View source for Boletus edulis

{{Short description|Species of mushroom, widely distributed in the Northern Hemisphere}}
{{Redirect|Cep}}
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{{Featured article}}
{{Use British English|date=October 2015}}
{{Speciesbox
 | image = Boletus edulis IT.jpg
 | image_caption = In the northern [[Apennine Mountains]], Abetina Reale forest, Italy
 | image_alt = Two mushrooms with brown caps and light brown stems growing on the ground, surrounded by fallen leaves and other forest debris. One mushroom has been plucked and lies beside the other; its under-surface is visible, and is a light yellow colour.
 |status = LC
 |status_system = IUCN3.1
 |status_ref = <ref name=iucn>{{cite iucn |author=Dahlberg, A. |year=2019 |errata=2022 |title=''Boletus edulis'' |volume=2019 |page=e.T122090234A222968388 |doi=10.2305/IUCN.UK.2019-3.RLTS.T122090234A222968388.en |access-date=2 July 2024}}</ref>
 | genus = Boletus
 | species = edulis
 | authority = [[Jean Baptiste François Pierre Bulliard|Bull.]] (1782)
 | synonyms_ref= <ref name="urlMycoBank: Boletus edulis">{{cite web |url=http://www.mycobank.org/MycoTaxo.aspx?Link=T&Rec=356530 |title=''Boletus edulis'' Bull. 1782 |publisher=International Mycological Association |work=MycoBank |access-date=2010-10-21}}</ref>
 | synonyms = 
*''Ceriomyces crassus'' <small>[[Giovanni Antonio Battarra|Battarra]] (1775)</small>
*''Boletus solidus'' <small>[[James Sowerby|Sowerby]] (1809)</small>
*''Leccinum edule'' <small>(Bull.) [[Samuel Frederick Gray|Gray]] (1821)</small>
*''Dictyopus edulis'' <small>(Bull.) Forq. (1890)</small>
}}
{{Mycomorphbox
| name = ''Boletus edulis''
| whichGills = adnate
| capShape = convex
| hymeniumType = pores
| stipeCharacter = bare
| ecologicalType = mycorrhizal
| sporePrintColor = brown
| howEdible = choice
}}
'''''Boletus edulis''''' (English: '''cep''', '''penny bun''', '''porcino''') is a [[basidiomycete]] fungus, and the [[type species]] of the genus ''[[Boletus]]''. It is prized as an [[edible mushroom]]. 

The fungus produces [[Basidiospore|spore]]-bearing [[basidiocarp|fruit bodies]] above ground in summer and autumn. The fruit body has a large brown [[pileus (mycology)|cap]] which on occasion can reach {{convert|30|cm|0|abbr=on}}, rarely {{convert|40|cm|0|abbr=on}} in diameter and {{convert|3|kg|lboz|abbr=on}} in weight. Like other [[bolete]]s, it has tubes extending downward from the underside of the cap, rather than gills; spores escape at maturity through the tube openings, or pores. The pore surface of the ''B.&nbsp;edulis'' fruit body is whitish when young, but ages to a greenish-yellow. The stout [[Stipe (mycology)|stipe]], or stem, is white or yellowish in colour, up to {{convert|20|cm|0|abbr=on}}, rarely {{convert|30|cm|0|abbr=on}} tall and {{convert|10|cm|0|abbr=on}} thick, and partially covered with a raised network pattern, or [[wikt:reticulate|reticulations]].

The fungus grows in [[deciduous forest|deciduous]] and [[conifer]]ous forests and tree [[plantation]]s, forming [[symbiotic]] [[ectomycorrhiza]]l associations with living trees by enveloping the tree's underground roots with sheaths of fungal tissue. Widely distributed in the [[Northern Hemisphere]] across Eurasia and North America, it does not occur naturally in the Southern Hemisphere, although it has been [[introduced species|introduced]] to southern Africa, Australia, New Zealand, and Brazil. Several closely related European mushrooms formerly thought to be [[variety (botany)|varieties]] or [[form (botany)|forms]] of ''B.&nbsp;edulis'' have been shown using [[molecular phylogenetic]] analysis to be distinct species, and others previously classed as separate species are [[wikt:conspecific|conspecific]] with this species. The western North American species commonly known as the California king bolete (''Boletus edulis'' var. ''grandedulis'') is a large, darker-coloured variant first formally identified in 2007.

''B.&nbsp;edulis'' is held in high regard in many cuisines, and is commonly prepared and eaten in [[soups]], pasta, or [[risotto]]. The mushroom is low in fat and digestible [[carbohydrate]]s, and high in [[protein (nutrient)|protein]], [[vitamin]]s, [[dietary mineral|mineral]]s and [[dietary fibre]]. Although it is sold commercially, it is very difficult to [[fungiculture|cultivate]]. Available fresh in autumn throughout Europe and Russia, it is most often dried, packaged, and distributed worldwide. It keeps its flavour after drying, and it is then reconstituted and used in cooking. ''B.&nbsp;edulis'' is also one of the few fungi sold [[pickled]].

==Taxonomy==
[[File:Bulliard00.jpg|thumb|Pierre Bulliard first described ''B.&nbsp;edulis'' in 1782.|alt=Side view of the head and upper body of a man wearing a dark jacket and white ruffled collar.]]

''Boletus edulis'' was first [[species description|described]] in 1782 by the French botanist [[Jean Baptiste François Pierre Bulliard|Pierre Bulliard]] and still bears its original name.<ref>{{cite book |title=Herbier de la France. Vol 2|author=Bulliard JBF.|year=1782|publisher=P.F. Didot|location=Paris, France|pages=49–96, plate 60|url=https://archive.org/stream/herbierdelafranc4996bull#page/22/mode/2up|access-date=2009-11-24|language=fr}}</ref> The starting date of fungal [[Taxonomy (biology)|taxonomy]] had been set as January&nbsp;1, 1821, to coincide with the date of the works of the 'father of mycology', Swedish naturalist [[Elias Magnus Fries]], which meant the name required sanction by Fries (indicated in the name by a colon) to be considered valid, as Bulliard's work preceded this date. It was thus written ''Boletus edulis'' Bull.:Fr. A 1987 revision of the [[International Code of Botanical Nomenclature]] set the starting date at May&nbsp;1, 1753, the date of publication of [[Carl Linnaeus|Linnaeus]]' work, the ''[[Species Plantarum]]''.<ref>{{cite book |vauthors=Esser K, Lemke PA |title= The Mycota: A Comprehensive Treatise on Fungi as Experimental Systems for Basic and Applied Research |url=https://archive.org/details/mossflorabritain00libg |url-access=limited |publisher = Springer|location=Heidelberg, Germany |year=1994|page=[https://archive.org/details/mossflorabritain00libg/page/n93 81]|isbn = 3-540-66493-9}}</ref> Hence, the name no longer requires the ratification of Fries' authority. Early [[synonym (taxonomy)|alternate names]] include ''Boletus solidus'' by English naturalist [[James Sowerby]] in 1809,<ref>{{cite book |title=Coloured Figures of English Fungi |volume=4 |author=Sowerby J.|year=1809|publisher=J. Davis |location=London |page=199}} This entire work is [[commons:Coloured Figures of English Fungi or Mushrooms|available in Commons here]], but the reference is to plate 419 with textual description on page 697. Sowerby described the same modern species as ''B. edulis'' on plate 111 (description on page 57).</ref> and [[Samuel Frederick Gray|Gray's]] ''Leccinum edule''.<ref>{{cite book |title=A Natural Arrangement of British Plants |author=Gray SF. |year=1821 |publisher=Baldwin, Cradock, and Joy, Paternoster-Row |location=London |page=647 |url=https://books.google.com/books?id=g-EYAAAAYAAJ&q=A%20natural%20arrangement%20of%20British%20plants%20Gray%201821&pg=PA647|access-date=2009-11-24}}</ref> Gray's transfer of the species to ''Leccinum'' was later determined to be inconsistent with the rules of botanical [[biological classification|nomenclature]], and he apparently was unfamiliar with the earlier works of Fries when he published his arrangement of bolete species.<ref>{{cite journal|author= Šutara J. |year=1985 |title=''Leccinum'' and the question of superfluous names (Fungi: Boletaceae) |journal=Taxon |volume=34 |issue=4 |pages=678–86|doi= 10.2307/1222214|jstor= 1222214}}</ref>

''Boletus edulis'' is the [[type species]] of the genus ''[[Boletus]]''. In [[Rolf Singer]]'s [[biological classification|classification]] of the [[Agaricales]] mushrooms, it is also the type species of [[Section (botany)#Ranks in botany|section]] ''Boletus'', a grouping of about 30 related boletes united by several characteristics: a mild-tasting, white [[trama (mycology)|flesh]] that does not change colour when exposed to air; a smooth to distinctly raised, netted pattern over at least the uppermost portion of the stem; a yellow-brown or olive-brown [[spore print]]; white tubes that later become yellowish then greenish, which initially appear to be stuffed with cotton; and [[cystidia]] that are not strongly coloured.<ref name=Singer1986>{{cite book |author=Singer R. |title=The Agaricales in Modern Taxonomy |edition= 4th rev.|publisher=Koeltz Scientific Books|location=Koenigstein, Germany |year=1986|page=779|isbn=3-87429-254-1}}</ref><ref>{{cite book |vauthors=Smith AH, Thiers HD |year=1971 |title=The Boletes of Michigan |location=Ann Arbor, Michigan|publisher=University of Michigan Press|page=221|url=http://quod.lib.umich.edu/cgi/t/text/pageviewer-idx?c=fung1tc;cc=fung1tc;idno=agk0838.0001.001;frm=frameset;view=image;seq=229;page=root;size=s|access-date=2010-12-02}}</ref> [[Molecular phylogenetics|Molecular]] analysis published in 1997 established that the bolete mushrooms are all [[monophyly|derived from a common ancestor]], and established the [[Boletales]] as an [[order (biology)|order]] separate from the Agaricales.<ref>{{cite journal |vauthors=Binder M, Besl H, Bresinsky A |year=1997 |title=Agaricales oder Boletales? Molekularbiologische Befunde zur Zuordnung einiger umstrittener Taxa |journal=Zeitschrift für Mykologie |volume=63 |pages=189–196 }}</ref>

The [[genus|generic]] name is derived from the [[Latin]] term ''bōlētus'' "mushroom", which was borrowed in turn from the [[Ancient Greek]] βωλίτης, "terrestrial fungus".<ref>{{cite book |author= Simpson DP. |title=Cassell's Latin Dictionary |publisher = Cassell Ltd |year = 1979 |orig-date=1854 |edition = 5 |location = London |page=78 |isbn = 0-304-52257-0}}</ref> Ultimately, this last word derives from ''bōlos''/βῶλος "lump", "clod", and, metaphorically, "mushroom".<ref name="Liddell 1980">{{cite book |author = [[Henry Liddell|Liddell HG]], [[Robert Scott (philologist)|Scott R.]] |year= 1980 |title = A Greek–English Lexicon|edition= Abridged |publisher = [[Oxford University Press]] | location= United Kingdom |isbn = 0-19-910207-4|title-link= A Greek–English Lexicon }}</ref> The βωλίτης of [[Galen]], like the ''boletus'' of Latin writers like [[Martial]], [[Seneca the Younger|Seneca]] and [[Petronius]],<ref>Peter Howell, ''A Commentary on Book One of the Epigrams of Martial,'' The Athlone Press, 1980 p.152-3. Howell doubts the identification, and mentions the view advanced by Augusta A. Imholtz Jr., 'Fungi and piace- names, thè origin of boletus,' in [[American Journal of Philology|AJP]] Vol.98, 1977 pp.71f., that the Latin word may derive from the Spanish town Boletum, modern-day [[Boltaña]], south of the [[Pyrenees]], which is still famous for its mushrooms.</ref> is often identified as the much prized ''[[Amanita caesarea]]''.<ref name = "Ramsbottom53">{{cite book |author=Ramsbottom J. |orig-year=1953 |year=1989|title=Mushrooms & Toadstools |page=6 |publisher=Collins |location=London, England|isbn= 1-870630-09-2}}</ref> The [[specific name (botany)|specific epithet]] ''edulis'' in Latin means "eatable" or "edible".<ref>{{cite book|vauthors=Jamieson A, Ainsworth R, Morell T | title = Latin Dictionary: Morell's Abridgment | publisher = Moon, Boys & Graves| year = 1828|location = London|pages = [https://archive.org/details/bub_gb_U3oTAAAAYAAJ/page/n550 121], 596| url=https://archive.org/details/bub_gb_U3oTAAAAYAAJ|access-date=2009-11-02}}</ref>

===Common names===
[[Common name]]s for ''B. edulis'' vary by region. The standard Italian name, ''porcino'' (pl. ''porcini''), means ''[[wikt:porcine|porcine]];''<ref>{{Cite web|url=https://www.treccani.it/vocabolario/porcino|title=porcino in Vocabolario – Treccani|website=www.treccani.it}}</ref> ''fungo porcino'', in Italian, echoes the term ''suilli'', literally "hog mushrooms", a term used by the Ancient Romans<ref>[[Pliny the Elder|Pliny]], ''Natural History'', Bk. 16, 11, 31: "Such is the multiplicity of products in addition to the acorn that are borne by hard-oaks; but they also produce edible fungi (''boletos'') and hog mushrooms (''suillos'')." Pliny, ''Natural History'', 10 vols., tr. H. Rackham, Harvard University Press/Heinemann, (1945) 1968, vol. 4, pp. 408–409.</ref> and still in use in southern Italian terms for this species.<ref>[[Neapolitan language|Neapolitan]] ''sillo'', and [[Calabrian dialects|Calabrian]] ''sillu''/''siddu''. See Glauco Sanga, Gherardo Ortalli, ''Nature knowledge: ethnoscience, cognition, and utility'', Berghahn Books, 2003 p. 78.</ref> The derivation has been ascribed to the resemblance of young fruit bodies to piglets, or to the fondness pigs have for eating them.<ref name="Carluccio03">Carluccio, pp. 36–38.</ref> It is also known as "king bolete".<ref name=Zeitl76>{{cite book|author=Zeitlmayr L.|year=1976|title=Wild Mushrooms: An Illustrated Handbook|publisher=Garden City Press|location= Hertfordshire, UK|isbn= 0-584-10324-7|page=96}}</ref> The English ''[[penny bun]]'' refers to its rounded brownish shape. The German name ''Steinpilz'' (stone mushroom) refers to the species' firm flesh.<ref>{{cite book|author=[[Jacob Grimm|Grimm J.]], [[Wilhelm Grimm|Grimm W.]]|title=Deutsches Wörterbuch|publisher=Hirzel|location=Leipzig|date=1838–1961|title-link=Deutsches Wörterbuch}} ([http://www.woerterbuchnetz.de/woerterbuecher/dwb/wbgui?lemid=GS42864 online] {{Webarchive|url=https://web.archive.org/web/20110719114321/http://www.woerterbuchnetz.de/woerterbuecher/dwb/wbgui?lemid=GS42864 |date=2011-07-19 }})</ref> In Austria, it is called ''Herrenpilz'', the "noble mushroom",<ref name = "Carluccio03"/> while in Mexico, the Spanish name is ''panza'', meaning "belly".<ref>{{cite journal |vauthors=Jarvis MC, Miller AM, Sheahan J, Ploetz K, Ploetz J, Watson RR, Ruiz MP, Villapan CA, Alvarado JG, Ramirez AL, Orr B |year=2004 |title=Edible wild mushrooms of the Cofre de Perote region, Veracruz, Mexico: An ethnomycological study of common names and uses |journal=Economic Botany |volume=58 |issue=Suppl. S |pages=S111–S115|doi=10.1663/0013-0001(2004)58[S111:EWMOTC]2.0.CO;2|s2cid=27729532 }}</ref> Another Spanish name, ''rodellon'', means "small round boulder", while the [[Dutch language|Dutch]] name ''eekhoorntjesbrood'' means "squirrel's bread".<ref name=Schalkwijk-Barendsen1991>{{cite book |author=Schalkwijk-Barendsen H. M. E. |title=Mushrooms of Western Canada |publisher=Lone Pine Publishing |location=Edmonton |year=1991 |page=[https://archive.org/details/mushroomsofweste0000scha/page/195 195] |isbn=0-919433-47-2 |url=https://archive.org/details/mushroomsofweste0000scha/page/195 }}</ref> Russian names are ''belyy grib'' ([[:ru:белый гриб]]; "white mushroom" as opposed to less valuable "black mushrooms") and ''borovik'' ([[:ru:боровик]]; from ''bor''—"pine forest").
The vernacular name ''cep'' is derived from the [[Catalan language|Catalan]] ''cep'' or its French name ''cèpe'', although the latter is a generic term applying to several related species. In France, it is more fully ''cèpe de Bordeaux'', derived from the [[Gascon language|Gascon]] ''cep'' "trunk" for its fat stalk,<ref>{{cite book |author=Grigson J. |title=The Mushroom Feast |page=[https://archive.org/details/mushroomfeast00grig/page/8 8] |year=1975 |publisher=Penguin |location=London |isbn=0-14-046273-2 |url=https://archive.org/details/mushroomfeast00grig/page/8 }}</ref> ultimately from the [[Latin]] ''cippus'' "stake".<ref>{{Cite encyclopedia| title=cepe|encyclopedia=Oxford English Dictionary|editor1=J. Simpson |editor2=E. Weiner | year=1989 |edition= 2nd| location=Oxford |publisher=Clarendon Press|isbn= 0-19-861186-2}}</ref> ''Ceppatello'', ''ceppatello buono'', ''ceppatello bianco'', ''giallo leonato'', ''ghezzo'', and ''moreccio'' are names from Italian dialects,<ref>{{cite book|author=Naccari N. L.|title=Flora veneta|publisher=L. Bonvecchiato|year=1827|volume=4–6|page=10}}</ref><ref>{{cite book|author=Zeitlmayr L.|title=I funghi|publisher=Edizioni Studio Tesi|year=1977|page=180}}</ref> and ''ciurenys'' or ''surenys'' is another term in Catalan.<ref>{{cite book|last=Andrews|first=Colman |title=Catalan cuisine: vivid flavors from Spain's Mediterranean coast|publisher=Harvard Common Press|location=Boston, MA|year=1999|orig-date=1988|edition=2nd|page=88|isbn=1-55832-329-5}}</ref> The French-born King [[Charles XIV John]] popularised ''B.&nbsp;edulis'' in Sweden after 1818,<ref>{{cite book|vauthors=Spoerke DG, Rumack BH |title=Handbook of Mushroom Poisoning: Diagnosis and Treatment|publisher=CRC Press|location=Boca Raton, Florida|year=1994|page=11|isbn=0-8493-0194-7}}</ref> and is honoured in the local vernacular name ''Karljohanssvamp'', as well as the Danish name ''Karl Johan svamp''. The monarch cultivated the fungus about his residence, [[Rosersberg Palace]].<ref>{{cite book|vauthors=Stensaas M, Sonstegard J |title=Canoe Country Flora: Plants and Trees of the North Woods and Boundary Waters |publisher=University of Minnesota Press|location=Minneapolis, Minnesota|year=2004|page=189|isbn=1-57025-121-5}}</ref> The Finnish name is ''herkkutatti'', from ''herkku'' 'delicacy', and ''tatti'', 'bolete'.{{Cn|date=December 2024}}

==Description==
[[File:Boletus edulis herkkutatti halki.jpg|thumb|alt=Both halves of a thick-stemmed bisected mushroom.|Cross-section showing white flesh, broad stem, and spore tubes on the cap's underside]]

The [[Pileus (mycology)|cap]] of this mushroom is {{convert|7–30|cm|frac=2|abbr=on}} broad at maturity. Slightly sticky to touch, it is convex in shape when young and flattens with age. The colour is generally reddish-brown fading to white in areas near the margin, and continues to darken as it matures. The [[Stipe (mycology)|stipe]], or stem, is {{convert|8–25|cm|frac=2|abbr=on}} in height, and up to {{convert|7|cm|frac=2|abbr=on}} thick—rather large in comparison to the cap;<ref name=Kozikowski1996/> it is club-shaped, or bulges out in the middle. It is finely [[wikt:reticulate|reticulate]] on the upper portion, but smooth or irregularly ridged on the lower part. The under surface of the cap is made of thin tubes, the site of [[Basidiospore|spore]] production; they are {{convert|1 to 2|cm|frac=4|abbr=on}} deep, and whitish in colour when young, but mature to a greenish-yellow.<ref name=Grund1976/> The angular pores, which do not stain when bruised, are small—roughly 2 to 3 pores per millimetre.<ref name=Tylutki1987II>{{cite book|title=Mushrooms of Idaho and the Pacific Northwest. Vol. 2. Non-gilled Hymenomycetes|author=Tylukti EE. |year=1987 |publisher=The [[University of Idaho Press]] |location=Moscow, Idaho|pages=9–10 |isbn= 0-89301-097-9}}</ref> In youth, the pores are white and appear as if stuffed with cotton (which are actually [[mycelia]]); as they age, they change colour to yellow and later to brown. The spore print is olive brown. The flesh of the fruit body is white, thick and firm when young, but becomes somewhat spongy with age. When bruised or cut, it either does not change colour, or turns a very light brown or light red.<ref name=Wang1995/> Fully mature specimens can weigh about {{convert|1|kg|lboz|abbr=on}}; a huge specimen collected on the [[Isle of Skye]], Scotland, in 1995 bore a cap of {{convert|42|cm|frac=2|abbr=on}}, with a stipe {{convert|18|cm|frac=2|abbr=on}} in height and {{convert|14|cm|frac=2|abbr=on}} wide, and weighed {{convert|3.2|kg|lboz|abbr=on}}.<ref name=Kozikowski1996>{{cite journal|author=Kozikowski GR.|year=1996 |title=Foray Report from Skye |journal=Mycologist |volume=10 |pages=183–84 |doi=10.1016/S0269-915X(96)80022-X |issue=4}}</ref> A similarly sized specimen found in Poland in 2013 made international news.<ref>{{Cite news | url=https://www.bbc.co.uk/news/world-europe-24292021 | title=Giant mushroom found in Poland| work=BBC News}}</ref>
{{multiple image
| align = left
| image1 = Boletus edulis (7).jpg
| width1 = 72
| alt1 = A brown-capped mushroom lying flat on the grass with a white or light-brown coloured stem that gradually gets thicker, so as to roughly resemble the shape of a club.
| caption1 = 
| image2 = Boletus edulis JPG9.jpg
| width2 = 128
| alt2 = A brown-capped mushroom with a short, stout stem that is thickest in the middle, and whose thickness approaches the width of the cap it supports.
| caption2 = 
| footer = Stem shape can range from club-shaped to centrally bulbous
}}
''Boletus edulis'' is considered one of the safest wild mushrooms to pick for the table, as few poisonous species closely resemble it, and those that do may be easily distinguished by careful examination.<ref name = "Carluccio03"/> The most similar poisonous mushroom may be the devil's bolete (''[[Rubroboletus satanas]]''), which has a similar shape, but has a red stem and stains blue on bruising.<ref name="Carluccio03" /> It is often confused with the very bitter and unpalatable ''[[Tylopilus felleus]]'', but can be distinguished by the reticulation on the stalk; in porcini, it is a whitish, net-like pattern on a brownish stalk, whereas it is a dark pattern on white in the latter. Porcini have whitish pores while the other has pink. If in doubt, tasting a tiny bit of flesh will yield a bitter taste.<ref name = "Carluccio03"/> It can also resemble the "bolete-like" ''[[Gyroporus castaneus]]'', which is generally smaller, and has a browner stem. ''[[Boletus huronensis]],'' an uncommon mushroom of northeastern North America, is another recognized look-alike known to cause severe [[gastrointestinal disorder]]s.<ref>{{cite web|url=https://namyco.org/boletus_huronensis.php|title=''Boletus huronensis'': Comments on its toxicity with diagnostic images of its field characteristics and staining reactions|author=Bill Bakaitis|publisher=North American Mycological Association|date=2019}}</ref>

The spores are elliptical to spindle-shaped, with dimensions of 12–17 by 5–7&nbsp;[[μm]]. The [[basidia]], the spore-bearing cells, are produced in a layer lining the tubes, and arrange themselves so their ends are facing the center of the tube; this layer of cells is known technically as a [[hymenium]]. The basidia are thin-walled, mostly attached to four spores, and measure 25–30 by 8–10&nbsp;μm. Another cell type present in the hymenium is the cystidia, larger sterile cells that protrude beyond the basidia into the [[lumen (anatomy)|lumen]] of the hymenium, and act as air traps, regulating humidity.<ref>{{cite book|vauthors=Alexopoulos CJ, Mims CW, Blackwell M | title=Introductory Mycology | year=1996 | publisher=John Wiley and Sons |location=New York|page=495 | isbn=0-471-52229-5}}</ref> ''B.&nbsp;edulis'' has pleurocystidia (cystidia located on the face of a pore) that are thin-walled, roughly spindle-shaped to [[ventricose]], and measure 30–45 by 7–10&nbsp;μm; the "stuffed" feature of the hymenium is caused by cheilocystidia—cells found on the edges of the pores.<ref name=Grund1976>{{cite book |title=Nova Scotian Boletes |vauthors=Grund DW, Harrison AK |year=1976 |publisher=J. Cramer |location=Lehre, Germany |isbn=3-7682-1062-6|pages=73–75}}</ref> The [[hypha]]e of ''B.&nbsp;edulis'' do not have [[clamp connection]]s.<ref name=Tylutki1987II/>

===Related species===
{{multiple image
| align = right
| image1 = Boletus edulis var. grandedulis 27911.jpg
| width1 = 100
| alt1 = A mushroom with an orange-brown cap and a yellowish underside that somewhat resembles a sponge. The light-yellow stem is about half the thickness of the caps diameter. This mushroom is growing on the ground, surrounded by twigs, leaves, log and other forest floor debris.
| caption1 = ''B. edulis'' var. ''grandedulis''
| image2 = Boletus regineus 28082.jpg
| width2 = 100
| alt2 = A mushroom with a reddish-brown cap that is curled upwards to reveal a cream-coloured porous underside that somewhat resembles a sponge. The thick stipe has a pinkish hue, and its thickness is a little less than half of the cap's diameter. The mushroom has been pulled from the ground and the end of its stipe is a whitish colour caused by hyphal tufts, and is embedded with dirt and other small twigs.
| caption2 = ''B. regineus''
| footer = 
}}
Several similar brownish-coloured species are sometimes considered subspecies or forms of this mushroom. In Europe, in addition to ''B.&nbsp;edulis'' (or ''cèpe de Bordeaux''), the most popular are:
*''Cèpe bronzé'' ("dark cep"; ''[[Boletus aereus]]''), much rarer than ''B.&nbsp;edulis'', is more highly regarded by gourmets, and consequently more expensive. Usually smaller than ''B.&nbsp;edulis'', it is also distinctively darker in colour.<ref name = "Carluccio03"/> It is especially suited to drying.<ref name=Zeitl76/>
*''Cèpe des pins'' ("pine tree cep"; ''[[Boletus pinophilus]]'' or ''Boletus pinicola'') grows among pine trees. Rarer than ''B.&nbsp;edulis'', it is less appreciated by gourmets than the two other kinds of porcini, but remains a mushroom rated above most others.<ref name=Zeitl76/>
*''Cèpe d'été'' ("summer cep"; ''[[Boletus reticulatus]]''), also less common and found earlier.<ref name = "Carluccio03"/>

[[Molecular phylogenetic]] analyses have proven these three are all distinctive and separate species;<ref>{{cite journal |vauthors=Vizzini A, Mello A, Ghignone S, Sechi C, Ruiu P, Bonfante P |year=2008 |title=''Boletus edulis'' complex: from phylogenetic relationships to specific primers |journal=Pagine di Micologia |issue=30 |pages=49–52 |issn=1122-8911}}</ref> other taxa formerly believed to be unique species or subspecies, such as ''B.&nbsp;betulicola'', ''B.&nbsp;chippewaensis'', ''B.&nbsp;persoonii'', ''B.&nbsp;quercicola'' and ''B.&nbsp;venturii'', are now known to be part of a ''B.&nbsp;edulis'' [[species complex]] with a wide [[morphology (biology)|morphological]], ecological and geographic range,<ref>{{cite journal |author1=Beugelsdijk DCM |author2=van der Linde S |author3=Zuccarello GC |author4=den Bakker |author5=Draisma SGA |author6=Noordeloos ME. |year=2008 |title= A phylogenetic study of ''Boletus'' section ''Boletus'' in Europe |journal=Persoonia |pmid= 20467482 |volume=20 |issue=1 |pmc= 2865352 |pages=1–7|doi=10.3767/003158508X283692 }}</ref><ref name=dent10>{{cite journal|vauthors=Dentinger BT, Ammirati JF, Both EE, Desjardin DE, Halling RE, Henkel TW, Moreau PA, Nagasawa E, Soytong K, Taylor AF, Watling R, Moncalvo JM, McLaughlin DJ |title=Molecular phylogenetics of porcini mushrooms (''Boletus'' section ''Boletus'') |journal=Molecular Phylogenetics and Evolution |volume=57 |year=2010 |pages=1276–1292 |url=http://static.msi.umn.edu/rreports/2010/211.pdf |doi=10.1016/j.ympev.2010.10.004 |issue=3 |pmid=20970511 |archive-url=https://web.archive.org/web/20130523094609/http://static.msi.umn.edu/rreports/2010/211.pdf |archive-date=2013-05-23 }}</ref> and that the genetic variability in this complex is low.<ref>{{cite journal|vauthors=Beugelsdijk DC, van der Linde S, Zuccarello GC, den Bakker HC, Draisma SG, Noordeloos ME |year=2008|title=A phylogenetic study of ''Boletus'' section ''Boletus'' in Europe|journal=Persoonia|volume=20|pages=1–7|pmid=20467482|doi=10.3767/003158508X283692|pmc=2865352}}</ref> Similar molecular technology has been developed to rapidly and accurately identify ''B.&nbsp;edulis'' and other commercially important fungi.<ref>{{cite journal |vauthors=Mello A, Ghignone S, Vizzini A, Sechi C, Ruiu P, Bonfante P |year=2006 |title=ITS primers for the identification of marketable boletes |journal=Journal of Biotechnology |volume=121 |issue=3 |pages=318–29 |doi=10.1016/j.jbiotec.2005.08.022 |pmid=16213623}}</ref><ref>{{cite journal |vauthors=Lian B, Zang JP, Hou WG, Yuan S, Smith DL |year=2008 |title=PCR-based sensitive detection of the edible fungus ''Boletus edulis'' from rDNA ITS sequences |journal=Electronic Journal of Biotechnology |volume=11 |issue=3 |pages=1–8 |doi=10.2225/vol11-issue3-fulltext-4 |doi-broken-date=2024-11-10 |issn=0717-3458|url=http://www.bioline.org.br/pdf?ej08040 |hdl=1807/48975 |hdl-access=free }}</ref>

Three divergent lineages found in Yunnan province in China that are commonly marketed and sold as ''B.&nbsp;edulis'' (and are actually more closely related to ''B.&nbsp;aereus'') were described in 2013 as ''[[Boletus bainiugan|B. bainiugan]]'', ''[[Boletus meiweiniuganjun|B. meiweiniuganjun]]'' and ''[[Boletus shiyong|B. shiyong]]''.<ref name="Dentinger 2013">{{cite journal|author=Dentinger B|date=12 October 2013|title=Nomenclatural novelties|journal=Index Fungorum|issue=29|page=1|issn=2049-2375|url=http://www.indexfungorum.org/Publications/Index%20Fungorum%20no.29.pdf}}</ref><ref name="Dentinger 2014">{{cite journal|vauthors=Dentinger B, Suz LM |date=2014|title=What's for dinner? Undescribed species of porcini in a commercial packet|journal=PeerJ |volume=2|issue=2:e570|pages=e570|doi=10.7717/peerj.570|pmid=25279259|pmc=4179395 |doi-access=free }}</ref> The classification has since been updated and expanded. All lineages are still members of ''Boletus'' sect. ''Boletus'', the sensu sticto "porcini clade" of the genus.<ref name=Cui2016>{{cite journal |last1=Cui |first1=Yang-Yang |last2=Feng |first2=Bang |last3=Wu |first3=Gang |last4=Xu |first4=Jianping |last5=Yang |first5=Zhu L. |title=Porcini mushrooms (Boletus sect. Boletus) from China |journal=Fungal Diversity |date=November 2016 |volume=81 |issue=1 |pages=189–212 |doi=10.1007/s13225-015-0336-7 |s2cid=12866685 |url=http://groups.kib.cas.cn/klpb/yzl/tnh_fblw/201509/P020150928547013572278.pdf}}</ref>

[[File:Boletus rex-veris 42967.jpg|thumb|left|''B. rex-veris''|alt=A group of three mushrooms with reddish-brown caps, bright yellow porous undersides, and thick white stipes. They are growing on the ground in soil covered with pine needles.]]

Western North America has several species closely related to ''B.&nbsp;edulis''. The white king bolete (''[[Boletus barrowsii|B.&nbsp;barrowsii]]''), found in parts of [[Colorado]], [[New Mexico]], [[Arizona]], and California (and possibly elsewhere), is named after its discoverer Chuck Barrows.<ref>{{cite web|url=http://botit.botany.wisc.edu/Toms_fungi/aug2004.html|access-date=2008-09-23|title=''Boletus barrowsii'', Chuck Barrows' bolete|author=Volk T.|date=August 2004|work=Tom Volk's Fungus of the Month|publisher=Department of Biology, University of Wisconsin-La Crosse|archive-url=https://web.archive.org/web/20081003220326/http://botit.botany.wisc.edu/toms_fungi/aug2004.html <!--Added by H3llBot-->|archive-date=2008-10-03}}</ref> It is lighter in colour than ''B.&nbsp;edulis'', having a cream-coloured cap with pink tones;<ref name=Miller2006>{{cite book |vauthors=Miller HR, Miller OK |title=North American Mushrooms: a Field Guide to Edible and Inedible Fungi |publisher=Falcon Guide |location=Guilford, Conn |year=2006 |page=392 |isbn=0-7627-3109-5 }}</ref> often [[mycorrhiza]]l with [[Ponderosa pine]], it tends to grow in areas where there is less rainfall. Some find its flavour as good as if not better than ''B.&nbsp;edulis''.<ref name=Evenson>{{cite book |title=Mushrooms of Colorado and the Southern Rocky Mountains |author=Evenson VS. |year=1997 |publisher=Westcliffe Publishers |location= Boulder, Colorado|isbn=978-1-56579-192-3 |page=157|url=https://books.google.com/books?id=EAeDeyqZLq0C&q=boletus%20edulis&pg=PA157|access-date=2009-10-20}}</ref> The California king bolete (''Boletus edulis var. grandedulis'') can reach massive proportions, and is distinguished from ''B.&nbsp;edulis'' by a mature pore surface that is brown to slightly reddish. The cap colour appears to be affected by the amount of light received during its development, and may range from white in young specimens grown under thick [[forest canopy|canopy]], to dark-brown, red-brown or yellow brown in those specimens receiving more light.<ref name=eb1>{{cite journal |author=Arora D. |year=2008 |title=California porcini: three new taxa, observations on their harvest, and the tragedy of no commons |journal=Economic Botany |volume=62 |issue=3 |pages=356–75 |url=http://www.davidarora.com/uploads/arora_california_porcini.pdf |doi=10.1007/s12231-008-9050-7 |s2cid=23176365 |access-date=2009-11-04 |archive-date=2012-03-12 |archive-url=https://web.archive.org/web/20120312213054/http://www.davidarora.com/uploads/arora_california_porcini.pdf }}</ref> The queen bolete (''[[Boletus regineus]]''), formerly considered a variety of ''B.&nbsp;aereus'', is also a choice edible. It is generally smaller than ''B.&nbsp;edulis'', and unlike that species, is typically found in [[mixed forest]]s.<ref name="urlCalifornia Fungi: Boletus regineus">{{cite web |url=http://www.mykoweb.com/CAF/species/Boletus_regineus.html |title=California Fungi: ''Boletus regineus'' |vauthors=Wood M, Stevens F |publisher=MykoWeb |access-date=2009-11-02}}</ref> The spring king bolete (''[[Boletus rex-veris]]''), formerly considered a variety of ''B.&nbsp;edulis'' or ''B.&nbsp;pinophilus'', is found throughout western North America. In contrast to ''B.&nbsp;edulis'', ''B.&nbsp;rex-veris'' tends to fruit in clusters, and, as its common name suggests, appears in the spring.<ref name="urlCalifornia Fungi: Boletus rex-veris">{{cite web |url=http://www.mykoweb.com/CAF/species/Boletus_rex-veris.html |title=California Fungi: ''Boletus rex-veris'' |vauthors=Wood M, Stevens F |publisher= MykoWeb|access-date=2009-11-03}}</ref> ''[[Boletus fibrillosus|B.&nbsp;fibrillosus]]'' is edible but considered inferior in taste.<ref>{{cite book|last1=Trudell|first1=Steve|url=https://books.google.com/books?id=WevHvt6Tr8kC|title=Mushrooms of the Pacific Northwest|last2=Ammirati|first2=Joe|publisher=Timber Press|year=2009|isbn=978-0-88192-935-5|series=Timber Press Field Guides|location=Portland, OR|page=217}}</ref>

==Habitat and distribution==
[[File:Boletus edulis 11.jpg|thumb|upright|In Lithuania|alt=A mushroom with a brown smooth cap the shape of a halved sphere, atop a thick, dirty white stipe. The mushroom is growing on a sloping patch of ground amongst moss, twigs and other forest debris; trees can be faintly seen in the background.]]

The fruit bodies of ''Boletus edulis'' can grow singly or in small clusters of two or three specimens. The mushroom's habitat consists of areas dominated by pine (''[[Pinus]]'' spp.), spruce (''[[Picea]]'' spp.), hemlock (''[[Tsuga]]'' spp.) and fir (''[[Abies]]'' spp.) trees, although other hosts include [[chestnut]], [[Chrysolepis|chinquapin]], [[beech]], ''[[Keteleeria]]'' spp., ''[[Lithocarpus]]'' spp., and [[oak]]. In California, porcini have been collected in a variety of forests, such as coastal forests, dry interior oak forests and [[savanna]]s and interior high-elevation [[Montane forest|montane]] [[mixed forest]]s,<ref name=Hall1998/> to an altitude of {{convert|3,500|m|ft|abbr=on}}.<ref name=Hall2003>{{cite book|vauthors=Hall IR, Stephenson SR, Buchanan PK, Yun W, Cole A |title=Edible and Poisonous Mushrooms of the World|url=https://archive.org/details/ediblepoisonousm00hall |url-access=limited |publisher=Timber Press|location=Portland, Oregon|year=2003|pages=[https://archive.org/details/ediblepoisonousm00hall/page/n224 224]–25|isbn=0-88192-586-1}}</ref> In northwestern Spain, they are common in [[scrubland]]s dominated by the [[Cistaceae|rock rose]] species ''[[Cistus ladanifer]]'' and ''Halimium lasianthum''.<ref>{{cite journal|vauthors=Oria-de-Rueda J, Martin-Pinto P, Olaizola J |year=2008 |title=Bolete productivity of cistaceous scrublands in northwestern Spain |journal=Economic Botany |volume=62 |issue=3|pages=323–30 |doi=10.1007/s12231-008-9031-x|s2cid=20095996 }}</ref> In [[Southern France|the Midi region of south-west France]], they are especially favoured and locally called ''cèpe de Bordeaux'' after the town from which they are traded to the north and abroad.<ref>{{cite book|first=Colin Duncan|last=Taylor|title=Menu from the Midi: A Gastronomic Journey through the South of France|year=2021|publisher=Matador |language=English| isbn= 978-1-80046-496-4}}</ref>

''Boletus edulis'' has a [[cosmopolitan distribution]], concentrated in cool-[[temperate]] to [[subtropical]] regions.<ref name=Hall1998/> It is common in Europe—from northern Scandinavia, south to the extremities of Greece and Italy—and North America, where its southern range extends as far south as Mexico.<ref name=Wang1995>{{cite journal |doi=10.1080/01140671.1995.9513892 |vauthors=Wang Y, Sinclair L, Hall IR, Cole AL |year=1995 |title=''Boletus edulis'' sensu lato: a new record for New Zealand|journal=New Zealand Journal of Crop and Horticultural Science |volume=23 |pages=227–31 |url=http://pdfserve.informaworld.com/915037__920077166.pdf |access-date=2009-12-06 |issue=2|doi-access=free }}</ref> It is well known from the [[Borgotaro]] area of [[Parma]], Italy, and has [[Protected designation of origin|PGI]] status there. The European distribution extends north to Scandinavia and south to southern Italy and Morocco.<ref name=Hall1998>{{cite journal |vauthors=Hall IR, Lyon AJ, Wang Y, Sinclair L |year=1998 |title=Ectomycorrhizal fungi with edible fruiting bodies 2. ''Boletus edulis'' |journal=Economic Botany |volume=52 |issue=1 |pages=44–56 |doi=10.1007/BF02861294|s2cid=20934023 }}</ref> In North America, it can be found from May to October inland<ref>{{Cite web |title=Seasonal Chart for Edible Mushrooms |url=https://www.centraloregonmushroomclub.com/Mushroom-Seasons.htm?m=102&s=866 |access-date=2024-03-31 |website=Central Oregon Mushroom Club |archive-date=2024-03-31 |archive-url=https://web.archive.org/web/20240331075937/https://www.centraloregonmushroomclub.com/Mushroom-Seasons.htm?m=102&s=866 |url-status=dead }}</ref> and August to January on the West Coast.<ref name="audu">{{Cite book |last=[[Audubon]] |title=Mushrooms of North America |publisher=[[Knopf]] |year=2023 |isbn=978-0-593-31998-7 |pages=327}}</ref> In China, the mushroom can be found from the northeastern [[Heilongjiang]] to the [[Yunnan–Guizhou Plateau]] and [[Tibet]].<ref name=Wang1995/> It has been recorded growing under ''Pinus'' and ''Tsuga'' in [[Sagarmatha National Park]] in Nepal,<ref>{{cite journal |vauthors=Giri A, Rana P |year=2007|title=Some Higher Fungi from Sagarmatha National Park (SNP) and its adjoining areas, Nepal|journal=Scientific World |volume=5 |issue=5 |pages=67–74 |doi=10.3126/sw.v5i5.2659|doi-access=free }}</ref> as well as in the Indian forests of [[Arunachal Pradesh]].<ref>{{cite journal |vauthors=Adhikary RK, Baruah P, Kalita P, Bordoloi D |year=1999 |title=Edible mushrooms growing in forests of Arunachal Pradesh |journal=Advances in Horticulture and Forestry |volume=6 |pages=119–23}}</ref> In West Asia, the species has been reported from the northwest forests of Iran.<ref>{{cite journal |author=Asef MR. |year=2008 |title=Macrofungi of Arasbaran 2. Boletes (families Boletaceae and Suillaceae) |journal=Rostaniha |volume=9 |issue=2 |pages=210–29 |url=http://www.sid.ir/fa/VEWSSID/J_pdf/50313873207.pdf |language=ar}}</ref>

===Cultivation===
Some steps have been made towards cultivating ''Boletus edulis'',<ref name="Wang2014">{{Citation |last1=Wang |first1=Yun |title=Recent Advances in Cultivation of Edible Mycorrhizal Mushrooms |date=2014 |url=https://www.researchgate.net/publication/270546094 |work=Mycorrhizal Fungi: Use in Sustainable Agriculture and Land Restoration |volume=41 |page=384 |editor-last=Solaiman |editor-first=Zakaria M. |place=Berlin, Heidelberg |publisher=Springer Berlin Heidelberg |doi=10.1007/978-3-662-45370-4_23 |isbn=978-3-662-45369-8 |access-date=2022-10-03 |last2=Chen |first2=Ying Long |editor2-last=Abbott |editor2-first=Lynette K. |editor3-last=Varma |editor3-first=Ajit}}</ref> including mycorrhization of [[Cistus ladanifer|rockrose]] shrubs enhanced by helper bacteria.<ref name="Mediavilla2015">{{Cite journal |last1=Mediavilla |first1=Olaya |last2=Olaizola |first2=Jaime |last3=Santos-del-Blanco |first3=Luis |last4=Oria-de-Rueda |first4=Juan Andrés |last5=Martín-Pinto |first5=Pablo |date=2015-07-26 |title=Mycorrhization between Cistus ladanifer L. and Boletus edulis Bull is enhanced by the mycorrhiza helper bacteria Pseudomonas fluorescens Migula |url=http://sostenible.palencia.uva.es/system/files/publicaciones/mediavilla_et_al._2015._mycorrhization_between_cistus_ladanifer_l._and_boletus_edulis.pdf |journal=Mycorrhiza |language=en |volume=26 |issue=2 |pages=161–168 |doi=10.1007/s00572-015-0657-0 |pmid=26208816 |s2cid=8967720 |issn=0940-6360}}</ref>

===Non-native introductions===
''Boletus edulis'' grows in some areas where it is not believed to be [[indigenous (ecology)|indigenous]]. It is often found underneath oak and [[Betula pendula|silver birch]] in [[Hagley Park, Christchurch|Hagley Park]] in central [[Christchurch]], New Zealand, where it is likely to have been [[introduced species|introduced]],<ref>{{cite journal |vauthors=Orlovich D, Stringer A, Yun W, Hall I, Prime G, Danell E, Weden C, Bulman S |year= 2004 |title = ''Boletus edulis'' Bull. Ex Fries in New Zealand|journal= Australasian Mycological Society Newsletter|volume=1 |issue=1 |page= 6}}</ref> probably on the roots of container-grown beech, birch, and oak in the mid-19th century—around the time exotic trees began to be planted in the Christchurch area.<ref name=Wang1995/> Similarly, it has been collected in [[Adelaide Hills]] region of Australia in association with three species of introduced trees.<ref name="Catcheside 2011">{{cite journal |vauthors=Catcheside PS, Catcheside DE |title=''Boletus edulis'' (Boletaceae), a new record for Australia |journal=Journal of the Adelaide Botanic Garden |year=2011 |volume=25 |pages=5–10 |url=http://www.environment.sa.gov.au/Knowledge_Bank/Science_research/State_Herbarium/Resources/Publications/Journal_of_the_Adelaide_Botanic_Gardens/Journal_search/25/1 |format=PDF |archive-url=https://web.archive.org/web/20140517151731/http://www.environment.sa.gov.au/Knowledge_Bank/Science_research/State_Herbarium/Resources/Publications/Journal_of_the_Adelaide_Botanic_Gardens/Journal_search/25/1 |archive-date=2014-05-17 }}</ref> It has been growing plentifully in association with pine forests in the southern [[KwaZulu-Natal Midlands]] in South Africa for more than 50 years and is believed to have been introduced with the import of pine trees.<ref>{{cite journal |author=Eicker A.|year=1990|title=Commercial mushroom production in South Africa |journal=Bulletin|issue=418 | publisher = Department of Agricultural Development|location =Pretoria}}</ref><ref>{{cite journal |vauthors=Marais LJ, Kotzé JM |year=1977|title=Notes on ectotrophic mycorrhizae of ''Pinus patula'' in South Africa|journal=South African Forestry Journal |volume=100|pages=61–71 |doi=10.1080/00382167.1977.9629436}}</ref> It also grows in pine plantations in neighboring Zimbabwe.<ref name=Masuka1996/>

==Ecology==
{{Multiple image|direction=vertical|image1=Pinus radiata HuckleberryHill1.jpg|image2=Amanita muscaria 3 vliegenzwammen op rij.jpg|width=200|caption1=''B. edulis'' is [[ectomycorrhiza]]l and may co-occur with ''Pinus radiata''|caption2=and ''[[Amanita muscaria]]''.|alt1=About half a dozen pine trees with upward-pointing branches 15 to 30 metres in height with green needles. The upper half of the background is blue sky.|alt2=A group of three mushrooms, ranging in size from small to large, with red caps dotted with white warts, and white stems. The largest of the three has a droopy skirt hanging from the upper portion of its stem. The mushrooms are growing in the ground, surrounded by fallen brown leaves, green grass, and a dark green bush in the background.}}

===Fruit body production===
Italian folklore holds that porcini sprout up at the time of the new moon;<ref name = "Carluccio03"/> research studies have tried to investigate more scientifically the factors that influence the production of fruit bodies. Although fruit bodies may appear any time from summer to autumn (June to November in the UK), their growth is known to be triggered by rainfall during warm periods of weather followed by frequent autumn rain with a drop in soil temperature.<ref name=Hall1998/> Above average rainfall may result in the rapid appearance of large numbers of boletes, in what is known in some circles as a "bolete year".<ref name=Nilper>{{cite book |vauthors=Nilson S, Persson O | year = 1977 | title = Fungi of Northern Europe 1: Larger Fungi (Excluding Gill-Fungi) | publisher = Penguin |location=Harmondsworth, England|isbn=0-14-063005-8|page=100}}</ref> A 2004 [[field study]] indicated that fruit body production is enhanced by an open and sunny wood habitat,<ref>{{cite journal |vauthors=Salerni E, Perini C |year=2004 |title=Experimental study for increasing productivity of ''Boletus edulis'' s.l. in Italy |journal=Forest Ecology and Management |volume=201 |issue=2–3 |pages=161–70|doi=10.1016/j.foreco.2004.06.027}}</ref> corroborating an earlier observation made in a Zimbabwean study;<ref name=Masuka1996>{{cite journal |author=Masuka AJ. |year=1996 |title=Dynamics of mushroom (''Boletus edulis'') production in pine plantations in Zimbabwe |journal= Journal of Applied Science in Southern Africa |volume=2 |issue=2 |pages=69–76 |doi=10.4314/jassa.v2i2.16877|url=http://opendocs.ids.ac.uk/opendocs/handle/123456789/8944 |url-access=subscription }}</ref> removal of the litter layer on the [[forest floor]] appeared to have a negative effect on fruit body production, but previous studies reported contradictory results.<ref>{{cite journal |vauthors=Baar J, Ter Braak CJ |year=1996 |title=Ectomycorrhizal sporocarp occurrence as affected by manipulation of litter and humus layers in Scots pine stands of different age |journal=Applied Soil Ecology |volume=4 |issue=1 |pages=61–73|doi= 10.1016/0929-1393(96)00097-2}}</ref><ref>{{cite journal |vauthors=Baar J, de Vries FW |year=1995 |title=Effects of manipulation of litter and humus layer on ectomycorrhizal colonization potential in Scots pine stands of different age |journal=Mycorrhiza |volume=5 |issue=4 |pages=267–72 |doi=10.1007/BF00204960 |s2cid=32618842 }}</ref> A Lithuanian study conducted in 2001 concluded that the maximal daily growth rate of the cap (about 21&nbsp;mm or 0.8&nbsp;in) occurred when the [[relative air humidity]] was the greatest, and the fruit bodies ceased growing when the air humidity dropped below 40%. Factors most likely to inhibit the appearance of fruit bodies included prolonged drought, inadequate air and soil humidity, sudden decreases of night air temperatures, and the appearance of the first [[frost]].<ref>{{cite journal |author=Kasparavicius, J. |year=2001 |title=Influence of climatic conditions on the growth of fruit bodies of ''Boletus edulis'' |journal=Botanica Lithuanica |volume=7 |issue=1 |pages=73–78 |issn=1392-1665}}</ref> Plots facing north tend to produce more mushrooms compared to equivalent plots facing south.<ref>{{cite journal |vauthors=Martín-Pinto P, Vaquerizo H, Peñalver F, Olaizola J, Oria-de-Rueda J |year=2006 |title=Early effects of a wildfire on the diversity and production of fungal communities in Mediterranean vegetation types dominated by ''Cistus ladanifer'' and ''Pinus pinaster'' in Spain |journal=Forest Ecology and Management |volume=225 |issue=1–3 |pages=296–305|doi=10.1016/j.foreco.2006.01.006}}</ref>

===Mycorrhizal associations===
''Boletus edulis'' is [[mycorrhiza]]l—it is in a [[Mutualism (biology)|mutualistic]] relationship with the roots of plants (hosts), in which the fungus exchanges [[nitrogen]] and other nutrients extracted from the environment for [[carbon fixation|fixed carbon]] from the host. Other benefits for the plant are evident: in the case of the [[Castanea mollissima|Chinese chestnut]], the formation of mycorrhizae with ''B.&nbsp;edulis'' increases the ability of plant seedlings to resist [[moisture stress|water stress]], and increases leaf [[succulent plants|succulence]], leaf area, and water-holding ability.<ref>{{cite journal |vauthors=Quan L, Lei ZP |year=2000 |title=A study on effect of ectomycorrhizae on promoting ''Castanea mollissima'' resistance to drought and its mechanism |journal=Forest Research |volume=13 |issue=3 |pages=249–56 |issn=1001-1498|language=zh}}</ref> The fungus forms a sheath of tissue around terminal, nutrient-absorbing root tips, often inducing a high degree of branching in the tips of the host, and penetrating into the root tissue, forming, to some mycologists, the defining feature of ectomycorrhizal relationships, a [[hartig net]].<ref name="ReferenceA">Smith, Sally; Read, David. Mycorrhizal Symbiosis. Academic press, 1996</ref>  The ectomycorrhizal fungi are then able to exchange nutrients with the plant, effectively expanding the root system of the host plant to the furthest reaches of the symbiont fungi.<ref name="ReferenceA"/> Compatible hosts may belong to multiple families of [[vascular plant]]s that are widely distributed throughout the Northern Hemisphere; according to one 1995 estimate, there are at least 30 host plant species distributed over more than 15 genera.<ref name=Wang1995/> Examples of mycorrhizal associates include [[Pinus massoniana|Chinese red pine]],<ref>{{cite journal |vauthors=Fu SC, Tan Q, Chen MJ, Shang XD, Cai LY, Zhang MY |year=2009 |title=Mycorrhizal synthesis involving ''Boletus edulis'' and ''Pinus massoniana''|journal= Acta Edulis Fungi |volume=16 |issue=1 |pages=31–41 |issn=1005-9873}}</ref> [[Pinus patula|Mexican weeping pine]],<ref>{{cite journal |vauthors=Gross E, Thomazini-Casagrande LI, Caetano FH |year=1998 |title=A scanning electron microscopy study of ectomycorrhizae on ''Pinus patula'' Schiede and Deppe |journal=Naturalia (Rio Claro) |volume=23 |issue=1 |pages=93–101 |issn=0101-1944 }}</ref> [[Scots pine]], [[Picea abies|Norway spruce]],<ref>{{cite journal |vauthors=Ceruti A, Tozzi M, Reitano G |year=1987–88 |title=Micorrize di sintesi tra ''Boletus edulis'', ''Pinus sylvestris'' e ''Picea excelsa''|trans-title=Mycorrhizal synthesis between ''Boletus edulis'', ''Pinus sylvestris'' and ''Picea excelsa''|journal=Allionia (Turin) |volume=28 |pages=117–24|issn=0065-6429|language=it}}</ref> [[Pseudotsuga menziesii|Coast Douglas-fir]],<ref>{{cite journal |author=Gobl F. |year=1977 |title=Mycorrhiza in Austrian Douglas fir stands |journal=Centralblatt für das Gesamte Forstwesen |volume=94 |issue=4 |pages=185–94|issn=0379-5292|language=de}}</ref> [[Pinus mugo|mountain pine]],<ref>{{cite journal |vauthors=Froidevaux L, Amiet R |year=1975 |title= Ecto mycorrhizae endo mycorrhizae of ''Pinus mugo'' plus ''Boletus edulis'' ssp ''edulis'' and ''Pinus cembra'' plus ''Suillus variegatus'' formed in pure culture |journal=European Journal of Forest Pathology |volume=5 |issue=1 |pages=57–61 |issn=0300-1237 |doi=10.1111/j.1439-0329.1975.tb00935.x}}</ref> and [[Pinus virginiana|Virginia pine]].<ref>{{cite journal |vauthors=Vozzo JA, Hackskaylo E |year=1961 |title=Mycorrhizal fungi on ''Pinus virginiana'' |journal=Mycologia |volume=53 |issue=5 |pages=538–39 |doi=10.2307/3756310 |jstor=3756310}}</ref> The fungus has also been shown to associate with [[Cistus ladanifer|gum rockrose]], a [[pioneer species|pioneer]] early stage shrub that is adapted for growth in degraded areas, such as burned forests.<ref name=Agueda2008/> These and other [[Cistus|rockrose]] species are ecologically important as fungal reservoirs, maintaining an inoculum of mycorrhizal fungi for trees that appear later in the [[Ecological succession|forest regrowth cycle]].<ref>{{cite journal |vauthors=Águeda B, Parladé J, de Miguel AM, Martínez-Peña F |year=2006 |title=Characterization and identification of field ectomycorrhizae of ''Boletus edulis'' and ''Cistus ladanifer'' |journal=Mycologia |volume=98 |issue=1 |pages=23–30 |doi=10.3852/mycologia.98.1.23 |pmid=16800301|hdl=10171/18758 |hdl-access=free }}</ref>

The mushroom has been noted to often co-occur with ''[[Amanita muscaria]]'' or ''[[Amanita rubescens|A.&nbsp;rubescens]]'', although it is unclear whether this is due to a biological association between the species, or because of similarities in growing season, habitat, and ecological requirements.<ref name=Hall1998/> An association has also been reported between ''B.&nbsp;edulis'' and ''[[Amanita excelsa var. spissa|Amanita excelsa]]'' on ''[[Pinus radiata]]'' ectomycorrhizae in New Zealand, suggesting that other fungi may influence the life cycle of porcini.<ref>{{cite journal |vauthors=Hall IR, Wang Y, Amicucci A |year=2003 |title=Cultivation of edible ectomycorrhizal mushrooms |journal=Trends in Biotechnology |volume=21 |issue=10|pages=433–38 |doi=10.1016/S0167-7799(03)00204-X|pmid=14512229}}</ref> A 2007 field study revealed little correlation between the abundance of fruit bodies and presence of its mycelia below ground, even when soil samples were taken from directly beneath the mushroom; the study concluded that the triggers leading to formation of mycorrhizae and production of the fruit bodies were more complex.<ref>{{cite journal |vauthors=Peintner U, Iotti M, Klotz P, Bonuso E, Zambonelli A |year=2007 |title=Soil fungal communities in a ''Castanea sativa'' (chestnut) forest producing large quantities of ''Boletus edulis sensu lato'' (porcini): where is the mycelium of porcini? |journal=Environmental Microbiology |volume=9 |issue=4 |pages=880–89 |doi=10.1111/j.1462-2920.2006.01208.x|pmid=17359260}}</ref>

===Heavy-metal contamination===
''Boletus edulis'' is known to be able to tolerate and even thrive on soil that is contaminated with toxic heavy metals, such as soil that might be found near metal [[smelters]]. The mushroom's resistance to heavy-[[metal toxicity]] is conferred by a biochemical called a [[phytochelatin]]—an [[oligopeptide]] whose production is induced after exposure to metal.<ref>{{cite journal |vauthors=Collin-Hansen C, Pedersen SA, Andersen RA, Steinnes E |year=2007 |title=First report of phytochelatins in a mushroom: induction of phytochelatins by metal exposure in ''Boletus edulis'' |journal=Mycologia |volume=99 |issue=2 |pages=161–74|doi=10.3852/mycologia.99.2.161 |pmid=17682769}}</ref> Phytochelatins are [[chelating]] agents, capable of forming [[coordination complex|multiple bonds]] with the metal; in this state, the metal cannot normally react with other elements or ions and is stored in a detoxified form in the mushroom tissue.{{Cn|date=December 2024}}

===Pests and predators===
The fruit bodies of ''B.&nbsp;edulis'' can be infected by the parasitic mould-like fungus ''[[Hypomyces chrysospermus]]'', known as the bolete eater, which manifests itself as a white, yellow, or reddish-brown cottony layer over the surface of the mushroom.<ref name="urlHypomyces chrysospermus (MushroomExpert.Com)">{{cite web |url=http://www.mushroomexpert.com/hypomyces_chrysospermus.html |title=''Hypomyces chrysospermus'' |author=Kuo M |work= MushroomExpert.Com|access-date=2009-11-02}}</ref> Some reported cases of [[Abdominal pain|stomach ache]] following consumption of dried porcini have been attributed to the presence of this mould on the fruit bodies.<ref>{{cite journal |vauthors=Lunghini D, Onofri S, Zucconi L |year=1984 |title= Some cases of intoxication probably caused by ''Sepedonium'' spp. infecting fruiting-bodies of some species of ''Boletus'' |journal=Micologia Italiana |volume=13 |issue=1 |pages=1/37–1/38 |issn=0390-0460|language=it}}</ref> The mushroom is also used as a food source by several species of mushroom flies,<ref name=Hall1998/> as well as other insects and their [[larva]]e.<ref>{{cite book |title=Fungus-Insect Relationships: Perspectives in Ecology and Evolution |author=Bruns TD. |veditors=Wheeler Q, Blackwell M |chapter=Insect mycophagy in the Boletales: fungivore diversity and the mushroom habitat |year=1984 |publisher=Columbia University Press |location=New York, NY |isbn=978-0-231-05695-3|pages=91–129}}</ref> An unidentified species of virus was reported to have infected specimens found in the Netherlands and in Italy; fruit bodies affected by the virus had relatively thick stems and small or no caps, leading to the name "little-cap disease".<ref>{{cite journal |vauthors=Huttinga H, Wichers HJ, Dieleman van Zaayen A |year=1975 |title=Filamentous and polyhedral virus-like particle in ''Boletus edulis'' |journal=Netherlands Journal of Plant Pathology |volume=81 |pages=102–106|doi=10.1007/BF01999860 |issue=3|s2cid=35794592 }}</ref><ref>{{cite journal |vauthors=Pisi A, Bellardi ME, Bernicchia A |year=1988 |title=Virus-like particles in ''Boletus edulis'' Bull. ex Fr. in Italy |journal=Phytopathologia Mediterranea |volume=27 |issue=2 |pages=115–18 |issn=0031-9465|url=http://www.mycologia.org/cgi/reprint/94/5/757.pdf|access-date=2009-11-03}}</ref>

''Boletus edulis'' is a food source for animals such as the [[banana slug]] ''(Ariolimax columbianus)'',<ref>{{cite journal |vauthors=Keller HW, Snell KL |year=2002 |title=Feeding activities of slugs on Myxomycetes and macrofungi |journal=Mycologia |volume=94 |issue=5 |pages=757–60 |doi= 10.2307/3761690 |jstor=3761690 |pmid=21156549}}</ref> the [[long-haired grass mouse]],<ref>{{cite journal |vauthors=Bozinovic F, Muñoz-Pedreros A |year=1995 |title=Nutritional ecology and digestive responses of an omnivorous-insectivorous rodent (''Abrothrix longipilis'') feeding on fungus |journal=Physiological Zoology |volume=68 |issue=3 |pages=474–89|doi=10.1086/physzool.68.3.30163780 |s2cid=87835970 }}</ref> the [[red squirrel]],<ref>{{cite journal |vauthors=Grönwall O, Pehrson Å |year=1984 |title=Nutrient content in fungi as a primary food of the Red Squirrel ''Sciurus vulgaris'' L |journal=Oecologia |volume=64 |issue=2 |pages=230–31 |doi= 10.1007/BF00376875|pmid=28312343 |bibcode=1984Oecol..64..230G |s2cid=28125328 }}</ref> and, as noted in one isolated report, the [[fox sparrow]].<ref>{{cite journal |vauthors=Schiller AM, Larson KW |year=2006 |title=Fox Sparrow foraging on a king bolete mushroom |journal=Northwestern Naturalist |volume=87 |issue=3 |page=252 |doi=10.1898/1051-1733(2006)87[252:FSFOAK]2.0.CO;2 |s2cid=86235892 |issn=1051-1733}}</ref>

==Culinary uses==
[[File:Porcini mushroom soup in breadbowl poland 2010.JPG|thumb|left|A porcini mushroom and noodle soup served in a bread bowl at a Polish restaurant]]
[[File:Penny bun sandwich at Nordiska Museet.jpg|thumb|left|A porcini mushroom sandwich in Stockholm, Sweden]]

''Boletus edulis'', as the species [[Botanical name#Components of plant names|epithet]] ''edulis'' ({{langx|la|edible}}) indicates, is an edible mushroom. Italian chef and restaurateur [[Antonio Carluccio]] has described it as representing "the wild mushroom ''par excellence''", and hails it as the most rewarding of all fungi in the kitchen for its taste and versatility.<ref name = "Carluccio03"/> Considered a choice edible, particularly in France, Germany, Poland and Italy,<ref name=Zeitl76/> it was widely written about by the Roman writers [[Pliny the Elder]] and Martial, although ranked below the esteemed ''[[Amanita caesarea]]''. When he was served ''suilli''{{efn|The term ''suilli'' was also thought to encompass the related ''[[Leccinum scabrum]]''.<ref>{{cite book|vauthors=Rolfe RT, Rolfe EW |title=The Romance of the Fungus World|publisher=Dover|location=New York|page=287|isbn=0-486-23105-4|year=1974}}</ref>}} instead of ''boleti'',<ref>{{cite book |vauthors=Brothwell DR, Brothwell P |title=Food in Antiquity: a Survey of the Diet of Early Peoples |year=1998 |orig-date=1969|page=92|publisher=The Johns Hopkins University Press|location=Baltimore, MD|isbn=0-8018-5740-6}}</ref> the disgruntled Martial wrote: {{blockquote|''sunt tibi boleti; fungos ego sumo suillos'' (Ep. iii. 60)<br />("You eat the choice boletus, I have mushrooms that swine grub up.")<ref>{{cite journal |author=Morford M. |year=1977 |title=Juvenal's Fifth Satire |journal=The American Journal of Philology |volume=98 |issue=3 |pages=219–45 |doi=10.2307/293772 |jstor=293772}}</ref>}}

The flavour of porcini has been described as nutty and slightly meaty, with a smooth, creamy texture, and a distinctive aroma reminiscent of [[sourdough]]. Young, small porcini are most appreciated, as the large ones often harbour [[maggot]]s (insect larvae), and become slimy, soft and less tasty with age. The fruit bodies are collected by holding the stipe near the base and twisting gently. Cutting the stipe with a knife may risk the part left behind rotting and the mycelium being destroyed. Peeling and washing are not recommended.<ref name="Carluccio03" /> The fruit bodies are highly [[decomposition|perishable]], due largely to the high water content (around 90%), the high level of [[enzyme]] activity, and the presence of a flora of microorganisms.<ref name=Jaworska2008>{{cite journal |vauthors=Jaworska G, Bernaś E |year=2008 |title=The effect of preliminary processing and period of storage on the quality of frozen ''Boletus edulis'' (Bull: Fr.) mushrooms |journal=Food Chemistry |volume=113 |issue=4 |pages=936–43 |doi=10.1016/j.foodchem.2008.08.023}}</ref> Caution should be exercised when collecting specimens from potentially polluted or [[Soil contamination|contaminated]] sites, as several studies have shown that the fruit bodies can [[bioaccumulation|bioaccumulate]] toxic heavy metals like [[mercury (element)|mercury]],<ref>{{cite journal |vauthors=Melgar MJ, Alonson J, Garcia MA |year=2009 |title=Mercury in edible mushrooms and underlying soil: Bioconcentration factors and toxicological risk |journal=Science of the Total Environment |volume=407 |issue=1 |pages=5328–34 |doi=10.1016/j.scitotenv.2009.07.001|pmid=19631362|bibcode=2009ScTEn.407.5328M }}</ref> [[cadmium]],<ref>{{cite journal |vauthors=Collin-Hansen C, Yttri KE, Andersen RA, Berthelsen BO, Steinnes E |year=2002 |title=Mushrooms from two metal-contaminated areas in Norway: occurrence of metals and metallothionein-like proteins |journal=Geochemistry: Exploration, Environment, Analysis |volume=2 |issue=2 |pages= 121–30|doi=10.1144/1467-787302-015|bibcode=2002GEEA....2..121C |s2cid=129662148 }}</ref> [[caesium]] and [[polonium]].<ref>{{cite journal |vauthors=Collin-Hansen C, Andersen RA, Steinnes E |year=2005 |title=Molecular defense systems are expressed in the king bolete (''Boletus edulis'') growing near metal smelters |journal=Mycologia |volume=97 |issue=5|pages=973–83|doi=10.3852/mycologia.97.5.973 |pmid=16596949 }}</ref><ref>{{cite journal |vauthors=Collin-Hansen C, Andersen RA, Steinnes E |year=2005 |title=Damage to DNA and lipids in ''Boletus edulis'' exposed to heavy metals |journal=Mycological Research |volume=109 |issue=12 |pages=1386–96 |doi= 10.1017/S0953756205004016|pmid=16353638}}</ref> Bioaccumulated metals or [[radionuclide|radioactive fission decay products]] are like chemical signatures: [[analytical chemistry|chemical]] and [[radiochemistry|radiochemical]] analysis can be used to identify the origin of imported specimens,<ref>{{cite journal |vauthors=Marzano FN, Bracchi PG, Pizzetti P |year=2001 |title=Radioactive and conventional pollutants accumulated by edible mushrooms (''Boletus'' sp.) are useful indicators of species origin |journal=Environmental Research |pmid=11237515 |volume=85 |issue=3 |pages=260–64 |doi=10.1006/enrs.2001.4233|bibcode=2001ER.....85..260M }}</ref> and for long-term [[radioecology|radioecological]] monitoring of polluted areas.<ref>{{cite journal |vauthors=Grodzinskaya AA, Berreck M, Haselwandter K, Wasser SP |year=2003 |title=Radiocesium contamination of wild-growing medicinal mushrooms in Ukraine |journal=International Journal of Medicinal Mushrooms |volume=5 |issue=1 |pages=61–86 |issn=1521-9437 |doi=10.1615/InterJMedicMush.v5.i1.90}}</ref>

Porcini are sold fresh in markets in summer and autumn in Europe and Russia, and dried or canned at other times of the year, and distributed worldwide to countries where they are not otherwise found.<ref name=Lamaison05>{{cite book |title=The Great Encyclopedia of Mushrooms |vauthors=Lamaison JL, Polese JM |year=2005 |publisher=Könemann |location=Koln, Germany |isbn=3-8331-1239-5|page=28}}</ref> They are eaten and enjoyed raw, sautéed with butter, ground into pasta, in soups, and in many other dishes. In France, they are used in recipes such as ''cèpes à la Bordelaise'', ''cèpe frits'' and ''cèpe aux tomates''.<ref>{{cite journal |author=Ramsbottom J. |year=1947 |title=Some edible fungi |journal=The British Medical Journal |volume=2 |issue=4250 |pages=304–305 |doi=10.1136/bmj.2.4520.304|pmid=20257565 |pmc=2055419 }}</ref> Porcini [[risotto]] is a traditional Italian autumn dish.<ref>Carluccio, p. 166.</ref> Porcini are a feature of many cuisines, including [[Provence|Provençal]],<ref>{{cite book |author=Olney R. |title= A Provençal Table|year=1995 |pages=31–32|publisher=Pavilion |location=London |isbn=1-85793-632-9}}</ref> and [[Vienna|Viennese]].<ref>{{cite book |author=Philpot R. |title= Viennese Cookery|year=1965 |pages=139–40|publisher=Hodder & Stoughton |location=London }}</ref> In [[Thailand]] they are used in soups and consumed blanched in salads.<ref name=Solomon>{{cite book |title=Charmaine Solomon's Encyclopedia of Asian Food |author=Solomon C. |year=1996 |publisher=William Heinemann Australia |location=Melbourne |isbn=0-85561-688-1|page=238}}</ref> Porcini can also be frozen, either while raw or after cooking in butter. The colour, aroma, and taste of porcini deteriorate noticeably after being frozen for four months. [[blanching (cooking)|Blanching]] (or soaking and blanching) as a processing step before freezing can extend the freezer life to 12 months.<ref name=Jaworska2008/> They are also one of the few species sold commercially as [[pickled mushrooms]].<ref>Carluccio, p. 99.</ref>

===Dried===
[[File:Pile of Porcini-2.jpg|thumb|alt=A heaped pile of dried sliced mushrooms on a large plate. A sign near the back of the plate reads "Fungo di Borgotaro I.G.P."; another sign at the front reads "Prezzo speciale di Fiera. 3 Etti 18,00". An electronic scale is partially visible on a table behind the mushrooms|A pile of dried porcini at the [[Borgotaro]] porcino festival in Italy]]

''Boletus edulis'' is well suited to drying—its flavour intensifies, it is easily reconstituted, and its resulting texture is pleasant.<ref>Carluccio, p. 96.</ref> Reconstitution is done by soaking in hot, but not boiling, water for about twenty minutes; the water used is infused with the mushroom aroma and it too can be used in subsequent cooking. Dried porcini have more protein than most other commonly consumed vegetables, apart from [[soybean]]s. Some of their protein is indigestible, though digestibility is improved with cooking.<ref name=Arora86>{{cite book |author=Arora D. |author-link=David Arora |title=Mushrooms Demystified: A Comprehensive Guide to the Fleshy Fungi |url=https://archive.org/details/arora-david-mushrooms-demystified-a-comprehensive-guide-to-the-fleshy-fungi-ten-speed-press-1986/page/530/mode/2up |publisher=[[Ten Speed Press]] |isbn=978-0-89815-170-1 |location=Berkeley, CA |year=1986 |orig-date=1979 |edition=2nd |pages=530-31}}</ref>

Like other boletes, porcini can be dried by being strung separately on twine and hung close to the ceiling of a kitchen. Alternatively, the mushrooms can be dried by cleaning with a brush (washing is not recommended), and then placing them in a wicker basket or [[bamboo steamer]] on top of a boiler or hot water tank.<ref name=Carluccio97>Carluccio, p. 97.</ref> Another method is drying in an oven at {{convert|25 to 30|C|F}} for two to three hours, then increasing the temperature to {{convert|50|C|F}} until crisp or brittle.<ref>{{cite book|vauthors=Gates L, Delong D |title=How to Dry Foods |publisher=HP Books |location=Los Angeles, California |year=1992 |page=61 |isbn=1-55788-050-6 |url=https://books.google.com/books?id=aSBfsPQP_MQC&q=cooking%20Boletus%20edulis&pg=PA61 |access-date=2009-10-06}}</ref> Once dry, they must be kept in an airtight container.<ref name=Carluccio97/> Importantly for commercial production, porcini retain their flavour after industrial preparation in a [[pressure cooker]] or after canning or bottling, and are thus useful for manufacturers of soups or stews. The addition of a few pieces of dried porcino can significantly add to flavour, and they are a major ingredient of the pasta sauce known as ''carrettiera'' (carter's sauce).<ref>{{cite book |author=Seed D. |title=The Top One Hundred Pasta Sauces |publisher=Ten Speed Press |location=Berkeley, California |year=1987 |page=25 |isbn=0-89815-232-1 |url=https://books.google.com/books?id=5JfdNVZlwA0C&q=cooking%20Boletus%20edulis&pg=PA25 |access-date=2010-11-06}}</ref> The drying process is known to induce the formation of various [[volatile organic compound|volatile substances]] that contribute to the mushroom's aroma. Chemical analysis has shown that the odour of the dried mushroom is a complex mixture of 53 volatile compounds.<ref name="pmid19845295">{{cite journal |vauthors=Misharina TA, Muhutdinova SM, Zharikova GG, Terenina MB, Krikunova NI |title=The composition of volatile components of cepe (''Boletus edulis'') and oyster mushrooms (''Pleurotus ostreatus'') |journal=Applied Biochemistry and Microbiology |volume=45 |issue=2 |pages=187–93 |year=2009 |pmid=19382709|doi=10.1134/S0003683809020124|s2cid=21525680 }}</ref>

===Commercial harvest===
[[File:Steinpilz 2006 08 3.jpg|thumb|alt=Approximately two dozen brown-capped, white or light-brown stemmed mushrooms of various sizes in a brown bowl.|Porcini can vary considerably in size.]]

A 1998 estimate suggested that the total annual worldwide consumption of ''Boletus edulis'' and closely related species (''B.&nbsp;aereus'', ''B.&nbsp;pinophilus'', and ''B.&nbsp;reticulatus'') was between 20,000 and 100,000 tons.<ref name=Hall1998/> Approximately 2,700&nbsp;tonnes (3,000&nbsp;[[Short ton|tons]]) were sold in France, Italy and Germany in 1988, according to official figures. The true amount consumed far exceeds this, as the official sales figures did not account for informal sales or consumption by collectors.<ref name=Hall2003/> They are widely exported and sold in dried form, reaching countries where they do not occur naturally, such as Australia and New Zealand. The autonomous community of [[Castile and León]] in Spain produces 7,700&nbsp;tonnes (8,500&nbsp;tons) annually.<ref name=Agueda2008>{{cite journal |vauthors=Agueda B, Parlade J, Fernandez-Toiran LM, Cisneros O, de Miguel AM, Modrego MP, Martinez-Pena F, Pera J |year=2008 |title=Mycorrhizal synthesis between ''Boletus edulis'' species complex and rockroses (''Cistus'' sp.) |journal=Mycorrhiza |pmid=18695982 |volume=18 |issue=8 |pages=443–49 |doi=10.1007/s00572-008-0192-3|s2cid=11233267 }}</ref> In autumn, the price of porcini in the Northern Hemisphere typically ranges between $20 and $80&nbsp;per kilogram, although in New York in 1997 the wholesale price rose to more than $200 per kilogram due to scarcity.<ref name=Hall2003/>

In the vicinity of [[Borgo Val di Taro|Borgotaro]] in the [[Province of Parma]] of northern Italy, the four species ''Boletus edulis'', ''B.&nbsp;aereus'', ''B.&nbsp;aestivalis'' and ''B.&nbsp;pinophilus'' have been recognised for their superior taste and officially termed ''Fungo di Borgotaro''. Here these mushrooms have been collected for centuries and exported commercially. Owing to the globalisation of the mushroom trade most of the porcini commercially available in Italy or exported by Italy no longer originate there. Porcini and other mushrooms are also imported into Italy from various locations, especially China and eastern European countries; these are then often re-exported under the "Italian porcini" label.<ref>{{cite journal |vauthors=Sitta N, Floriani M |year=2008 |title=Nationalization and globalization trends in the wild mushroom commerce of Italy with emphasis on porcini (''Boletus edulis'' and allied species) |journal=Economic Botany |volume=62 |issue=3 |pages=307–22 |doi=10.1007/s12231-008-9037-4|s2cid=44274570 }}</ref><ref name=Boa2004>{{cite book |author= Boa E. |title=Wild Edible Fungi: A Global Overview of Their Use and Importance to People (Non-Wood Forest Products) |publisher=Food & Agriculture Organization of the UN |location=Rome, Italy |year=2004 |pages=96–97 |isbn=92-5-105157-7|url=https://books.google.com/books?id=Zd2NlcNZgvcC&q=boletus%20edulis&pg=PA97|access-date=2009-10-30}}</ref>

In Italy the disconnect with local production has had an adverse effect on quality; for example in the 1990s some of the dried porcino mushrooms exported to Italy from China contained species of genus ''[[Tylopilus]]'', which are rather similar in appearance and when dried are difficult for both mushroom labourers and mycologists alike to distinguish from ''Boletus''. ''Tylopilus'' species typically have a very bitter taste, which is imparted to the flavour of the porcini with which they are mixed.<ref>{{cite journal |author=Sitta N. |year=2000 |title=Presence of ''Tylopilus'' into dried "Porcini" mushrooms from China |journal=Micologia Italiana |volume=29 |issue=1 |pages=96–99 |issn=0390-0460|language=it}}</ref>

After the [[revolutions of 1989|fall of the Iron Curtain]] and the subsequent reduction of economic and political barriers, central and eastern European countries with local mushroom harvesting traditions, such as Albania, Bulgaria, Macedonia, Romania, Serbia and Slovenia, developed into exporters of porcini, concentrating primarily on the Italian market.<ref name=Boa2004/> Porcini and other wild fungi from these countries are also destined for France, Germany and other western European markets, where demand for them exists but collection on a commercial scale does not.<ref name=Boa2004/> Picking ''B.&nbsp;edulis'' has become an annual seasonal income earner and pastime in countries like [[Bulgaria]], especially for many [[Romani people|Roma]] communities and the [[unemployment|unemployed]].<ref name=belogradchik>{{cite web |url=http://www.belogradchik.info/1/content/view/390/2/lang,bg/ |language=bg |title=''По 1 тон гъби на ден се предават в изкупвателните пунктове в Белоградчик'' |trans-title=One ton of mushrooms a day are being submitted to purchasing stations in Belogradchik |author=Focus Information Agency, Bulgaria |work=Belogradchik.info |access-date=2009-11-02 |archive-url=https://web.archive.org/web/20110721185827/http://www.belogradchik.info/1/content/view/390/2/lang%2Cbg/ |archive-date=2011-07-21 }}</ref> A lack of control of the harvest has led to heavy exploitation of the mushroom resource.<ref name=worldwildlife>{{cite web |url=http://www.worldwildlife.org/bsp/publications/europe/bulgaria/bulgaria1.html |title=The Macromycetes Fungi of Bulgaria |vauthors=Drumeva M, Gyosheva M |work= World Wildlife Fund|access-date=2009-11-27}}</ref>

Like many other strictly mycorrhizal fungi, ''B.&nbsp;edulis'' has eluded cultivation attempts for years.<ref name=Arora86/><ref>{{cite book |vauthors=Chang ST, Miles PG |title=Mushrooms: Cultivation, Nutritional Value, Medicinal Effect, and Environmental Impact|url=https://archive.org/details/mushroomscultiva00mile |url-access=limited |edition=2nd |year=2004|publisher=CRC Press |location= Boca Raton, Florida|isbn=0-8493-1043-1|page=[https://archive.org/details/mushroomscultiva00mile/page/n155 131]}}</ref><ref name="Wang2014" /> The results of some studies suggest that unknown components of the soil microflora might be required for ''B.&nbsp;edulis'' to establish a mycorrhizal relationship with the host plant.<ref>{{cite journal |author=Veselkov IM. |year=1975 |title=Artificial propagation of ''Boletus edulis'' in forests |journal=Растительньіе Ресурсы России|volume=11 |pages= 574–78}}</ref><ref>{{cite journal |vauthors=Ceruti A, Tozzi M, Reitano G |year=1988 |title=Micorize di sintesi tra ''Boletus edulis'', ''Pinus sylvestris'' e ''Picea excelsa'' |journal=Allionia (Turin)|volume=28 |pages= 117–24|language=it}}</ref><ref>{{cite book |vauthors=Fitter AH, Garbaye J |year=1994 |chapter=Interaction between mycorrhizal fungi and other organisms|title=Management of Mycorrhizas in Agriculture, Horticulture and Forestry |veditors=Robson AD, Abbott LK, Malajczuk N |isbn=978-0-7923-2700-4 |publisher=Kluwer Academic Publishers |location=Dordrecht, Netherlands}}</ref> Successful attempts at cultivating ''B.&nbsp;edulis'' have been made by Spanish scientists by mycorrhization of ''Cistus'' species,<ref name="Wang2014" /> with [[Pseudomonas fluorescens|''Pseudomonas&nbsp;fluorescens'']] bacteria helping the mycorrhiza.<ref name="Mediavilla2015" />

{{nutritionalvalue
| name=''Boletus edulis'', fresh<ref name=Caglarlrmak2002>Nutritional values are based on [[food chemistry|chemical analysis]] of Turkish specimens, conducted by Çaglarlrmak and colleagues at the Agricultural Faculty, Food Engineering Department, [[Gaziosmanpașa University]]. Source: {{cite journal |vauthors=Çaglarlrmak N, Ünal K, Ötles S |year=2001 |title=Nutritional value of edible wild mushrooms collected from the Black Sea region of Turkey |journal=Micologia Aplicada International |volume= 14|issue=1 |pages=1–5 |url=http://www.redalyc.org/pdf/685/68514101.pdf}}</ref>
| kJ=342.4
| protein=7.39&nbsp;g
| fat=1.70&nbsp;g
| carbs=9.23&nbsp;g
| iron_mg=0.739
| calcium_mg=1.195
| copper_mg=0.786
| phosphorus_mg=22.26
| potassium_mg=203.3
| zinc_mg=4.172
| vitC_mg=4.21
| pantothenic_mg=2.64
| vitB6_mg=0.051
| folate_ug=290
| thiamin_mg=0.105
| riboflavin_mg=0.092
| niacin_mg=6.07
| source_usda=1
}}

== Nutrition==
''Boletus edulis'' mushrooms are 9% [[carbohydrate]]s, 3% fat, and 7% [[protein]] (table). Fresh mushrooms consist of over 80% moisture,<ref name=Ouzouni2006>{{cite journal |vauthors=Ouzouni PK, Riganakos KA |year=2006 |title=Nutritional value and metal content profile of Greek wild edible fungi |journal=Acta Alimentaria |volume=36 |issue=1 |pages=99–110 |doi=10.1556/AAlim.36.2007.1.11}}</ref> although reported values tend to differ somewhat as moisture content can be affected by environmental temperature and [[relative humidity]] during growth and storage.<ref>{{cite book |title=The Biology and Cultivation of Edible Mushrooms |vauthors=Crisan EV, Sands A |year=1978|veditors=Chang ST, Hayes WA |chapter=Nutritional value |publisher=Academic Press |location=New York |isbn=978-0-12-168050-3|pages=727–93}}</ref> The carbohydrate component contains the [[monosaccharide]]s [[glucose]], [[mannitol]] and α,α-[[trehalose]], the [[polysaccharide]] [[glycogen]], and the water-insoluble structural polysaccharide [[chitin]], which accounts for up to 80–90% of dry matter in mushroom [[cell wall]]s. Chitin, [[hemicellulose]], and [[pectin]]-like carbohydrates—all indigestible by humans—contribute to the high proportion of insoluble fibre in ''B.&nbsp;edulis''.<ref name=Kalac2009>{{cite journal |author=Kalač P. |year=2009 |title=Chemical composition and nutritional value of European species of wild growing mushrooms: a review |journal=Food Chemistry |volume=113 |issue=1 |pages=9–16 |doi=10.1016/j.foodchem.2008.07.077}}</ref>

The total [[lipid]], or crude fat, content makes up 3% of the dry matter of the mushroom. The proportion of [[fatty acid]]s (expressed as a % of total fatty acids) are: [[linoleic acid]] 42%, [[oleic acid]] 36%, [[palmitic acid]] 10%, and [[stearic acid]] 3%.<ref>{{cite journal |vauthors=Pedneault K, Angers P, Gosselin A, Tweddell RJ |year=2006 |title=Fatty acid composition of lipids from mushrooms belonging to the family Boletaceae |journal=Mycological Research |volume=110|pages=1179–83 |doi=10.1016/j.mycres.2006.05.006 |pmid=16959482 |issue=Pt 10}}</ref>

A comparative study of the [[amino acid]] composition of eleven Portuguese wild edible mushroom species showed ''Boletus edulis'' to have the highest total amino acid content.<ref name=Ribeiro2008b>{{cite journal |vauthors=Ribeiro B, Andrade PB, Silva BM, Baptista P, Seabra RM, Valento P |year=2008 |title=Comparative study on free amino acid composition of wild edible mushroom species |journal=Journal of Agricultural and Food Chemistry |volume=56 |issue=22 |pages=10973–79 |doi=10.1021/jf802076p |pmid=18942845}}</ref><ref>{{cite journal |vauthors=Tsai SY, Tsai HL, Mau JL |year=2008 |title=Non-volatile taste components of ''Agaricus blazei'', ''Agrocybe cylindracea'' and ''Boletus edulis''|journal=Food Chemistry |volume=107 |issue=3 |pages=977–83 |doi=10.1016/j.foodchem.2007.07.080}}</ref>

''B. edulis'' mushrooms are rich in the [[mineral (nutrient)|dietary minerals]], [[sodium]], iron, [[calcium]], and [[magnesium]], with amounts varying according to the mushroom component and to soil composition in the geographic region of China where they were sampled.<ref name=Kalac2009/><ref name="Su">{{cite journal | last1=Su | first1=Jiuyan | last2=Zhang | first2=Ji | last3=Li | first3=Jieqing | last4=Li | first4=Tao | last5=Liu | first5=Honggao | last6=Wang | first6=Yuanzhong | title=Determination of mineral contents of wild ''Boletus edulis'' mushroom and its edible safety assessment | journal=Journal of Environmental Science and Health, Part B | volume=53 | issue=7 | date=6 April 2018 | issn=0360-1234 | doi=10.1080/03601234.2018.1455361 | pages=454–463|pmid=29624491| s2cid=4665228 }}</ref> They also have high content of [[B vitamins]] and [[tocopherol]]s.<ref name="Jaworska">{{cite journal | last1=Jaworska | first1=Grażyna | last2=Pogoń | first2=Krystyna | last3=Skrzypczak | first3=Aleksandra | last4=Bernaś | first4=Emilia | title=Composition and antioxidant properties of wild mushrooms Boletus edulis and Xerocomus badius prepared for consumption | journal=Journal of Food Science and Technology | volume=52 | issue=12 | date=12 July 2015 | issn=0022-1155 | doi=10.1007/s13197-015-1933-x | pages=7944–7953|pmid=26604366|pmc=4648917}}</ref> ''B.&nbsp;edulis'' contains appreciable amounts of [[selenium]], a [[trace mineral]],<ref>{{cite journal |author=Falandysz J. |year=2008 |title= Selenium in edible mushrooms |journal= Journal of Environmental Science and Health, Part C|volume=26 |issue=3 |pages=256–99|pmid= 18781538 |doi=10.1080/10590500802350086|s2cid=205722725 |url=https://zenodo.org/record/918325 }}</ref> although the [[bioavailability]] of mushroom-derived selenium is low.<ref>{{cite journal |author=Mutanen M. |year=1986 |title= Bioavailability of selenium in mushrooms |journal=International Journal for Vitamin and Nutrition Research |volume=56 |issue=3 |pages=297–301|pmid=3781756}}</ref>

== Phytochemicals and research==
[[File:Phytochelatin.svg|thumb|Phytochelatins give ''B. edulis'' resistance to toxic heavy metals like [[cadmium]].|alt=Skeletal formula depicting the amino acids cysteine and glycine joined in a peptide bond, with free carboxy and amino groups at either end of the peptide chain. Parentheses around the peptide bond indicate a variable number of amino acids are involved.]]

''Boletus edulis'' fruit bodies contain diverse [[phytochemical]]s, including 500&nbsp;mg of [[ergosterol]] per 100&nbsp;g of dried mushroom,<ref name=Mattilla2002>{{cite journal |vauthors=Mattila P, Lampi AM, Ronkainen R, Toivo J, Piironen V |year=2002 |title=Sterol and vitamin D<sub>2</sub> contents in some wild and cultivated mushrooms |journal=Food Chemistry |volume=76 |issue=3 |pages=293–98|doi=10.1016/S0308-8146(01)00275-8}}</ref> and [[ergothioneine]].<ref>{{cite journal |vauthors=Ey J, Schömig E, Taubert D |title=Dietary sources and antioxidant effects of ergothioneine |journal=Journal of Agricultural and Food Chemistry |volume=55 |issue=16 |pages=6466–74 |year=2007 |pmid=17616140 |doi=10.1021/jf071328f}}</ref> The fruit bodies contain numerous [[polyphenol]]s, especially a high content of [[rosmarinic acid]],<ref name="Vamanu">{{cite journal | last1=Vamanu | first1=Emanuel | last2=Nita | first2=Sultana | title=Antioxidant capacity and the correlation with major phenolic compounds, anthocyanin, and tocopherol content in various extracts from the wild edible ''Boletus edulis'' mushroom | journal=BioMed Research International | volume=2013 | year=2013 | issn=2314-6133 | doi=10.1155/2013/313905 | pages=1–11|pmid=23509707|pmc=3591155| doi-access=free }}</ref> and [[organic acid]]s (such as [[oxalic acid|oxalic]], [[citric acid|citric]], [[malic acid|malic]], [[succinic acid|succinic]] and [[fumaric acid]]s),<ref>{{cite journal |vauthors=Shu-Yao T, Hui-Li T, Jeng-Leun Mau LW |title=Antioxidant properties of ''Agaricus blazei'', ''Agrocybe cylindracea'', and ''Boletus edulis'' |journal=Food Science and Technology |volume=40 |issue=8 |year=2007 |pages=1392–1402 |doi=10.1016/j.lwt.2006.10.001}}</ref> and [[alkaloid]]s.<ref>{{cite journal |author1=Ribeiroa B |author2=Lopesa R |author3=Andradea PB |author4=Seabraa RM |author5=Gonçalvesa, Baptistab P |author6=Quelhasa I |author7=Valentão P. |year=2008 |title=Comparative study of phytochemicals and antioxidant potential of wild edible mushroom caps and stipes |journal=Food Chemistry |volume=110 |issue=1 |pages=47–56 |doi=10.1016/j.foodchem.2008.01.054|pmid=26050164 |url=https://bibliotecadigital.ipb.pt/bitstream/10198/4404/1/18.pdf |hdl=10198/4404 |hdl-access=free }}</ref>

===Aroma===
[[Odor|Aroma]] compounds giving ''B. edulis'' mushrooms their characteristic fragrance include some 100 components, such as [[ester]]s and [[fatty acid]]s.<ref name="csoka">{{cite journal | last1=Csóka | first1=Mariann | last2=Geosel | first2=Andras | last3=Amtmann | first3=Maria | last4=Korany | first4=Kornel | title=Volatile Composition of Some Cultivated and Wild Culinary-Medicinal Mushrooms from Hungary | journal=International Journal of Medicinal Mushrooms | volume=19 | issue=5 | year=2017 | issn=1521-9437 | doi=10.1615/intjmedmushrooms.v19.i5.50 | pages=433–443|pmid=28845772}}</ref> In a study of aroma compounds, [[1-octen-3-one]] was the most prevalent chemical detected in raw mushrooms, with [[pyrazine]]s having increased aroma effect and elevated content after drying.<ref name="Zhang">{{cite journal | last1=Zhang | first1=Huiying | last2=Pu | first2=Dandan | last3=Sun | first3=Baoguo | last4=Ren | first4=Fazheng | last5=Zhang | first5=Yuyu | last6=Chen | first6=Haitao | title=Characterization and comparison of key aroma compounds in raw and dry porcini mushroom ( Boletus edulis ) by aroma extract dilution analysis, quantitation and aroma recombination experiments | journal=Food Chemistry | volume=258 | year=2018 | issn=0308-8146 | doi=10.1016/j.foodchem.2018.03.056 | pages=260–268|pmid= 29655732| s2cid=4890378 }}</ref>

== In human culture ==

In 2023, with the signing of bill H.B. 92, ''Boletus edulis'' became the [[List of U.S. state mushrooms|state mushroom]] of Utah.<ref>{{Cite web|url=https://le.utah.gov/~2023/bills/static/HB0092.html|title=H.B. 92 State Mushroom Designation|website=Utah.gov |publisher=Utah State Legislature |access-date=2 April 2025}}</ref>

==See also==
*[[List of Boletus species|List of ''Boletus'' species]]
*[[List of North American boletes]]

==References==
'''Footnotes'''
{{Notelist}}

'''Citations'''
{{Reflist}}

===Cited texts===
* {{cite book|author=Carluccio, A.|author-link=Antonio Carluccio|year= 2003 |title= The Complete Mushroom Book|publisher = Quadrille |location=London |isbn=978-1-84400-040-1}}
* {{Commons-inline}}
* {{Wikispecies-inline}}

{{Taxonbar|from=Q19740}}

[[Category:Boletus|edulis]]
[[Category:Fungi described in 1782]]
[[Category:Fungi of Africa]]
[[Category:Fungi of Asia]]
[[Category:Fungi of Europe]]
[[Category:Fungi of New Zealand]]
[[Category:Fungi of North America]]
[[Category:Edible fungi]]
[[Category:Italian products with protected designation of origin]]
[[Category:Fungi of Western Asia]]
[[Category:Taxa named by Jean Baptiste François Pierre Bulliard]]
[[Category:Fungus species]]
[[Category:Fungi used for fiber dyes]]