Sidera, a new genus in Hymenochaetales with poroid and hydnoid species

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1 Mycol Progress (2011) 10: DOI /s ORIGINAL ARTICLE Sidera, a new genus in Hymenochaetales with poroid and hydnoid species Otto Miettinen & Karl-Henrik Larsson Received: 18 February 2010 /Revised: 4 May 2010 /Accepted: 10 May 2010 /Published online: 20 June 2010 # German Mycological Society and Springer 2010 Abstract A new genus, Sidera (Hymenochaetales), is described to accommodate the dimitic polypores Skeletocutis lenis and S. vulgaris, the monomitic polypore Ceriporiopsis lowei, and the monomitic, hydnoid Athelopsis lunata. The genus is characterised by white-rot, whitish resupinate fruiting bodies, crystal rosettes on specialised hyphae, and allantoid spores. Cinereomyces (Polyporales) is confirmed to be a good genus including C. lindbladii, separate from Diplomitoporus as defined by its type species D. flavescens and the closely related D. crustulinus. Fabisporus is a taxonomic synonym of Diplomitoporus. Poriodontia subvinosa belongs to the Hymenochaetales. Keywords Micromorphology. ITS. LSU. Taxonomy Introduction The generic placement of the polypore Physisporus lenis P. Karst has long been uncertain. The first combinations of the species as Amyloporia lenis (Bondartsev 1953) and Antrodia lenis (Ryvarden 1973) were in a sense quite Taxonomical novelties Sidera Miettinen & K.H. Karsson, Sidera lenis (P. Karst.) Miettinen, Sidera lowei (Rajchenb.) Miettinen, Sidera lunata (Romell ex Bourdot & Galzin) K.H. Larsson, Sidera vulgaris (Fr.: Fr.) Miettinen O. Miettinen (*) Botanical Museum, University of Helsinki, P.O. Box 7, University of Helsinki, Finland otto.miettinen@helsinki.fi K.-H. Larsson Natural History Museum, University of Oslo, P.O. Box 1172, Blindern, 0318 Oslo, Norway k.h.larsson@nhm.uio.no natural. Morphologically, the species would still fit rather well in those genera being dimitic, resupinate, acyanophilous and having no cystidia. However, once it was understood that type of rot was an important factor for generic placement, P. lenis as a white-rot fungus had to be removed. With regard to micromorphology, the most natural placement then was Diplomitoporus lenis, the white-rot counterpart of Antrodia (Gilbertson and Ryvarden 1985). By the 1990s, it had become clearer that polypores are not a natural group but a collection of morphologically and ecologically similar species (e.g. Donk 1964; Petersen 1971; Oberwinkler 1977; Parmasto 1986; Ryvarden 1991; Hibbett 2007). The same situation is replicated on a smaller scale in the concepts of certain polypore genera: for instance, Antrodiella, Ceriporiopsis and Diplomitoporus are in fact litter bags for species that share common macroscopic and microscopic characters, but are not necessarily related. Diplomitoporus has accommodated a variety of whiterot fungi with dimitic hyphal structure, middle-sized spores, and usually resupinate fruiting bodies. Niemelä sought to narrow down Diplomitoporus to include only species with slightly cyanophilous hyphae similar to those in D. flavescens (Bres.) Domanski, the type species of the genus. Consequently, he made the combination Skeletocutis lenis (Renvall et al. 1991). He emphasised that acyanophilous hyphae, star-like crystal aggregations and allantoid spores were characters that S. lenis shared with other Skeletocutis species. Yet, the type of encrustation (big rosettes vs thorns) and the loose hyphal structure do not exactly agree with those of other Skeletocutis species. Later, Niemelä (2005) accepted Cinereomyces (Jülich 1982) typified with C. lindbladii, and the new combination Cinereomyces lenis (Spirin 2005). C. lindbladii and C. lenis

2 132 Mycol Progress (2011) 10: share many characters: they are both resupinate white-rot fungi usually found on rotten logs, have acyanophilous hyphae and middle-sized allantoid spores. In this paper, we use molecular phylogenetic methods to test if any of the published hypotheses regarding the generic arrangement for Physisporus lenis can be verified.niemelä and Dai (1997) divided S. lenis into two species: a boreal, mostly pine-inhabiting old-growth forest species, S. lenis, and its southern, more generalist counterpart Skeletocutis vulgaris (Fr.) Niemelä & Y.C. Dai. While studying some southern specimens collected by Leif Ryvarden, one of us (O.M.) noticed similar crystal stars born on specialised hyphae as in S. vulgaris occurring in specimens of Ceriporiopsis lowei Rajchenb. In fact, when describing that species, Rajchenberg (1987) pointed to similarities between S. lenis and C. lowei. Thus, we included C. lowei in the analysis as well. Materials and methods Material studied We chose reference taxa for the phylogenetic analysis based on Ko and Jung (1999), Binder et al. (2005), Larsson et al. (2004, 2006), Larsson (2007a, b) and Tomšovský (2006, 2008), and through searches in GenBank. Eighteen new nrdna sequences were produced for this study (Table 1), while reference sequences of 58 taxa were obtained from GenBank (Table 2). When selecting species, the emphasis was on generic types. Specimens used for this study are listed below. DNA of specimens marked with asterisk (*) has been utilised in this study. Antrodiella pallescens (Pilát) Niemelä & Miettinen. Finland. Uusimaa, Hyvinkää, 26.IV.2008 Miettinen (H*). Cerrena unicolor (Bull.) Murrill. Finland. Kainuu, Suomussalmi, 30.IX.2004 Miettinen 9443 (H*). Cinereomyces lindbladii (Berk.) Jülich. Finland. Uusimaa, Inkoo, 24.V.2003 Kotiranta (H*). Helsinki, 17. VI.2008 Miettinen (H). Norway. Telemark, Sauherad, 24.IX.2003, K.H. Larsson (GB*). Diplomitoporus flavescens (Bres.) Domanski. Germany. Hessen, Rödermark, 7.III.1996 Sturm s.n. (H*). Norway. Finnmark, Karasjok, 31.VIII.2008 Miettinen (H). Diplomitoporus crustulinus (Bres.) Domanski. Finland. Sodankylän Lappi, Pelkosenniemi, 13.VIII.1998 Tuomo Niemelä 6293 & Terhi Hakala culture T56* (H). Gelatoporia subvermispora (Pilát) Niemelä. Russia. Perm, Kvarkush, 6.VIII.2005 Kotiranta (H*). Hyphoderma setigerum (Fr.) Donk. Sweden. Skåne, Simrishamn, 1.X.1984 Hallenberg 8544, culture FCUG 1264* (GB). Oxyporus populinus (Schumach.) Donk. Finland. Uusimaa, Espoo, 21.V.2006 Miettinen (H*). Poriodontia subvinosa Parmasto. China. Jilin, Antu, Changbai. 25.VIII.2005 Miettinen (H*). Schizopora paradoxa (Schrad.) Donk. Finland. Etelä- Häme, Kuru, IX.2003 Miettinen 7978 (H*) Sidera lenis (P. Karst.) Miettinen. Finland. Etelä-Häme (see type under combination). Pohjois-Savo, Heinävesi, 2. Table 1 List of specimens sequenced for this study Taxon Herbarium specimen Origin ITS ITS+LSU Antrodiella pallescens Miettinen Finland FN Cerrena unicolor Miettinen 9443 Finland FN Cinereomyces lindbladii NO KH Larsson Norway FN Cinereomyces lindbladii FI Kotiranta Finland FN Diplomitoporus crustulinus FI Niemelä 6293 Finland FN Diplomitoporus flavescens Sturm s.n. Germany FN Gelatoporia subvermispora Kotiranta Russia FN Hyphoderma setigerum Hallenberg 8544 Sweden FN Oxyporus populinus Miettinen Finland FN Poriodontia subvinosa Miettinen China FN Schizopora paradoxa Miettinen 7978 Finland FN Sidera lenis Miettinen Finland FN Sidera lowei NZ Ryvarden New Zealand FN Sidera lowei VE Ryvarden Venezuela FN Sidera vulgaris AU Gates FF257 Australia FN Sidera vulgaris NZ Ryvarden New Zealand FN Skeletocutis amorpha Miettinen Finland FN Skeletocutis chrysella Miettinen 9472 Finland FN907916

3 Mycol Progress (2011) 10: Table 2 List of taxa and nrdna sequences retrieved from GenBank with accession numbers Taxon ITS/5.8S LSU Antrodia albida DQ AY Basidioradulum radula AF AF Bjerkandera adusta DQ AF Byssomerulius corium AY AY Ceraceomyces violascens EU EU Ceriporia viridans AF AF Ceriporiopsis aneirina EU EU Coltricia perennis DQ AF Coltriciella dependens AM AM Contumyces rosella U66452 U66452 Diplomitoporus crustulinus AY Donkioporia expansa FJ FJ Exidiopsis calcea AY AY Fibricium rude AY Ganoderma adspersum AM AM Globulicium hiemale DQ DQ Gloeoporus dichrosus EU EU Gloeoporus pannocinctus AF AF Hymenochaete rubiginosa AY AY Hyphoderma capitatum DQ DQ Hyphoderma definitum DQ DQ Hyphoderma orphanellum DQ DQ Hyphoderma transiens DQ DQ Hyphodermella corrugata EU EU Hyphodontia crustosa DQ DQ Hyphodontia curvispora DQ DQ Hyphodontia pallidula DQ DQ Hyphodontia subalutacea DQ DQ Hypochnicium polonense EU EU Mensularia radiata AF AF Meruliopsis taxicola EU EU Merulius tremellosus AF AF Mycoacia pinicola DQ DQ Odonticium romellii DQ DQ Oxyporus corticola DQ DQ Peniophorella praetermissa DQ DQ Peniophorella tsugae DQ Phanerochaete sordida EU EU Phellopilus nigrolimitatus AY AF Phlebia georgica DQ DQ Repetobasidium conicum DQ DQ Resinicium bicolor AY AY Resinicium chiricahuaense DQ Resinicium friabile DQ DQ Resinicium furfuraceum DQ DQ Resinicium meridionalis AY Resinicium saccharicola DQ DQ Rickenella mellea U66438 U66438 Table 2 (continued) Taxon ITS/5.8S LSU Scopuloides hydnoides EU EU Sidera lunata DQ DQ Sistotrema brinkmannii AF AF Skvortzovia furfurella DQ DQ Sphaerobasidium minutum DQ DQ Steccherinum ochraceum EU EU Taiwanofungus camphoratus AY AY Trametes ochracea AY AY Trametopsis cervina AY Trichaptum abietinum AF AF X.2006 Miettinen (H*). Pohjois-Karjala, Lieksa, 8.-9.X.2003 Miettinen 7662 (H). Sidera lowei (Rajchenb.) Miettinen. New Zealand. Southland, 5.V.1997 Ryvarden (O, H*). Venezuela. Estado Amazonas, Yutajé, 12.VI.1997 Ryvarden (O). Sidera lunata (Romell ex Bourdot & Galzin) K.H. Larsson. Finland. Pohjois-Häme, Jyväskylä, 15.VII.2007 Miettinen (H). Keski-Pohjanmaa, Perho, 15.X.2004 Halme 265 (H). Norway. Akershus, Eidsvoll, Sandholtjernet, 26.VIII.1997 Stokland (O*, DQ873593). Sidera vulgaris (Fr.: Fr.) Miettinen. Australia. Tasmania, Huon Valley, 16.I.2007 Gates FF257 (H*). New Zealand. Rotorua, 5.IV.1995 Ryvarden (O, H*). Poland. Podlaskie woj., Hajnówka, 20.V.1996 Niemelä 5981 (H). Skeletocutis amorpha (Fr.) Kotl. & Pouzar. Finland. Pohjois-Savo, Heinävesi, 2.X.2006 Miettinen (H*). Skeletocutis chrysella Niemelä. Finland. Kainuu, Suomussalmi, 1.X.2004 Miettinen 9472 (H*). DNA and phylogenetic methods DNA was extracted from herbarium specimens. DNeasy plant mini kit (Qiagen, Hilden) was used for DNA extraction, following the manufacturer s recommendations. PCR reactions were carried out using Ready-To-Go PCR beads (Amersham Pharmacia Biotech, Uppsala) or Phusion High-Fidelity DNA Polymerase (Finnzymes). Primers used to amplify ITS region were ITS1F, ITS1, ITS4, ITS4B and LR21 (depending on specimen), and for partial LSU region LR0R and LR7 (Gardes and Bruns 1993; Hopple and Vilgalys 1999; White et al. 1990). Amplified products were purified using Qiaquick spin columns (Qiagen) or Geneclean Turbo kit (Qbiogene). Primers used for ITS sequencing were ITS1, ITS4 and LR22, and for LSU CTB6, LR5, LR3R, and LR7 (White et al. 1990; Hopple and Vilgalys 1999; bruns). Sequencing was done as described in Larsson and Larsson (2003) or by Macrogen (Korea). Sequences were

4 134 Mycol Progress (2011) 10: edited and assembled using ChromasPro 1.42 (Technelysium) or Sequencher 3.1 (Gene Codes, Ann Arbor). The gene regions in the phylogenetic analysis were nrdna ITS and partial 28S. Starting point of LSU and ending point of 5.8S were determined with ITS2 database and Hmmer (Eddy 1998; Koetschan et al. 2010). Sequences were aligned using MAFFT with strategy G-INS-i and Q-INS-i (Katoh et al. 2005; Katoh and Toh 2008) and adjusted manually using PhyDE (Müller et al. 2008). Out of 74 LSU-sequenced specimens, 6 lacked 5.8S, and another 7 had significantly (>100 bp) shorter LSU than others. The part of ITS-LSU region used in tree building comprised of 5.8S, about 900 bp of 28S from the start, and ca. 18 bp adjacent ITS2. After removing unalignable regions, 1,065 characters remained, of which 405 were variable and 294 parsimony informative. Genetic distances between ITS sequences were obtained by first aligning globally pair-wise using EMBOSS variant of Stretcher (Myers and Miller 1988) and then calculating percentage similarities of those pair-wise alignments with dnadist of Phylip package (Felsenstein 2005). Parsimony analyses were executed in PAUP 4.0b10 (Sinauer; David Swofford) under Windows XP. All transformations were considered unordered and equally weighted. Gaps were treated as missing data. Branches were collapsed if zero length was possible (pset collapse = minbrlen). Heuristic searches used 1,000 random taxon addition replicates and tree bisection-reconnection (TBR) branch swapping with other options using the program s default settings. Relative robustness of clades was estimated through BS analysis using PAUP. Settings used were 1,000 BS replicates with 10 random addition sequences per replicate, TBR branch swapping, and otherwise default settings. For a Bayesian inference of phylogeny, a Bayesian inference run was done with MrBayes (Ronquist and Huelsenbeck 2003) using eight chains and three runs in parallel, partition to 5.8S and 28S, GTR+I+G substitution model in both partitions, and temp= Topology was constrained so that Exidiopsis calcea (outgroup) and Sistotrema brinkmannii were forced together. The analysis was run for 10 million generations, sampling every 1,000 generations. Burnin was set to 3,000 trees. Otherwise default settings were used. When selecting substitution model, recommendations of MrModeltest 2.2 (Nylander 2004) were followed. The analysis was done running eight processors in parallel in CSC IT Center for Science ( Morphology During microscopic studies, the mountant media used were Cotton Blue (CB), Melzer s reagent (IKI) and 5% KOH. Measurements and drawings were made in CB. Entry CB+ means cyanophily, CB- acyanophily; IKI- neither amyloid nor dextrinoid reaction. Measurements were done using 1,000 magnification and phase contrast illumination (see Miettinen et al for further detail). Pores and aculei were measured by subjectively choosing as straight line of pores or aculei as possible and measuring how many fit per mm. Sketches were vectorised in CorelDRAW X3. Results The three runs of the Bayesian analysis converged reasonably well (average SD of split frequencies constantly <0.013). Parsimony analysis produced essentially similar results as Bayesian analysis. The strict consensus parsimony tree supported all results discussed below, though partly with low bootstrap support, differing from the Bayesian results only in some deeper (above genus level) nodes irrelevant to this paper. We show here only the results of the Bayesian analysis. Diplomitoporus flavescens and D. crustulinus (Bres.) Domanski are closely related based on their ITS region (94% similarity). The two share mostly resupinate fruiting bodies with ochraceous colours and rather large pores, same type of cyanophilous hyphal structure, and middle-sized spores. Thus, we conclude that D. crustulinus is a good member of Diplomitoporus sensu stricto, D. flavescens being the type species of the genus. It follows that Fabisporus (Zmitrovich 2001), typified with F. crustulinus, is a taxonomic synonym of Diplomitoporus. Our analysis shows that Diplomitoporus belongs to the Polyporales (Fig. 1). Inside Polyporales, it seems to belong to the residual polyporoid clade of Binder et al. (2005) or Meruliaceae of Larsson (2007b). Cinereomyces also belongs to the Polyporales, but is clearly separate from Diplomitoporus, and closely related to Gelatoporia subvermispora (Pilát) Niemelä. Binder et al. (2005) placed C. lindbladii in the base of core polyporoid clade; our results also place C. lindbladii in the vicinity of core polyporoid clade but not necessarily inside it. In our analysis it and G. subvermispora form a sister group of Skeletocutis, which Binder et al. (2005) placed outside core polyporoid clade. Skeletocutis lenis, S. vulgaris and Ceriporiopsis lowei form a monophyletic group in Hymenochaetales, in Rickenella clade (Larsson et al. 2006; Larsson 2007b). They are clearly neither closely related genetically nor morphologically to other polypore genera in Hymenochaetales such as Coltricia, Oxyporus, Phellinus, Poriodontia, Schizopora and Trichaptum. Instead, their closest relative is Athelopsis lunata, also known as Trechispora lunata. It is a minutely hydnoid, outwardly Trechispora-looking species whose generic placement has always been unclear. Together, they form a

5 Mycol Progress (2011) 10: Fig. 1 Consensus phylogram of the 21,003 trees retained in the Bayesian analysis of nrdna 5.8S and 28S. Numbers represent Bayesian posterior probabilities. Branch lengths reflect expected changes per site as indicated by the scale. Clade names follow Binder et al. (2005) and Larsson et al. (2006), family names Larsson (2007b), and order names Hibbett et al. (2007)

6 136 Mycol Progress (2011) 10: monophyletic, well-defined group with strong support in phylogenetic analysis, and as subsequent microscopic study showed share a number of distinctive characters. Inside Rickenella clade, which is paraphyletic in this analysis, they do not group together with any other species. Below, we describe a new genus to accommodate these four species, Athelopsis lunata, Ceriporiopsis lowei, Skeletocutis lenis and Skeletocutis vulgaris. Taxonomy Sidera Miettinen & K.H. Larsson, gen. nov. MB Basidioma lignicola, resupinatum, pallidum, hymenophorum poroideum vel hydnoideum, pori regulares, pori et aculei satis parvi (4 12 per mm). Systema hypharum monomiticum vel dimiticum, hyphae generatoriae fibulatae. Cystidiola praesentia, crystalla praesentia, rosularia vel sideralia. Sporae allantoideae, tenuitunicatae, parvae, minus quam 5 µm longae. Putrificatio ligni alba. Type species: Sidera lenis (P. Karst.) Miettinen (=Physisporus lenis P. Karst.) Etymology: sidera, derived from sidus, star in Latin, referring to the rosulate or star-like crystals that characterise the genus. Basidiocarp resupinate, annual to perennial, white to yellowish cream-coloured, in some species with pinkish hue, small- to middle-sized, mm thick. Consistency felty to soft, not very hard. Hymenophore with pores or spines (S. lunata). Pores regular, middle-sized to small (4 12 pores per mm), aculei less than 1 mm long (approximately 8 9 aculei per mm). Margin thinning out. Hyphal system monomitic or dimitic, homogenous throughout the basidiocarp. Skeletal hyphae relatively loosely arranged, straight and without branches, CB-, IKI-, below 4 µm in diameter. Generative hyphae narrow, under 3 µm in diameter, thin-walled, acyanophilous or slightly cyanophilous, clamps present. Rosette-like crystals usually abundant in subiculum and sometimes in trama, 3 10( 20) µm in diameter, also irregular rhomboidal plates may be present; crystals are most abundant in old basidiocarps and if rare should be sought in subiculum; in most species they are born on specialised, narrow and branching generative hyphae, though this character is not visible in the type species. Oily substance in some species abundant. Cystidia present as cystidioles (hyphidia, thin-walled cystidia) in hymenium, subulate and long-necked (polypores) to cylindrical and slightly capitate (S. lunata). Clearly capitate, naked, thin-walled hyphal ends present in some species in vegetative parts and hymenium; these capitate hyphal ends occasionally surrounded by a halo or vesicle with a very thin cell wall in the tube mouths. The crystal bearing hyphae, if arising from hymenium, may be interpreted as asterocystidia; these are only rarely found in some species in hymenium. Hymenium. Basidia ellipsoid, cylindrical or clavate, usually 12 µm long or less. Basidiospores allantoid, i.e. ventral side of spores concave, and curved often strongly, thin-walled, smooth, under 5 µm long, CB-, IKI-, often few and never abundant in specimens. Ecology and distribution. Lignicolous, causing whiterot. Found in North and South America, Eurasia, Africa, Australia, and New Zealand, in boreal, temperate and tropical climates. Sidera lenis (P. Karst.) Miettinen, comb. nov. Basionym: Physisporus lenis P. Karst., in Rabenhorst & Winter, Fungi Eur. Extraeur. 36 [=ser. 2, 16]: no (label), Type: Finland. Etelä-Häme, Tammela, Mustiala. IX.1886 P. Karsten (lectotype by Lowe 1956, H). MB Sidera lowei (Rajchenb.) Miettinen, comb. nov. Basionym: Ceriporiopsis lowei Rajchenb., Nord. J. Bot. 7: 564, MB Sidera lunata (Romell ex Bourdot & Galzin) K.H. Larsson, comb. nov. Basionym: Grandinia lunata Romell ex Bourdot & Galzin, Hymenomyc. France: 410, MB Sidera vulgaris (Fr.: Fr.) Miettinen, comb. nov. Basionym: Polyporus vulgaris Fr., Syst. Mycol. 1: 381, MB Discussion Renvall et al. (1991) and Niemelä and Dai (1997) provide excellent illustrations of S. lenis and S. vulgaris, and Rajchenberg (1987) a drawing of S. lowei. They show well the defining characters of the genus: rosette-like crystals, specialised crystal bearing hyphae (absent or difficult to find in S. lenis), allantoid spores, and cystidioles (Fig. 2). Hjortstam et al. (1988:1506) provide an illustration of S. lunata, though that misses some of the above-mentioned characters.

7 Mycol Progress (2011) 10: Fig. 2 Sidera lenis, lectotype, a spores, b hymenium and cystidioles. Sidera lowei, Ryvarden 38817, c spores, d hymenial cells, cystidioles and crystals. Sidera vulgaris, Niemelä 5981, e capitate hyphal ends and 'halocystidia' in tube mouths. Sidera vulgaris, Gates , f crystal-bearing hyphae. Sidera lunata, Miettinen 11746, g spores, h hymenial cells, i subicular hyphae and crystals. S. lunata, Halme 265, j a spore

8 138 Mycol Progress (2011) 10: Genetic analysis shows that at least six taxa belong to the genus. The identity of the type species, S. lenis, has been sorted out by Renvall et al. (1991), and Niemelä and Dai (1997). We have re-studied the lectotype designated by Lowe (1956:113). We confirm the conclusion of these authors that S. lenis is a common boreal old-growth pine species, represented in this DNA study by the Finnish specimen Miettinen (H; see list of specimens for further detail). While the identity of the type species is clear, more work is needed before the other poroid species can be clearly delimited. Here, we follow current convention and call all the other dimitic specimens S. vulgaris, and all monomitic poroid specimens S. lowei. Table 3 summarises morphological characters of the currently accepted Sidera species. The genus includes both strictly monomitic and clearly dimitic species. This is not a unique situation: Skeletocutis includes strictly monomitic and dimitic species [e.g. S. azorica (D.A. Reid) Jülich vs S. stellae (Pilát) Jean Keller], and so does Fibroporia [F. norrlandica (Berglund & Ryvarden) Niemelä vs F. gossypium (Speg.) Parmasto] to give a few examples. The genetic variation inside Sidera is large and, for instance, the alignment of the ITS region is difficult if not impossible even among Sidera polypores (pairwise percentage similarities vary between 77 and 88). The question then arises whether the monomitic poroid species (here represented by two species) should be separated to yet another genus. However, such a division based on miticity is not supported by the phylogenetic analysis, since a dimitic specimen of S. vulgaris groups together with the monomitic S. lowei (Fig. 1). We have not found any other morphological character that could differentiate the polypores from each other and justify the introduction of several genera. A similar question arises with regard to hymenophore, since hydnoid and poroid species are placed together in one genus (Fig. 3). Examples of genera that include hydnoid and poroid species include Trechispora [e.g. T. stevensonii (Berk. & Broome) K.H. Larsson vs T. hymenocystis (Berk. & Broome) K.H. Larsson] and Sistotrema [e.g. S. muscicola (Pers.) S. Lundell vs S. alboluteum (Bourdot & Galzin) Bondartsev & Singer]. According to the LSU-based analysis, S. lunata takes a basal position in Sidera (Fig. 1). It deviates clearly from other Sidera species with its hydnoid hymenophore, less cylindrical spores, a bit longer, often sinuous basidia, and cylindrical to slightly capitate cystidioles (Fig. 2). However, it does show the key microscopic characters of the genus: rosette-like crystals, specialised hyphae bearing them, presence of cystidioles or thin-walled hymenial cystidia, short curved spores, and narrow hyphae. Also, the growth habit on well-decayed (coniferous) wood and the white colour of the fruiting body are typical of Sidera. Thus, grounds for including S. lunata in Sidera are there. The other option would be to create another genus for this species alone, limiting Sidera to polypores. We wish to progress cautiously when creating new genera, particularly monotypic genera, and prefer to include S. lunata in the same, monophyletic genus with the polypores for now. In the phylogenetic analysis, relatives of Sidera within the Rickenella clade (Larsson et al. 2006; Larsson 2007b) include species of the heterogenous genus Resinicium. The rosette crystal-bearing hyphae found in S. lowei, S. lunata and S. vulgaris are quite similar to those present in Resinicium s. str. (see Eriksson et al. 1981:1266, and Nakasone 2007 for illustrations). Also, the capitate hyphal ends of S. vulgaris remind Resinicium halocystidia (Fig. 2e). Our LSU-based analysis does not support a close relationship between Sidera and any species of Resinicium included in the analysis. Resinicium does not form a monophyletic or even a paraphyletic group with Sidera. Resinicium bicolor (Alb. & Schwein.) Parmasto, the generic type, is not closely related to Sidera (Fig. 1). Further ITS-based comparison (not shown) indicates that none of the species of Resinicium s. str. (sensu Nakasone 2007) is particularly close either (similarities 75%). As Resinicium species are hydnoid and bear rosette crystals, they remind of Sidera lunata. Like in Sidera, hyphidia or cystidioles are also present in some Resinicium species. The type species, R. bicolor, is characterised by conspicuous halocystidia and asterocystidia, hyphal ends bearing rosette crystals in hymenium. Although neither of these characters is present in all Resinicium species, they characterise Resinicium sensu stricto as defined by Nakasone (2007). Table 3 Main characters of Sidera species. Pore and spore sizes partly from Rajchenberg (1987), Niemelä and Dai (1997) and Niemelä (2005) Species Hymenium Hyphal system Spores shape Spore size (µm) Sidera lenis Pores, 4 6/mm Dimitic Strongly curved Sidera lowei Pores, 6 8/mm Monomitic Moderately curved Sidera lunata Aculei, 8 9/mm Monomitic Short allantoid Sidera vulgaris Pores, 6 8/mm Dimitic Strongly curved

9 Mycol Progress (2011) 10: Fig. 3 Hymenophore of Sidera lenis, Miettinen 7331 (left) and Sidera lunata Miettinen (right) Niemelä and Dai (1997) report halocystidia in Sidera vulgaris some of the capitate hyphal ends in the tube mouths show a halo similar to cystidia of Resinicium furfuraceum (Bres.) Parmasto. Unlike in Resinicium, those hyphal ends are not found in the hymenium, do not stain in CB, and are exceedingly rare. Niemelä and Dai (1997) also report hymenial asterocystidia (as cystidioles) in S. vulgaris, but generally they are rare, less conspicuous and then often a b c Fig. 4 Comparison of tramal skeletal hyphae and crystals in a Sidera lenis, lectotype, b Cinereomyces lindbladii, Miettinen 12696, c Diplomitoporus flavescens, Miettinen 13395

10 140 Mycol Progress (2011) 10: associated with senescent hymenium. None of the other species in Sidera has asterocystidia or halocystidia. A further difference between Sidera and Resincium s. str. sensu Nakasone (2007) is spore shape: short, curved spores of Sidera are not found in Resinicium s. str. Until now, Sidera lunata has mostly been placed in Trechispora. Although very similar to the naked eye, S. lunata lacks ampullate septa, a key character in Trechispora, and was not accepted in Trechispora by Larsson (1992). Cystidioles, crystal-bearing hyphae, narrow hyphae and curved smooth spores are other deviating characters. S. lunata has also been included in Athelopsis, but it shares few characters with species in that genus. Hydnoid hymenophore, cystidioles, crystals and curved spores are among the separating characters. Morphologically closest genera to the dimitic species of Sidera among white-rot genera are Cinereomyces, Diplomitoporus and Skeletocutis, and for the monomitic poroid species Ceriporiopsis, Gelatoporia and Skeletocutis. Although it belongs to Polyporales (Fig. 1), Skeletocutis morphologically resembles Sidera: narrow acyanophilous skeletal hyphae, small allantoid spores, and many resupinate, whitish species with small pores. It differs from Sidera mainly in the nature of its encrustation: in Skeletocutis, the crystals are like rose-thorns (Keller 1979), and seated on generative hyphae, usually on the tube mouths. The crystals in Sidera are faceted, much more robust and not restricted to tube mouths. In addition, typical members of Skeletocutis, including the type species S. amorpha (Fr.) Kotl. & Pouzar, have a rather dense hyphal structure in the trama that looks different from the subiculum; in Sidera, the hyphal structure is looser and uniform in trama and subiculum (for illustrations of Skeletocutis, see David 1982 and Niemelä 1998). Skeletocutis also includes several species with monomitic hyphal structure. Many of those species do not have allantoid spores, but all have rose-thorn-like encrustation on their hyphae and no rosette-like crystal clusters. Cinereomyces lindbladii, the only species of its genus, strongly resembles Sidera lenis, so much so that they can be mixed up in the field. Under the microscope, the clearest difference is in the skeletal hyphae: these have a very distinct lumen covering at least half of the hyphal width in Cinereomyces, and hyphae are rather irregular in outline. The hyphae are also much wider, commonly over 5 µm in diameter as opposed to under 3 4 µm in dimitic Sidera species. They also dissolve in KOH unlike those of Sidera species. Spores of C. lindbladii are on average only slightly curved and a bit larger than in any species of Sidera. Large crystals are found in trama, part of them in the shape of irregular rosettes (Fig. 4). Diplomitoporus represented by D. flavescens and D. crustulinus have corky hard, half-resupinate to resupinate basidiocarps, and cyanophilous skeletal hyphae with a distinct but rather narrow lumen. The hyphae are also wider than in Sidera, commonly over 4 µm in diameter. No crystals are usually found in the trama. Spores are clearly larger in all respects, and so are hymenial cells, over 15 µm long. In comparison to Cinereomyces, skeletals are more regular, have narrower lumen, are cyanophilous (as opposed to CB- in Cinereomyces), and hymenial cells are consistently larger (Fig. 3). We currently accept Gelatoporia subvermispora as the only species in its genus. Sidera lowei and G. subvermispora share a monomitic hyphal structure, allantoid spores, and crystals on hyphae. Both are also white-rot fungi. When Rajchenberg (1987) described Ceriporiopsis lowei, he in fact based his Latin protologue on that species ( A Poria subvermispora Pilát differt poris minoribus 6 8 per mm et cystidiolis fusiformibus ). Gelatoporia differs from Sidera in the nature of its crystals, which are never rosette-like in G. subvermispora but grain-like and attached to hyphal walls (see Niemelä 1985:30 for an excellent illustration). Furthermore, Gelatoporia has slightly thick-walled generative hyphae that agglutinate to a dense structure, whereas all species of Sidera have a relatively loose hyphal structure with thin-walled generative hyphae. As Rajchenberg states, cystidioles are not found in Gelatoporia. The type species of Ceriporiopsis, C. gilvescens (Bres.) Domanski and the type species of Raduliporus, C. aneirina (Sommerf.) Domanski, have monomitic hyphal structure with clamps, but also thick-walled hyphae, ellipsoid spores and lack characteristic encrustation. Sidera lenis has been combined in Antrodiella (Zmitrovich 2003). Fruiting bodies of Antrodiella species are tough when dry and never soft or felty as in Sidera. Skeletal hyphae are slightly cyanophilous and rather densely arranged. Encrustation is present as irregular rhomboidal plates or crystal clumps, if at all. Most Antrodiella species have ellipsoid spores and none as curved as in Sidera. Furthermore, Antrodiella belongs to the Polyporales (Fig. 1). Acknowledgements We thank Teuvo Ahti (Helsinki) for revising the nomenclature and Latin, and Tuomo Niemelä (Helsinki) for commenting the manuscript. Material provided by Leif Ryvarden (Oslo) greatly enhanced this study. Genevieve Gates (Tasmania) provided also valuable specimens. 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