Fungalpedia – Note 52 Hydnum
Hydnum L.
Citation if using this entry: Bera et al. (2023) Basidiomycota. Mycosphere (in prep)
Index Fungorum, MycoBank, GenBank, Fig. 1
The genus Hydnum has been quite popular in ethnomycological uses for centuries and often commonly being called “hedgehogs,” “sweet tooth,” or “wood urchins” (Niskanen et al. 2018). In accordance with the Linnean concept, all the mushrooms with spinose hymenophore were once accommodated under Hydnum which subsequently reflects the more than 900 names attributed to the genus as per Index Fungorum (www.indexfungorum.org) (Swenie et al. 2018). However, Hibbet et al. (1997) through molecular phylogeny revealed that the character spinose hymenophore has independently evolved multiple times in the distantly related taxa, and thus most of the misidentified species were moved to other genera later on (Swenie et al. 2018). As per Donk (1956), Hydnum (typified by H. repandum L.:Fr.) is characterized by white to orange basidiomata, stichic basidia, and smooth hyaline basidiospores (Donk 1933, Geesteranus 1971, Restivo & Petersen 1976, Pine et al. 1999). Geesteranus (1959) also described Hydnum as terrestrial mushroom with tomentum surfaced pileus and glabrescent to tomentose stipe, white to concolorous spined hymenium, homogenous context, and subglobose to ovoid basidiospores. The diversity of the ectomycorrhizal Hydnum has primarily been reported mainly from the temperate forests of Asia, Australia, Europe, and North America and few from tropical and subtropical forests of southeast Asia (Lee et al. 2002, Feng et al. 2016) and the neotropics (Garibay-Orijel et al. 2006, Sarmiento & Fontecha 2013, Feng et al. 2016, Niskanen et al. 2018, Swenie et al. 2018). The members of this genus have been found to be associated with a wide variety of plant species belonging to the family Pinaceae (Agerer et. al 1996), Myrtaceae (McNabb 1971), Fagales (McNabb 1971, Feng et al. 2016, Niskanen et al. 2018), Salicaceae (Niskanen et al. 2018), Malvaceae (Niskanen et al. 2018), and Dipterocarpaceae (Lee et al. 2002). Previously Feng et al. (2016) estimated only 12 species of Hydnum were commonly accepted worldwide. In recent times, the global revisionary study of the genus along with phylogenetic analysis has raised the species number up to 50 suggesting its unveiled diversity (Buyck et al. 2017, Niskanen et al. 2018, Swenie et al. 2018, Sugawara et al. 2022, Justo et al. 2023).
Type species: Hydnum repandum L.:Fr. 
Fig 1. Hydnum alboluteum (TUMH 6404, holotype). a. Basidiomata. b. Basidiospores. c. Basidia. d. Pileipellis. Scale bars: b-d = 10 μm. Drawn from Sugawara et al. 2022.
References
Agerer R, Kraigher H, Javornik B 1996 – Identification of ectomycorrhizae of Hydnum rufescens on Norway spruce and the variability if the ITS region of H. rufescens and H. repandum (Basidiomycetes). Nova Hedwigia, 63(1–2), 183–194. https://dialnet.unirioja.es/servlet/articulo?codigo=416517
Buyck B, Duhem B, Das K, Jayawardena RS, Niveiro N, Pereira OL, … & Hofstetter V 2017 – Fungal biodiversity profiles 21–30. Cryptogamie, Mycologie, 38(1), 101–146. https://core.ac.uk/reader/333623070
Donk MA 1933 – Revision der Niederlandischen Homobasidiomycetae-Aphyllophoraceae II. Mededelingen van de de Nederlandse Mycologische Vereeniging, 22, 1–278. https://repository.naturalis.nl/pub/534993
Donk MA 1956 – The Generic Names Proposed for Hymenomycetes V “Hydnaceae” (continuation). Taxon, 5(4), 69–80. https://onlinelibrary.wiley.com/doi/abs/10.2307/1217317
Feng B, Wang X-H, Ratkowsky D, Gates G, Lee SS, Grebenc T, Yang ZL 2016 – Multilocus phylogenetic analyses reveal unexpected abundant diversity and significant disjunct distribution pattern of the Hedgehog Mushrooms (Hydnum L.). Scientific Reports, 6(4), 1, 11. https://www.nature.com/articles/srep25586
Garibay-Orijel R, Cifuentes J, Estrada-Torres A, Caballero J 2006 – People using macro-fungal diversity in Oaxaca, Mexico. Fungal Diversity, 21, 41–67. https://www.fungaldiversity.org/fdp/sfdp/21-4.pdf
Geesteranus RA 1959 – The stipitate Hydnums of the Netherlands—IV. Auriscalpium SF Gray, Hericium Pers. ex SF Gray, Hydnum L. ex Fr., and Sistotrema Fr. em. Donk. Persoonia-Molecular Phylogeny and Evolution of Fungi, 1(1), 115–147. https://repository.naturalis.nl/pub/531660
Geesteranus RA 1971 – Hydnaceous fungi of the eastern old world. Verhandelingen Der Koninklijke Nederlandse Akademie Van Wetenschappen, 1–75. https://cir.nii.ac.jp/crid/1571135650785433984
Hibbett DS, Pine EM, Langer E, Langer G, Donoghue MJ 1997 – Evolution of gilled mushrooms and puffballs inferred from ribosomal DNA sequences. Proceedings of the National Academy of Sciences, 94(22), 12002–12006. https://www.pnas.org/doi/full/10.1073/pnas.94.22.12002
Justo A, Hood AW, Swenie RA, Matheny PB 2023 – Hydnum atlanticum, a new species from Eastern North America. Fungal Systematics and Evolution, 11, 63–70. https://www.ingentaconnect.com/content/wfbi/fuse/pre-prints/content-f5_fuse_vol11_art5
Lee SS, Watling R, Noraini-Sikin Y 2002 – Ectomycorrhizal basidiomata fruiting in lowland forests of Peninsular Malaysia. Bois et Forêts des Tropiques, 274, 33–43. https://pascal-francis.inist.fr/vibad/index.php?action=getRecordDetail&idt=13968883
McNabb RFR 1971 – Some new and revised taxa of New Zealand Basidiomycetes (Fungi). New Zealand Journal of Botany, 9(2), 355–370. https://www.tandfonline.com/doi/abs/10.1080/0028825X.1971.10429148
Niskanen T, Liimatainen K, Nuytinck J, Kirk P, Ibarguren IO, Garibay-Orijel R, … & 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. https://www.tandfonline.com/doi/abs/10.1080/00275514.2018.1477004?journalCode=umyc20
Pine EM, Hibbett DS, Donoghue MJ 1999 – Phylogenetic relationships of cantharelloid and clavaroid Homobasidiomycetes based on mitochondrial and nuclear rDNA sequences. Mycologia, 91, 944–963. https://www.tandfonline.com/doi/abs/10.1080/00275514.1999.12061105
Restivo JH, Petersen RH 1976 – Studies on Nuclear Division and Behavior within Basidia in Hydnum umbilicatum. Mycologia, 68(3), 666–672. https://www.tandfonline.com/doi/abs/10.1080/00275514.1976.12019951
Sarmiento E, Fontecha G 2013 – Conocimiento tradicional de los hongos en el occidente de Honduras. Revista Ciencia Y Tecnología, 13, 19–29. https://www.camjol.info/index.php/RCT/article/view/1710
Sugawara R, Maekawa N, Sotome K, Nakagiri A, Endo N 2022 – Systematic revision of Hydnum species in Japan. Mycologia, 114(2), 413–452. https://www.tandfonline.com/doi/abs/10.1080/0028825X.1971.10429148
Swenie RA, Baroni TJ, Matheny PB 2018 – Six new species and reports of Hydnum (Cantharellales) from eastern North America. MycoKeys, 42, 35–72. https://mycokeys.pensoft.net/article/27369/
Entry by
Ishika Bera, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand
(Edited by Kevin D Hyde)