Research Article |
Corresponding author: Karl-Henrik Larsson ( k.h.larsson@nhm.uio.no ) Academic editor: María P. Martín
© 2019 Karl-Henrik Larsson, Sten Svantesson, Diana Miscevic, Urmas Kõljalg, Ellen Larsson.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Larsson K-H, Svantesson S, Miscevic D, Kõljalg U, Larsson E (2019) Reassessment of the generic limits for Hydnellum and Sarcodon (Thelephorales, Basidiomycota). MycoKeys 54: 31-47. https://doi.org/10.3897/mycokeys.54.35386
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DNA sequences from the nuclear LSU and ITS regions were used for phylogenetic analyses of Thelephorales with a focus on the stipitate hydnoid genera Hydnellum and Sarcodon. Analyses showed that Hydnellum and Sarcodon are distinct genera but that the current division, based on basidioma texture, makes Sarcodon paraphyletic with respect to Hydnellum. In order to make genera monophyletic several species are moved from Sarcodon to Hydnellum and the following new combinations are made: Hydnellum amygdaliolens, H. fennicum, H. fuligineoviolaceum, H. fuscoindicum, H. glaucopus, H. joeides, H. lepidum, H. lundellii, H. martioflavum, H. scabrosum, H. underwoodii, and H. versipelle. Basidiospore size seems to separate the genera in most cases. Hydnellum species have basidiospore lengths in the range 4.45−6.95 µm while the corresponding range for Sarcodon is 7.4−9 µm. S. quercinofibulatus deviates from this pattern with an average spore length around 6 µm. Neotropical Sarcodon species represent a separate evolutionary lineage.
Phylogeny, stipitate hydnoid, taxonomy, Thelephorales, tooth fungi
The order Thelephorales is a distinctive lineage of Agaricomycetes, well-known for its almost ubiquitous ectomycorrhizal life style (
In a recent comprehensive study of stipitate hydnoid species from south-eastern North America,
In this paper we analyse ITS and nuclear LSU sequences from a wide selection of Thelephorales species with a focus on Hydnellum and Sarcodon in order to resolve the relationship between these two genera. We also make some nomenclatural changes that follow from the revision of genus circumscriptions. We demonstrate that Neotropical Sarcodon species do not cluster with temperate and boreal species and may be warranted as one or more new genera with more data.
For the phylogenetic analyses we compiled two datasets. The first dataset consists of nuclear LSU sequences from most genera in Thelephorales and from a majority of the Hydnellum and Sarcodon species occurring in Europe. For our two target genera we chose only sequences generated for this study from recently collected basidiomata. We deliberately excluded sequences from specimens identified as H. concrescens or H. scrobiculatum since these names seem to cover more than just two species and it is currently unclear how the names should be applied (
For our second dataset we chose a different strategy. Here we included ITS sequences from all Hydnellum and Sarcodon species represented among our own sequences and in GenBank as of December 1, 2018. The reason is that many species, and especially the recently described species from tropical regions, are only available as ITS sequences. However, we made no attempt to verify the identifications given in GenBank and do not endorse them as correct.
DNA was extracted from recent dried collections of basidiomata from North Europe. Voucher numbers, herbarium location, and GenBank numbers are given in Table
Specimens sequenced or downloaded from GenBank. Herbarium acronyms follow Thiers. Sequences generated for this study are marked in bold.
Species | Voucher | Herb. | GenBank number | |
---|---|---|---|---|
ITS | LSU | |||
Amaurodon aquicoeruleus Agerer | Agerer & Bougher | M | AM490944 | AM490944 |
Amaurodon viridis (Alb. & Schwein.:Fr.) J.Schröt | KH Larsson 14947b | O | MK602707 | MK602707 |
Bankera fuligineoalba (J.C.Schmidt:Fr.) Pouzar | E Larsson 400-13 | GB | MK602708 | MK602708 |
Bankera violascens (Alb. & Schwein.:Fr.) Pouzar | MV 130902 | GB | MK602709 | MK602709 |
Boletopsis leucomelaena (Pers.:Fr.) Fayod | M Krikorev 140912 | GB | MK602710 | MK602710 |
Hydnellum aurantiacum (Batsch:Fr.) P.Karst. | RG Carlsson 08-105 | GB | MK602711 | MK602711 |
Hydnellum aurantiacum | E Bendiksen 177-07 | O | MK602712 | MK602712 |
Hydnellum aurantiacum | O-F-295029 | O | MK602713 | MK602713 |
Hydnellum auratile (Britzelm.) Maas Geest. | O-F-294095 | O | MK602714 | MK602714 |
Hydnellum auratile | O-F-242763 | O | MK602715 | MK602715 |
Hydnellum auratile | J Nitare 110926 | GB | MK602716 | MK602716 |
Hydnellum caeruleum (Hornem.:Fr.) P.Karst. | O-F-291490 | O | MK602717 | MK602717 |
Hydnellum caeruleum | E Bendiksen 575-11 | O | MK602718 | MK602718 |
Hydnellum caeruleum | E Bendiksen 584-11 | O | MK602719 | MK602719 |
Hydnellum complicatum Banker | REB 71 | KC571711 | ||
Hydnellum concrescens (Pers.) Banker | K(M)134463 | K | EU784267 | |
Hydnellum cristatum (G.F.Atk.) Stalpers | REB 169 | TENN | JN135174 | |
Hydnellum cumulatum K.A.Harrison | SE Westmoreland 69 | AY569026 | ||
Hydnellum cyanopodium K.A.Harrison | SE Westmoreland 85 | AY569027 | ||
Hydnellum diabolus Banker | KAH 13873 | MICH | AF351863 | |
Hydnellum dianthifolium Loizides, Arnolds & P.-A.Moreau | ML61211HY | KX619419 | ||
Hydnellum earlianum Banker | REB 375 | TENN | JN135179 | |
Hydnellum ferrugineum (Fr.:Fr.) P.Karst. | O-F-297319 | O | MK602720 | MK602720 |
Hydnellum ferrugineum | E Larsson 356-16 | GB | MK602721 | MK602721 |
Hydnellum ferrugineum | E Larsson 197-14 | GB | MK602722 | MK602722 |
Hydnellum ferrugipes Coker | REB 176 | KC571727 | ||
Hydnellum geogenium (Fr.) Banker | O-F-66379 | O | MK602723 | MK602723 |
Hydnellum geogenium | O-F-296213 | O | MK602724 | MK602724 |
Hydnellum geogenium | E Bendiksen 526-11 | O | MK602725 | MK602725 |
Hydnellum gracilipes (P.Karst.) P.Karst. | E Larsson 219-11 | GB | MK602726 | MK602726 |
Hydnellum gracilipes | GB-0113779 | GB | MK602727 | MK602727 |
Hydnellum mirabile (Fr.) P.Karst. | RG Carlsson 11-119 | GB | MK602728 | MK602728 |
Hydnellum mirabile | E Larsson 170-14 | GB | MK602729 | MK602729 |
Hydnellum mirabile | S Lund 140912 | GB | MK602730 | MK602730 |
Hydnellum peckii Banker | S Svantesson 328 | GB | MK602731 | MK602731 |
Hydnellum peckii | E Larsson 174-14 | GB | MK602732 | MK602732 |
Hydnellum peckii | E Bendiksen 567-11 | O | MK602733 | MK602733 |
Hydnellum pineticola K.A.Harrison | RB 94 | KC571734 | ||
Hydnellum piperatum Maas Geest. | REB 322 | TENN | JN135173 | |
Hydnellum regium K.A.Harrison | SE Westmoreland 93 | AY569031 | ||
Hydnellum scleropodium K.A.Harrison | REB 3 | TENN | JN135186 | |
Hydnellum scrobiculatum (Fr.) P.Karst. | REB 78 | TENN | JN135181 | |
Hydnellum spongiosipes (Peck) Pouzar | REB 52 | TENN | JN135184 | |
Hydnellum suaveolens (Scop.:Fr.) P.Karst. | E Larsson 139-09 | GB | MK602734 | MK602734 |
Hydnellum suaveolens | E Larsson 8-14 | GB | MK602735 | MK602735 |
Hydnellum suaveolens | S Svantesson 877 | GB | MK602736 | MK602736 |
Hydnellum subsuccosum K.A.Harrison | REB 10 | TENN | JN135178 | |
Lenzitopsis daii L.W.Zhou & Kõljalg | Yuan 2959 | IFP | JN169799 | JN169793 |
Lenzitopsis oxycedri Malençon & Bertault | KH Larsson 15304 | GB | MK602774 | MK602774 |
Odontia fibrosa (Berk. & M.A.Curtis) Kõljalg | TU115028 | TU | MK602775 | MK602775 |
Phellodon cf niger | E Larsson 35-14 | GB | MK602782 | MK602782 |
Phellodon tomentosus (L.:Fr.) Banker | E Bendiksen 118-10 | O | MK602781 | MK602781 |
Pseudotomentella flavovirens (Höhn. & Litsch.) Svrček | KH Larsson 16190 | O | MK602780 | MK602780 |
Sarcodon amygdaliolens Rubio Casas, Rubio Roldán & Català | SC 2011 | JN376763 | ||
Sarcodon aspratus (Berk.) S.Ito | DQ448877 | |||
Sarcodon atroviridis (Morgan) Banker | REB 104 | TENN | JN135190 | |
Sarcodon atroviridis | REB 61 | KC571768 | ||
Sarcodon bairdii A.C.Grupe & Vasco-Pal. | Vasco 990 | HUA | KR698938 | |
Sarcodon colombiensis A.C.Grupe & Vasco-Pal. | Vasco 2084 | HUA | KP972654 | |
Sarcodon fennicus (P.Karst.) P.Karst. | S Westerberg 110909 | GB | MK602739 | MK602739 |
Sarcodon fennicus | O-F-242833 | O | MK602738 | MK602738 |
Sarcodon fennicus | O-F-204087 | O | MK602737 | MK602737 |
Sarcodon fuligineoviolaceus (Kalchbr.) Pat. | LA 120818 | GB | MK602740 | MK602740 |
Sarcodon fuligineoviolaceus | B Nylén 130918 | GB | MK602741 | MK602741 |
Sarcodon fuligineoviolaceus | A Molia 160-2011 | O | MK602742 | MK602742 |
Sarcodon fuscoindicus (K.A.Harrison) Maas Geest. | OSC 113622 | OSC | EU669228 | |
Sarcodon glaucopus Maas Geest. & Nannf. | RG Carlsson 13-060 | GB | MK602743 | MK602743 |
Sarcodon glaucopus | J Nitare 060916 | GB | MK602744 | MK602744 |
Sarcodon glaucopus | Å Edvinson 110926 | GB | MK602745 | MK602745 |
Sarcodon imbricatus (L.:Fr.) P.Karst. | S Svantesson 355 | GB | MK602748 | MK602748 |
Sarcodon imbricatus | J Rova 140829-2 | GB | MK602746 | MK602746 |
Sarcodon imbricatus | E Larsson 384-10 | GB | MK602747 | MK602747 |
Sarcodon joeides (Pass.) Bataille | RG Carlsson 11-090 | GB | MK602749 | MK602749 |
Sarcodon joeides | K Hjortstam 17589 | GB | MK602750 | MK602750 |
Sarcodon joeides | J Nitare 110829 | GB | MK602751 | MK602751 |
Sarcodon joeides | REB 270 | KC571772 | ||
Sarcodon lepidus Maas Geest. | E Grundel 110916 | GB | MK602753 | MK602753 |
Sarcodon lepidus | RG Carlsson 10-065 | GB | MK602752 | MK602752 |
Sarcodon lepidus | J Nitare 110829 | GB | MK602754 | MK602754 |
Sarcodon leucopus (Pers.) Maas Geest. & Nannf. | O-F-296944 | O | MK602756 | MK602756 |
Sarcodon leucopus | O-F-296099 | O | MK602755 | MK602755 |
Sarcodon leucopus | P Hedberg 080811 | GB | MK602757 | MK602757 |
Sarcodon lundellii Maas Geest. & Nannf. | L&A Stridvall 06-049 | GB | MK602758 | MK602758 |
Sarcodon lundellii | O-F-242639 | O | MK602759 | MK602759 |
Sarcodon lundellii | O-F-295814 | O | MK602760 | MK602760 |
Sarcodon martioflavus (Snell, K.A.Harrison & H.A.C.Jacks.) Maas Geest. | A Delin 110804 | GB | MK602763 | MK602763 |
Sarcodon martioflavus | O-F-242435 | O | MK602762 | MK602762 |
Sarcodon martioflavus | O-F-242872 | O | MK602761 | MK602761 |
Sarcodon pakaraimensis A.C.Grupe & T.W.Henkel | T Henkel 9554 | BRG | KM668103 | |
Sarcodon pallidogriseus A.C.Grupe & Vasco-Pal. | Vasco 989 | HUA | KR698939 | |
Sarcodon portoricensis A.C.Grupe & T.J.Baroni | TG Baroni 8776 | NY | KM668100 | |
Sarcodon quercophilus A.C.Grupe & Lodge | CFMR-BZ-3833 | NY | KM668101 | |
Sarcodon quercinofibulatus Pérez-De-Greg., Macau & J.Carbó | JC 20090718-2 | JX271818 | MK602773 | |
Sarcodon rufobrunneus A.C.Grupe & Vasco-Pal. | Vasco 1989 | HUA | KR698937 | |
Sarcodon scabripes (Peck.) Banker | REB 351 | TENN | JN135191 | |
Sarcodon scabrosus (Fr.) P.Karst. | O-F-295824 | O | MK602764 | MK602764 |
Sarcodon scabrosus | O-F-292320 | O | MK602766 | MK602766 |
Sarcodon scabrosus | O-F-360777 | O | MK602765 | MK602765 |
Sarcodon squamosus (Schaeff.) Quél. | O-F-177452 | O | MK602768 | MK602768 |
Sarcodon squamosus | E Larsson 248-12 | GB | MK602767 | MK602767 |
Sarcodon squamosus | O-F-295554 | O | MK602769 | MK602769 |
Sarcodon umbilicatus A.C.Grupe, T.J.Baroni & Lodge | TJ Baroni 10201 | NY | KM668102 | |
Sarcodon underwoodii Banker | REB 50 | KC571781 | ||
Sarcodon versipellis (Fr.) Nikol. | RG Carlsson 13-057 | GB | MK602771 | MK602771 |
Sarcodon versipellis | RG Carlsson 11-085 | GB | MK602772 | MK602772 |
Sarcodon versipellis | E Bendiksen 164-07 | O | MK602770 | MK602770 |
Sistotrema brinkmannii (Bres.) J.Erikss. | KH Larsson 14078 | GB | KF218967 | KF218967 |
Steccherinum ochraceum (J.F.Gmel.:Fr.) Gray | KH Larsson 11902 | GB | JQ031130 | JQ031130 |
Thelephora caryophyllea (Schaeff.:Fr.) Pers. | E Larsson 89-09S | GB | MK602776 | MK602776 |
Thelephora terrestris Ehrh.:Fr. | E Larsson 295-13 | GB | MK602777 | MK602777 |
Tomentella stuposa (Link) Stalpers | Th-0764 | O | MK602778 | MK602778 |
Tomentellopsis pulchella Kõljalg & Bernicchia | KH Larsson 16366 | O | MK602779 | MK602779 |
In the phylogenetic analyses we assumed the following minimal partitions for the nrDNA region: ITS1, 5.8S, ITS2 and LSU (approximately 1200 bases of the 5’ end). Two datasets were analysed separately: an LSU dataset only including the LSU region, and an ITS dataset including ITS1, 5.8S and ITS2. We used the automated best-fit tests implemented in PAUP* 4.0a (
To generate Bayesian phylogenetic trees (BI) from the alignments we used BEAST 2.4.7 (
To generate Maximum Likelihood (ML) gene trees we used PHYML 3.1 (
Seventy-five Thelephorales specimens from the genera Amaurodon, Bankera, Boletopsis, Hydnellum, Lenzitopsis, Phellodon, Pseudotomentella, Sarcodon, Thelephora, Tomentella, and Tomentellopsis, were sequenced for this study. In addition, 39 sequences were downloaded from public databases (GenBank, UNITE) including outgroup sequences of Steccherinum ochraceum (Polyporales) and Sistotrema brinkmannii (Cantharellales) included in the LSU dataset. The ITS analyses were rooted by the default method (BEAST) or left unrooted (PHYML).
The aligned LSU dataset consisted of 1443 nucleotide positions. After exclusion of ambiguous regions 1377 positions remained for the analyses. BI returned a tree where the focus genera Hydnellum and Sarcodon are distributed over two strongly supported clades. The larger of these clades includes the type of Hydnellum, H. suaveolens, and an additional 17 species, all except one forming strongly supported terminal clades. Nine of these taxa are currently placed in Sarcodon. With a few exceptions the relationships within Hydnellum are not resolved. H. aurantiacum and H. auratile are recovered as a strongly supported group; Sarcodon scabrosus and S. fennicus are grouped with 0.97 posterior probability support; S. fuligineoviolaceus, S. glaucopus, and S. joeides form a subclade with 0.97 posterior probability support; and finally H. suaveolens and S. versipellis form a strongly supported clade. The type of Sarcodon, S. imbricatus, and three other species form the second main clade. The three sequences of S. imbricatus cluster together but the clade is unsupported. Hydnellum and Sarcodon are recovered as sister clades but the support for this arrangement is weak.
For target taxa the ML tree is essentially similar to the BI tree with strong support for the similarly composed Hydnellum and Sarcodon clades (Fig.
The aligned ITS dataset consisted of 1068 nucleotide positions of which 505 remained for the analyses after removal of ambiguous regions. Bayesian inference produced a tree with two strongly supported clades (Fig.
Maximum likelihood analyses of LSU dataset for Thelephorales. Branches in bold have a posterior probability value of 1 in Bayesian inference and 100% bootstrap support in ML analysis, if not otherwise indicated by a figure. Lower support values on other branches are indicated by figures. Steccherinum ochraceum and Sistotrema brinkmannii are used as outgroup (branch lengths shortened).
The ML tree recovered the same two main clades with strong support but could not resolve the relationships within the larger Hydnellum/Sarcodon clade. In the ML tree the clade corresponding to Hydnellum in the LSU tree is correctly identified but not supported while the clade corresponding to Sarcodon appears polyphyletic.
Based on these results we hereby revise the limits of the two genera by moving a number of species from Sarcodon to Hydnellum. Consequently the genus description for Hydnellum must be emended while the genus description for Sarcodon can remain unaltered.
Hydnellum suaveolens (Scop.:Fr.) P.Karst. (1879)
Hydnum suaveolens Scop.:Fr. (1772)
Basidiomata with pileus and stipe, single or concrescent; pileus thin to thick, at first smooth and velutinous, when mature felted, fibrillose, scaly, ridged, or irregularly pitted and scrupose, mostly brownish but also with white, olive yellowish, orange, purplish or bluish colours, often concentrically zonate; stipe narrow to thick, solid, mostly short; hymenophore hydnoid, usually strongly decurrent; context from soft and brittle to corky or woody; hyphal system monomitic, septa with or without clamps, context hyphae inflated or not; cystidia lacking; basidia narrowly clavate, producing four sterigmata; basidiospores with irregular outline, more or less lobed, verrucose, brownish. Terrestrial, forming ectomycorrhiza with forest trees.
Sarcodon amygdaliolens Rubio Casas, Rubio Roldán & Català, Boln Soc. Micol. Madrid 35: 44−45. 2011. Holotype: Spain, Tamajón, Barranco la Jara. L. Rubio-Casas & L. Rubio-Roldán, AH 42113.
Sarcodon scabrosus var. fennicus P.Karst., Bidr. Känn. Finl. Nat. Folk 37: 104. 1882. Type: not indicated (neotype: H, designated by Maas Geesteranus & Nannfeldt 1969: 406)
Hydnum fuligineoviolaceum Kalchbr., in Fries, Hymenomyc. eur. (Upsaliae): 602. 1874. Holotype: Slovakia, Presovsky kraj, Olaszi. C. Kalchbrenner, UPS F-173546.
Hydnum fuscoindicum K.A.Harrison, Can. J. Bot. 42: 1213. 1964. Holotype: USA, Washington, Olympic Nat. Park, A.H. Smith. MICH 10847.
Sarcodon glaucopus Maas Geest. & Nannf., Svensk bot. Tidskr. 63: 407. 1969. Holotype: Sweden, Uppland, Börje par., J. Eriksson. UPS F-013955.
Hydnum joeides Pass., Nuovo G. bot. ital. 4: 157. 1872. Holotype: Italy, Emilia-Romagna, Collecchio, G. Passerini. PAD.
Sarcodon lepidus Maas Geest., Verh. K. ned. Akad. Wet., tweede sect. 65: 105. 1975. Holotype: The Netherlands, Lochem, Ampsen, G. & H. Piepenbroek. L.
Sarcodon lundellii Maas Geest. & Nannf., Svensk bot. Tidskr. 63: 421. 1969. Type: Sweden, Uppland, Storvreta, S. Lundell & J.A. Nannfeldt, distributed in S. Lundell & J.A. Nannfeldt Fungi exs. suec. as number 252 (lectotype, designated here, UPS F-010975; MycoBank No.: MBT387081). The UPS herbarium has two copies of the exsiccate and the specimens of H. lundellii are registered as F-010975 and F-013956, respectively. From F-010975 an ITS2 sequence has been generated [GenBank MK753037] and this specimen is here selected as lectotype).
Hydnum martioflavum Snell, K.A.Harrison & H.A.C.Jacks., Lloydia 25: 161. 1962. Holotype: Canada, Quebec, Ste Anne de la Pocatière, H.A.C. Jackson & W.H. Snell 13 Sep. 1954, BPI 259438.
Hydnum scabrosum Fr., Anteckn. Sver. Ätl. Svamp.: 62. 1836. Type: not indicated (neotype: Sweden, Småland, Femsjö, S. Lundell, UPS F-013954, designated by Maas Geesteranus & Nannfeldt 1969: 426)
Sarcodon underwoodii Banker, Mem. Torrey bot. Club 12: 147. 1906. Holotype: USA, Connecticut, NY 776131.
Hydnum versipelle Fr., Öfvers. K. Svensk. Vetensk.-Akad. Förhandl. 18(1): 31. 1861. Type: not indicated (neotype: Sweden, Uppland, Danmark par., J. Eriksson & H. Nilsson, UPS F-013958, designated by Maas Geesteranus & Nannfeldt 1969: 430)
Sarcodon imbricatus (L.:Fr.) P.Karst. (1881)
Hydnum imbricatum L.:Fr. (1753).
Basidiomata with pileus and stipe, single or concrescent; pileus thin to thick, at first smooth and velutinous, when mature smooth or scaly, brownish; stipe thick, solid, mostly short; hymenophore hydnoid, usually strongly decurrent; context soft and brittle; hyphal system monomitic, septa with clamps, context hyphae inflated; cystidia lacking; basidia narrowly clavate, producing four sterigmata; basidiospores with irregular outline, more or less lobed, verrucose, brownish. Terrestrial, forming ectomycorrhiza with forest trees.
In this paper we show that the current morphology-based concepts of Sarcodon and Hydnellum do not correspond to monophyletic subgroups within the Thelephorales. The characters traditionally used to separate the two genera do not reflect true relationships. These characters, however, are vague and open to subjectivity; hence it is not surprising that they have now been shown to be unreliable.
Instead of context structure it seems that average basidiospore size may in most cases offer a possibility to separate a Sarcodon species from one belonging to Hydnellum. Table
Basidiospore measurements for Hydnellum and Sarcodon from the literature. Sources: B =
Species | Measurements | Mean length |
Hydnellum aurantiacum (M) | (5.8−)6−6.7 × (4−)4.3−4.9 | 6.35 |
Hydnellum auratile (M) | 4.9−5.8 × 3.6−4.5 | 5.35 |
Hydnellum caeruleum (M) | 5.4−6(−6.3) × 3.4−4.3 | 5.70 |
Hydnellum compactum (Pers.:Fr.) P.Karst. (M) | 5.4−6.3 × 3.6−4.5 | 5.85 |
Hydnellum complicatum (B) | 4−5 × 3−5 | 4.50 |
Hydnellum concrescens (M) | 5.4−6.1 × (3.6−)4−4.5 | 5.75 |
Hydnellum cristatum (B) | 5−6 × 4−5 | 5.50 |
Hydnellum cruentum K.A.Harrison (B) | 4−5 × 3−4 | 4.50 |
Hydnellum cumulatum (M) | 4.3−5.6 × 3.6−4.3 | 4,95 |
Hydnellum diabolus (B) | 6−7 × 5−6 | 6.50 |
Hydnellum earlianum (B) | 5−6 × 4−5 | 5.50 |
Hydnellum fennicum (M) | 6.3−7.6 × 4.5−5.2 | 6.95 |
Hydnellum ferrugineum (M) | (5.4−)5.8−6.3 × 3.6−4.5 | 6.05 |
Hydnellum ferrugipes (B) | 5−7 × 5−6 | 6.00 |
Hydnellum fuligineoviolaceum (M) | 5.4−6.5 × 4−4.7(−5.4) | 5.95 |
Hydnellum geogenium (M) | 4.5−5.2 × 3.1−3.6 | 4.85 |
Hydnellum glaucopus (M) | (5−)5.4−5.8(−6.3) × (3.6−)4−4.5 | 5.60 |
Hydnellum gracilipes (M) | 4.3−4.6 × 2.7−3.6 | 4.45 |
Hydnellum joeides (M) | 5.4−5.8 × 3.6−4.2 | 5.60 |
Hydnellum lepidum (M) | 5.8−6.3 × 3.6−4.3 | 6.05 |
Hydnellum lundellii (M) | 4.9−5.8 × 3.6−4.2 | 5.35 |
Hydnellum martioflavum (M) | 5−6.3 × 3.6−4.5 | 5.65 |
Hydnellum peckii (M) | 4.9−5.4 × 3.8−4 | 5.15 |
Hydnellum pineticola (B) | 5−7 × 4−6 | 6.00 |
Hydnellum piperatum (B) | 4−6 × 4−5 | 5.00 |
Hydnellum scabrosum (M) | (5.4−)6.3−7.3 × (3.6−)4−5 | 6.80 |
Hydnellum scleropodium (B) | 4−6 × 3−4 | 5.00 |
Hydnellum spongiosipes (B) | 6−7 × 5−6 | 6.50 |
Hydnellum suaveolens (M) | 4−5 × 3−3.6 | 4.50 |
Hydnellum subsuccosum (B) | 5−6 × 4−6 | 5.50 |
Hydnellum versipelle (M) | 4.5−5.5 × 3.5−4.5 | 5.00 |
Hydnellum underwoodii (B) | 5−7 × 5−6 | 6.00 |
Sarcodon atroviridis (B) | 8−9 × 7−8 | 8.50 |
Sarcodon excentricus R.E.Baird (B) | 8−9 × 6−8 | 8.50 |
Sarcodon harrisonii R.E.Baird (B) | 7−9 × 6−8 | 8.00 |
Sarcodon leucopus (M) | (6.7−)7.2−7.6(−9) × 4.5−5.6 | 7.40 |
Sarcodon imbricatus (M) | 7.2−8.2 × 4.9−5.4 | 7.70 |
Sarcodon scabripes (B) | 8−10 × 7−9 | 9.00 |
Sarcodon squamosus (J) | 7.2−8.2 × 4.9−5.4 | 7.70 |
Not all sequences from species described as Sarcodon spp. were recovered within either Sarcodon or Hydnellum. In our ITS-only analyses nine species formed a well-supported clade of their own, separated from Sarcodon sensu stricto and Hydnellum (Fig.
The failure to generate support for Sarcodon and Hydnellum in the ITS-only analyses reflects the large genetical distances present among the species within this marker. Our general experience with the ITS region for thelephoralean target genera is that species are extremely well separated and the internal variation surprisingly low, even when a large number of specimens from both Europe and America are considered. On the other hand, the genetical difference among species is moderate to high, making alignments difficult and prone to ambiguities. In our ITS analyses we chose to remove ambiguous regions, thus halving the number of nucleotide positions suggested by automatic alignment through MAFFT. This seems to have affected the ML analyses most. However, the ITS analyses only served to position neotropical Sarcodon species and the results clearly show that they belong to a separate lineage.
The present study will serve as the basis for further exploration of species limits within Hydnellum and Sarcodon. As has been demonstrated for the genera, many species interpretations are in need of revision. Over the years we have found numerous specimen misidentifications as well as specimens that could not be assigned to pre-existing names. A closer inspection of the ITS tree in Fig.
This study was supported by grants from ArtsDatabanken, Norway, to KH Larsson (ADB54-09), from Artdatabanken, Sweden, to E Larsson (2014-152 4.3), and from Estonian Research Council to U Kõljalg (IUT20-30). We also acknowledge support to S Svantesson from Kungliga Vetenskaps- och Vitterhetssamhället i Göteborg and from Kapten Carl Stenholms donatationsfond. We are grateful to many dedicated mycologists in Norway, Sweden and Finland for sending valuable collections. We are especially grateful to Johan Nitare for sharing with us his outstanding knowledge of stipitate hydnoid fungi and for duplicates from his herbarium. We also thank Martyn Ainsworth and Terry Henkel whose thorough reviews improved this paper considerably.