves, they were given binomials and placed in what is today considered a polyphyletic genus: Sclerotium Tode.In early mycological research, connections were not made between Sclerotium and any sexual stage of a taxon.However, since the classical (early post-Linnean) period, many connections between the two have been established.Recent research has shown that sclerotia function as sexual structures in various, often unrelated fungi in genera ranging from the basidiomycetous to the ascomycetous.Examples in the Basidiomycotina include Athelia Pers.(Atheliales) (Julich, 1972), Collybia (Fr.) Staude (Agaricales) (Hansen & Knudsen, 1992), Sistotrema Pers.(Sistotrematales) (Eriksson et al., 1984) and, in the clavarioid fungi, Typhula (Pers.)Fr. (Corner, 1950).In the micro-fungi, examples are found in the Sclerotiniaceae (Helotiales) (Dennis, 1968) and Venturiaceae, specifically the single species of the bizarre genus Lasiobotrys Kunze, which relies for reproduction on aerial dispersal of its sclerotia (Dennis, 1968).Even some of the Myxogastrales (slime moulds) produce sclerotia (Alexopolous et al., 1996).
Sclerotia vary in size and morphology, ranging from the lentil-or apple pip-like structures of Collybia to small aggregates of cells found in cultures of Coprinopsis cinerea (Schaeff.)Redhead, Vilgalys & Moncalvo (Watling & Moore, 1994).They may be smooth or slightly pubescent, regular in outline or nodulose, pale or dark, and orange to brown and even black.In Typhula the interlocking hyphae on the surface, when viewed under a low-power microscope, have been shown to be diagnostic because they make different patterns depending on the species.
The Leucogyrophana group Ginns (1968Ginns ( , 1971) examined all the then-known species of Leucogyrophana, recognising eight species, to which was added L. lichenicola Thorn, Malloch & Ginns (Thorn et al., 1998).Since the recognition of that latest species, Leucogyrophana as been subdivided, and the independent genus Penttilamyces has been segregated from it based on the findings of molecular phylogenetic studies (Zmitrovich et al., 2019).
Penttilamyces has been found to belong to the Coniophoraceae, an entirely separate family to that containing the type species of Leucogyrophana (Hygrophoropsidaceae).Included in the new genus, Penttilamyces, are other former members of the genus Leucogyrophana, namely L. olivascens (Berk.& M.A.Curtis) Ginns & Weresub and L. romellii Ginns.Of these, Leucogyrophana olivascens forms sclerotia but they are dark brown, differing dramatically from the brightly coloured ones of L. lichenicola.Finally, in Leucogyrophana sensu Ginns & Weresub, L. pinastri (Fr.)Ginns & Weresub also possesses sclerotia, but in that species they are quite different in morphology, especially in being much more elongate (Ginns & Weresub, 1976).This character, coupled with the morphology of the hymenophore, indicates that there might be an additional grouping within Leucogyrophana.Indeed, molecular studies (Jarosch & Besl, 2001) have found it to represent a third genus, namely Hydnomerulius Jarosch & Besl in the paxilloid fungi (Paxillaceae; Boletales).
It is clear that Leucogyrophana, as conceived by Ginns (1968Ginns ( , 1971)), is polyphyletic and contains three genera in three totally different families, although all in the Boletales.Leucogyrophana lichenicola is now placed in Penttilamyces, which until this taxon was recognised, consisted exclusively of species associated with conifers.Recently, Leucogyrophana lichenicola was found in a blanket bog at the base of decaying stems of what was probably Cladonia ciliata Stirt. in Caithness, Scotland (P.D. Crittenden s.n., 26 vi 2013, E [barcode E00661348]).
The bright-orange Sclerotium had been collected, by Greville's "scientific and highly esteemed friend" Dr W. C. Trevelyan, from Trichostomum Bruch growing at the summit of Beinn Resipol ("Ben-Reishapol"), Loch Sunart, Ardnamurchan, in the Scottish Highlands.Greville (1824a), in his Scottish Cryptogamic Flora, cited it as a synonym of Sclerotium subterraneum Tode, under the name S. muscorum Pers., an early epithet also used by de Candolle (1807).However, in Flora Edinensis (Greville, 1824b), he followed Persoon (1801) in using, for the same fungus, the name Sclerotium subterraneum, but the original description given by Persoon would appear to be based on a fungus with slightly different features.Greville (1824aGreville ( , 1824b) ) probably included more than one species under this name, because he described Sclerotium subterraneum, in addition to being found in the mountains, also growing nearer sea level up tree bases and "on the lower, half-rotten stems of mosses".In Flora Edinensis (Greville, 1824b), he mentions that "when growing on roots or tree-bases it is somewhat larger and of a paler colour and white within".J. Hedger (Dundonell, personal communication, 1982) described a collection, made by J. Rishbeth, that was growing up the base of a Sequoiadendron J.Buchholz previously killed by Armillaria (Fr.) Staude; this was a pale-yellow sclerotium that was subsequently found to be the sclerotia of Collybia cookei (Bres.)J.D.Arnold.Material of Sclerotium subterraneum cited in Greville's Flora Edinensis has been traced in the Herbarium of the Royal Botanic Garden Edinburgh (E) and is more in keeping with Hedger's collection than Trevelyan's Scottish collections, the latter of which unfortunately cannot be traced.
The aim of our study was to identify, using morphological and molecular tools (ITS nrDNA sequences) a recent collection of a bright-orange Sclerotium found buried in specimens of moss cushions held in E.

Materials and methods
Collections from across Scotland and England held in E were included in this study (see below).Morphological analyses were carried out following Corner (1950).Material from one collection (Watling Wat. 30231) was subjected to molecular analysis, DNA isolation, sequencing and phylogenetic analyses, following the methods described by Ortiz-Rivero et al. (2021), which have previously been successfully applied to other members of the Boletales.
The consensus sequence was aligned with homologous sequences obtained from the GenBank DNA database.Leucogyrophana mollusca (Fr.)Pouzar and Hydnomerulius pinastri (Fr.)Jarosch & Besl sequences were included as outgroups.The alignment was analysed using a heuristic search option with maximum parsimony and maximum likelihood, using PAUP version 4.0a 147 (Swofford, 2003).Moreover, using the software MrBayes version 3.2 (Ronquist et al., 2012), a Bayesian analysis was carried out.Phylogenetic trees were generated using Tree View (Page, 1996) and edited using Adobe Illustrator CS3 version 11.02 (Adobe Systems).

Conclusion
Greville's interpretation of Sclerotium muscorum in his coloured illustration appears to be a specific bryophilous fungus that, in 1824, was lacking any known teleomorphic stage.Through molecular analysis, it has been ascertained that our fungus is a basidiomycete related to Penttilamyces lichenicola, but because of differences in the molecular sequence data between our bryophilus fungus and the lichenicolous taxon described from Canada, we have proposed it as a new species.

Figure 2 .
Figure 2. Sequence data for type material of Penttilamyces ginnsii compared with those for P. lichenicola and species previously placed in Leucogyrophana.