doi:10.5598/imafungus.2018.09.02.04 IMA FUNGUS · 9(2): 271–290 (2018) Diversity of Chroogomphus (Gomphidiaceae, Boletales) in Europe, and ARTICLE typification ofC. rutilus Ross Scambler1,6, Tuula Niskanen1, Boris Assyov2, A. Martyn Ainsworth1, Jean-Michel Bellanger3, Michael Loizides4 , Pierre- Arthur Moreau5, Paul M. Kirk1, and Kare Liimatainen1 1Jodrell Laboratory, Royal Botanic Gardens, Kew, Surrey TW9 3AB, UK; corresponding author e-mail: [email protected] 2Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences, 2 Gagarin Str., 1113 Sofia, Bulgaria 3UMR5175, CNRS, Université de Montpellier, Université Paul-Valéry Montpellier, EPHE, INSERM, 1919, route de Mende, F-34293 Montpellier Cedex 5, France 4P.O. box 58499, 3734 Limassol, Cyprus 5Université de Lille, Fac. Pharma. Lille, EA 4483 IMPECS, F – 59000 Lille, France 6 Present address :Department of Applied Sciences, University of the West of England, Frenchay Campus, Coldharbour Lane, Bristol, BS16 1QY, UK Abstract: In this study, eight species of Chroogomphus are recognized from Europe: C. britannicus, C. aff. Key words: filiformis 1, C. fulmineus, C. cf. helveticus, C. mediterraneus, C. cf. purpurascens, C. rutilus, and C. subfulmineus. DNA barcode Different candidates for the application of the name C. rutilus are evaluated and the best fit to the description is ITS selected; lecto- and epitypes are chosen to fix the name. Chroogomphus fulmineus and C. mediterraneus are molecular systematics also epitypified and a new species, C. subfulmineus, is described. The infrageneric classification is revised and new taxa a new subgenus Siccigomphus and three new sections, Confusi, Filiformes, and Fulminei are introduced. The taxonomy former sections Chroogomphus and Floccigomphus are elevated to subgeneric level. Comparison of the ITS regions (nuc rDNA ITS1-5.8S-ITS2) of all species studied shows that there is a minimum interspecific difference of 1.5 %, with the exception of the two species belonging to sect. Fulminei which differ by a minimum of 0.9 %. Ecological specimen data indicate that species of Chroogomphus form basidiomes under members of Pinaceae, with a general preference for species of Pinus. Five European species have been recorded under Picea, while Abies and Larix have also been recorded as tree associates, although the detailed nutritional relationships of the genus, involving other suilloid fungi in particular, have yet to be fully clarified. Article info: Submitted: 27 November 2017; Accepted: 27 August 2018; Published: 5 September 2018. INTRODUCTION (originally recognised as a subgenus of Gomphidius), with non-gelatinised, tomentose to fibrillose innate hyphae in the Originally a subgenus of Gomphidius (Singer 1948), pileipellis (Miller 1964). However, these divisions have since Chroogomphus was elevated to generic status by Miller been shown not to represent monophyletic lineages (Li et al. (1964). More recent molecular analyses have shown the 2009). Chroogomphus also includes one species, C. albipes, genus to be monophyletic (Miller & Aime 2001, Miller 2003, Li which is currently unique in the genus due to the secotioid et al. 2009). Species of Chroogomphus are characterized by basidiomata. Because of this and other unusual morphological basidiomata with pale orange to ochraceous lamellae when characters, this species was originally described as Secotium young, an ochraceous pileal trama, a moist to viscid pileipellis, albipes (Zeller 1948) and then recombined as Brauniellula an ephemeral fibrous veil, and hyphae at the base of the stipe albipes (Smith & Singer 1958); however, molecular studies that have an amyloid reaction in Melzer’s reagent. By contrast, have shown that it belongs to Chroogomphus (Miller 2003, species of the sister genus Gomphidius are characterised Li et al. 2009). Brauniellula would normally have priority over by basidiomata with pallid to white lamellae when young, a Chroogomphus, but the latter name was conserved over it by pallid to white pileal trama, a glutinous pileipellis and veil and Aime & Miller (2006); it is now accepted as the correct name non-amyloid to dextrinoid hyphae at the base of the stipe of the genus. (Miller 1964, Miller & Aime 2001, Li et al. 2009). Both genera Six species currently assigned to Chroogomphus have have decurrent lamellae and basidiospore deposits that are type localities in Europe: C. britannicus A. Z. M. Khan & grey to black. The genus Chroogomphus has been further Hora 1978, C. corallinus O.K. Mill. & Watling 1970, C. divided into two sections: Chroogomphus, with a pileipellis fulmineus (R. Heim) Courtec. 1988, C. helveticus (Singer) of compressed gelatinised hyphae, and Floccigomphus M.M. Moser 1967, C. mediterraneus (Finschow) Vila et al. © 2018 International Mycological Association You are free to share - to copy, distribute and transmit the work, under the following conditions: Attribution: You must attribute the work in the manner specified by the author or licensor (but not in any way that suggests that they endorse you or your use of the work). Non-commercial: You may not use this work for commercial purposes. No derivative works: You may not alter, transform, or build upon this work. For any reuse or distribution, you must make clear to others the license terms of this work, which can be found at http://creativecommons.org/licenses/by-nc-nd/3.0/legalcode. Any of the above conditions can be waived if you get permission from the copyright holder. Nothing in this license impairs or restricts the author’s moral rights. VOLUME 9 · NO. 2 271 Scambler et al. 2006, and C. rutilus (Schaeff.) O.K. Mill. 1964. However, the Previous studies have reported that Chroogomphus is application of these names remains open to interpretation as associated with other suilloid fungi, namely Rhizopogon no type material has been sequenced to date. In addition, and Suillus, but is also able to form ectomycorrhizas with there are differing opinions regarding synonymy, as well species of Pinaceae (Agerer 1990). Similarly, when studying as uncertainties regarding the delimitation of taxa and the closely-related genus Gomphidius, Olsson et al. ARTICLE identification of specimens due to overlapping morphological (2000) concluded that G. roseus was a parasite on Suillus characters. There is, therefore, disagreement over the total bovinus, as opposed to, or possibly as well as, being an number of species of Chroogomphus thought to occur in ectomycorrhizal partner of conifers. The detailed resource Europe and in individual European countries. C. rutilus was relationships of Chroogomphus, and of Gomphidiaceae in considered to be the only European species by Miller (1964) general, remain unclear and lie beyond the scope of the and, more recently, Knudsen & Taylor (2012) regarded this current study. as the only species occurring in northern Europe. Similarly, it In this paper we aim to: (1) provide a clearer picture of is the only currently accepted species on the British and Irish the overall species diversity of Chroogomphus in Europe; (2) checklist (Legon & Henrici 2005). By contrast, from the latest typify C. rutilus in order to fix the application of this sanctioned molecular study by Martín et al. (2016) it can be inferred that name; and (3) provide an updated infrageneric classification. at least six species occur in Europe. Members of the genus Chroogomphus occur throughout the Northern Hemisphere, with only one species, C. papillatus, MATERIALS AND METHODS reported from the Southern Hemisphere (Raithelhuber 1974). It is notable that currently there is no molecular evidence of Morphological examination any of the species having a distribution encompassing both The following descriptions of macromorphological characters North America and Eurasia. Moreover, there do not appear to of the specimens studied were based on notes taken from be many species with an intercontinental distribution across fresh collections and associated photographs, with the both Europe and Asia (Miller & Aime 2001, Li et al. 2009, exception of C. britannicus whose description is based on the Martín et al. 2016); C. rutilus occurs in both Europe and Asia; protologue. The colour nomenclature in the description of C. and C. purpurascens, originally described from the former britannicus follows Ridgway (1912). A total of 43 specimens Soviet Union, is now known also to occur in Europe (Li et al. were examined, the majority of these were from RBG Kew’s 2009). collection (K), the Botanical Museum of the University of The most useful morphological characters for distinguish- Helsinki (H), the herbarium of the Faculty of Pharmacy, Lille ing similar species of Chroogomphus include: thickness of (LIP), the Mycological Collection of the Institute of Biodiversity the cystidial wall, width of hyphae in the pileipellis and spore and Ecosystem Research, Sofia (SOMF), and the private size. The gelatinization of hyphae in the pileipellis can also be fungarium of M. Loizides. a useful character, as can the colour of the mycelium at the Micromorphological characters were observed using light base of the stipe (Miller & Aime 2001, Li et al. 2009, Martín microscopy. Dried tissue fragments of lamellae, pileipellis, et al. 2016). stipe and basal mycelium were mounted in Melzer’s reagent Species of Chroogomphus are found in coniferous or a 10 % potassium hydroxide (KOH). Melzer’s reagent was forests dominated by Pinaceae. Miller described the genus used for all measurements and for testing the colour reactions as forming basidiomes under