Hydnum repandum: Difference between revisions

'''''Hydnum repandum''''', commonly known as the '''sweet tooth''', '''pig's trotter''',<ref>{{cite book |last1=Arora |first1=David |title=Mushrooms demystified: a comprehensive guide to the fleshy fungi |date=1986 |publisher=Ten Speed Press |location=Berkeley |isbn=978-0-89815-169-5 |edition=Second}}</ref> '''wood hedgehog''' or '''hedgehog mushroom''', is a [[basidiomycete]] fungus of the family [[Hydnaceae]]. First [[species description|described]] by [[Carl Linnaeus]] in 1753, it is the [[type species]] of the genus ''[[Hydnum]]''. The fungus produces [[fruit bodies]] (mushrooms) that are characterized by their [[Basidiospore|spore]]-bearing structures—in the form of spines rather than [[lamella (mycology)|gills]]—which hang down from the underside of the [[pileus (mycology)|cap]]. The cap is dry, colored yellow to light orange to brown, and often develops an irregular shape, especially when it has grown closely crowded with adjacent fruit bodies. The [[mushroom tissue]] is white with a pleasant odor and a spicy or bitter taste. All parts of the mushroom stain orange with age or when bruised.

A [[mycorrhiza]]l fungus, ''Hydnum repandum'' is broadly distributed in Europe <ref name="Swenie Baroni Matheny pp. 35–72">{{cite journal | last1=Swenie | first1=Rachel A. | last2=Baroni | first2=Timothy J. | last3=Matheny | first3=P. Brandon | title=Six new species and reports of Hydnum (Cantharellales) from eastern North America | journal=MycoKeys | publisher=Pensoft Publishers | volume=42 | date=2018-11-30 | issue=42 | issn=1314-4049 | doi=10.3897/mycokeys.42.27369 | pages=35–72| pmid=30564052 | pmc=6286385 | doi-access=free }}</ref> where it fruits singly or in close groups in [[coniferous]] or [[deciduous]] woodland.<ref name="Nature">{{cite journal | title=Multilocus phylogenetic analyses reveal unexpected abundant diversity and significant disjunct distribution pattern of the Hedgehog Mushrooms ( Hydnum L.) - Scientific Reports | journal=Scientific Reports | date=6 May 2016 | volume=6 | issue=1 | page=25586 | doi=10.1038/srep25586 | last1=Feng | first1=Bang | last2=Wang | first2=Xiang-Hua | last3=Ratkowsky | first3=David | last4=Gates | first4=Genevieve | last5=Lee | first5=Su See | last6=Grebenc | first6=Tine | last7=Yang | first7=Zhu L. | pmid=27151256 | pmc=4858670 | bibcode=2016NatSR...625586F }}</ref><ref name="Wildflowers, wild orchids, fungi, wildlife; nature books, reserves">{{cite web | title=Hydnum repandum, Wood Hedgehog mushroom | website=Wildflowers, wild orchids, fungi, wildlife; nature books, reserves | url=https://www.first-nature.com/fungi/hydnum-repandum.php | access-date=2019-11-18}}</ref> This is a choice [[edible mushroom|edible]] species, although mature specimens can develop a bitter taste. It has no poisonous lookalikes. Mushrooms are collected and sold in local markets of Europe and Canada.<ref name="Meronwood">{{cite web | title=Hedgehogs (Hydnum repandum) | website=Meronwood | url=http://meronwood.com/hedgehog-mushrooms-hydnum-repandum/ | access-date=2019-11-18}}</ref>

[[Molecular phylogenetics|Molecular]] studies have shown that the current [[species concept]] for ''H.&nbsp;repandum'' needed revision as there was a poor overlap between [[morphology (biology)|morphological]] and molecular species concepts. A 2009 [[Phylogeneticphylogenetic]] analysis of European specimens, based on [[internal transcribed spacer]] and 5.8S DNA sequences, indicated that ''H.&nbsp;repandum'' specimens form two distinct [[clade]]s, whose only consistent morphological distinction is cap size. These genetic differences foreshadowed the presence of undescribed [[cryptic species]], and that the taxon may currently be undergoing intensive [[speciation]].<ref name="Grebenc 2009"/> A comprehensive genetic study published in 2016 of members of the genus worldwide found that there are at least four species in the broad concept of ''H.&nbsp;repandum'': two species from southern China, one from Europe and eastern North America, and ''H.&nbsp;repandum'' itself from Europe, western North America, and northern (and alpine southwestern) China and Japan. Although it is missing from Central America, genetic material has been recovered from Venezuela from the tree ''[[Pakaraimaea|Pakaraimaea dipterocarpacea]]'', suggesting it somehow migrated there and had changed hosts.<ref name=feng16/>

The orange-, yellow- or tan-colored [[Pileus (mycology)|pileus]] (cap) is up to {{convert|17|cm|in|frac=2|abbr=on}} wide, although specimens measuring {{convert|25|cm|in|abbr=on|sigfig=1}} have been documented. It is generally somewhat irregular in shape (itpossibly may bebeing convex or concave at maturity), with a wavy margin that is rolled inward when young.<ref name="Arora 1986"/> Caps grow in a distorted shape when [[fruit bodies]] are closely clustered.<ref name="Laessoe 2002"/> The cap surface is generally dry and smooth, although mature specimens may show cracking.<ref name="Arora 1986"/> Viewed from above, the caps of mature specimens resemble somewhat those of chanterelles.<ref name="urlHydnum repandum (MushroomExpert.Com)"/> The [[trama (mycology)|flesh]] is thick, white, firm, brittle, and bruises yellow to orange-brown. The underside is densely covered with small, slender whitish spines measuring {{convert|2|–|7|mm|in|frac=3216|abbr=on}} long.<ref name="Arora 1986"/> These spines sometimes run down at least one side of the [[stipe (mycology)|stipe]].<ref name="Pegler 1997"/> The stipe, typically {{convert|3|–|10|cm|in|frac=2|abbr=on}} long and {{convert|1|–|3|cm|in|frac=4|abbr=on}} thick, is either white or the same color as the cap, and is sometimes off-center.<ref name="Arora 1986"/> It is easy to overlook the mushrooms when they are situated amongst [[agaric|gilled mushrooms]] and [[bolete]]s, because the cap and stipe are fairly nondescript and the mushrooms must be turned over to reveal their spines.<ref name="Abel 1993"/> The pure white variety of this species, ''H.&nbsp;repandum'' var. ''album'', is smaller than the main variety, with a cap measuring {{convert|2|–|7|cm|in|frac=2|abbr=on}} wide and a stipe that is {{convert|1|–|3|cm|in|frac=4|abbr=on}} long.<ref name="Roody 2003"/>

The [[spore print]] is pale [[cream (colour)|cream]]. [[Basidiospore]]s are smooth, thin-walled and [[hyaline]] (translucent), roughly spherical to broadly egg-shaped, and measure 5.5–7.5 by 4.5–5.5&nbsp;[[micrometre|µmμm]]. They usually contain a single, large [[refraction|refractive]] oil droplet. The [[basidia]] (spore-bearing cells) are club-shaped, four-spored, and measure 30–45 by 6–10&nbsp;µmμm. The [[cap cuticle]] is a trichodermium (where the outermost [[hypha]]e emerge roughly parallel, like hairs, perpendicular to the cap surface) of narrow, club-shaped cells that are 2.5–4&nbsp;µmμm wide. Underneath this tissue is the subhymenial layer of interwoven hyphae measuring 10–20&nbsp;µmμm in diameter. The spine tissue is made of narrow (2–5&nbsp;µmμm diameter), thin-walled hyphae with [[clamp connection]]s.<ref name="Pegler 1997"/>

North American lookalikes include the white hedgehog (''[[Hydnum albidum]]'') and the giant hedgehog (''[[Hydnum albomagnum|H.&nbsp;albomagnum]]''). ''H.&nbsp;albidum'' has a white to pale yellowish grey fruit body that bruises yellow to orange. ''H.&nbsp;albomagnum'' is large and paler than ''H.&nbsp;repandum''.<ref name="Roberts 2011" /> ''[[Hydnum umbilicatum]]'' is smaller, with caps measuring {{convert|3|–|5|cm|in|frac=2|abbr=on}} in diameter, and thinner stipes that are {{convert|0.5|–|1|cm|in|frac=4|abbr=on}} wide.<ref name="Davis 2012" /> Its caps are umbilicate (with a navel-like cavity), sometimes with a hole in the center of the cap,<ref name="Laessoe 2002" /> unlike the flattened or slightly depressed caps of ''H.&nbsp;repandum''.<ref name="Roody 2003" /> Microscopically, ''H.&nbsp;umbilicatum'' has spores that are larger and more elliptical than those of ''H.&nbsp;repandum'', measuring 7.5–9 by 6–7.5&nbsp;µmμm.<ref name="urlHydnum" repandum (MushroomExpert.Com)"/> A European lookalike, ''[[Hydnum rufescens|H.&nbsp;rufescens]]'', is also smaller than ''H.&nbsp;repandum'', and has a deeper [[apricot (color)|apricot]] to orange color.<ref name="Sterry 2009" /> ''[[Hydnum ellipsosporum]]'', described as a new species from Germany in 2004, differs from ''H.&nbsp;repandum'' by the shape and length of its spores, which are [[ellipsoid]] and measure 9–11 by 6–7.5&nbsp;µmμm. Compared to ''H.&nbsp;repandum'', it has smaller fruit bodies, with cap diameters ranging from {{convert|3|to|5|cm|in|frac=2|abbr=on}} wide.<ref name="Ostrow 2004" />

== Ecology, habitatHabitat and distribution ==

''H. repandum'' is a [[mycorrhiza]]l fungus.<ref name="Laessoe 2002"/> The fruit bodies grow singly, scattered, or in groups on the ground or in [[leaf litter]] in both [[coniferous forest|coniferous]] and [[deciduous forest]]s.<ref name="Arora 1986"/><ref name="Sterry 2009"/> They can also grow in [[fairy ring]]s.<ref name="Dickinson 1982"/> Fruiting occurs from summer to autumn.<ref name="Phillips 2005"/> The species is widely distributed in Europe, <ref name="Swenie Baroni Matheny pp. 35–72">{{cite journal | last1=Swenie | first1=Rachel A. | last2=Baroni | first2=Timothy J. | last3=Matheny | first3=P. Brandon | title=Six new species and reports of Hydnum (Cantharellales) from eastern North America | journal=MycoKeys | publisher=Pensoft Publishers | volume=42 | date=2018-11-30 | issue=42 | issn=1314-4049 | doi=10.3897/mycokeys.42.27369 | pages=35–72| pmid=30564052 | pmc=6286385 | doi-access=free }}</ref> and is one of the most common of the tooth fungi.<ref name="Arora 1986"/> In Europe, it has been listed as a [[vulnerable species]] in the [[Red Data List]]s of the [[Netherlands]], [[Belgium]], and [[Germany]]; [[Sweden]] lists it as being of [[Least Concern]].<ref name="Arnolds 2010"/> ''H. repandum'' alsodoes growsnot occur in OntarioCanada, but two related species do: ''[[Hydnum washingtonianum|H. washingtonianum]]'' and ''[[Hydnum subolympicum|H. subolympicum]]''.<ref name="Niskanen Liimatainen Nuytinck Kirk 2018 pp. 890–918">{{Citecite webjournal |title last1=ANiskanen Field| Guidefirst1=Tuula To| Mushroomslast2=Liimatainen In| Ontariofirst2=Kare ·| iNaturalistlast3=Nuytinck Canada| first3=Jorinde |url last4=https://inaturalist.ca/guides/12943Kirk |access first4=Paul | last5=Ibarguren | first5=Ibai Olariaga | last6=Garibay-Orijel | first6=Roberto | last7=Norvell | first7=Lorelei | last8=Huhtinen | first8=Seppo | last9=Kytövuori | first9=Ilkka | last10=Ruotsalainen | first10=Juhani | last11=Niemelä | first11=Tuomo | last12=Ammirati | first12=Joseph F. | last13=Tedersoo | first13=Leho | title=Identifying and naming the currently known diversity of the genus ''Hydnum'', with an emphasis on European and North American taxa | journal=Mycologia | publisher=Informa UK Limited | volume=110 | issue=5 | date=20222018-09-2103 |website issn=iNaturalist0027-5514 Canada| doi=10.1080/00275514.2018.1477004 |language pages=en890–918}}</ref>

==Nutrition Uses ==

East [[Black Sea region]] in Turkey. Source: {{cite journal |vauthors=Ayaz FA, Torun H, Özel A, Col M, Duran C, Sesli E, Colak A |year=2011 |title=Nutritional value of edible wild mushrooms collected from Black Sea region (Turkey) |journal=Turkish Journal of Biochemistry |volume=36 |issue=3 |pages=213–21 |url=http://www.turkjbiochem.com/2011/213-221.pdf |access-date=2013-09-09 |archive-date=2017-08-11 |archive-url=https://web.archive.org/web/20170811022211/http://turkjbiochem.com/2011/213-221.pdf |url-status=dead }}</ref>

| carbohydratecarbs=56.1 g

== Constituents =Culinary===

<ref name="Arnolds 2010">{{cite journal |author=Arnolds E. |title=The fate of hydnoid fungi in The Netherlands and Northwestern Europe |journal=Fungal Ecology |year=2010 |volume=3 |issue=2 |pages=81–88 |doi=10.1016/j.funeco.2009.05.005|bibcode=2010FunE....3...81A }}</ref>

<ref name="urlHydnum repandum (MushroomExpert.Com)">{{cite web |author=Kuo M. |url=http://www.mushroomexpert.com/hydnum_repandum.html |title=''Hydnum repandum'' |publisher=MushroomExpert.Com |date=August 2003 |access-date=8 September 2013}}</ref>