''Boletus edulis'' (English: cep, penny bun, porcino or porcini) is a

basidiomycete Basidiomycota () is one of two large divisions that, together with the Ascomycota, constitute the subkingdom Dikarya (often referred to as the "higher fungi") within the kingdom Fungi. Members are known as basidiomycetes. More specifically, Basi ...

fungus, and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

of the genus ''

Boletus ''Boletus'' is a genus of mushroom-producing fungi, comprising over 100 species. The genus ''Boletus'' was originally broadly defined and described by Carl Linnaeus in 1753, essentially containing all fungi with hymenial pores instead of ...

''. Widely distributed in the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

across Europe, Asia, and North America, it does not occur naturally in the Southern Hemisphere, although it has been introduced to southern Africa, Australia, New Zealand, and Brazil. Several closely related European mushrooms formerly thought to be

varieties Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

forms Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens. Form also refers to: *Form (document), a document (printed or electronic) with spaces in which to write or enter data * ...

of ''B. edulis'' have been shown using

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analysis to be distinct species, and others previously classed as separate species are

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organ ...

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. The fungus grows in

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, aft ...

and

coniferous forest Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All exta ...

s and tree

plantation A plantation is an agricultural estate, generally centered on a plantation house, meant for farming that specializes in cash crops, usually mainly planted with a single crop, with perhaps ancillary areas for vegetables for eating and so on. The ...

s, forming

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

ectomycorrhizal An ectomycorrhiza (from Greek ἐκτός ', "outside", μύκης ', "fungus", and ῥίζα ', "root"; pl. ectomycorrhizas or ectomycorrhizae, abbreviated EcM) is a form of symbiotic relationship that occurs between a fungal symbiont, or mycobi ...

associations with living trees by enveloping the tree's underground roots with sheaths of fungal tissue. The fungus produces

spore In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

-bearing

fruit bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life cyc ...

above ground in summer and autumn. The fruit body has a large brown

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

which on occasion can reach , rarely in diameter and in weight. Like other

bolete {{refimprove, date=July 2020 A bolete is a type of mushroom, or fungal fruiting body. It can be identified thanks to a unique mushroom cap. The cap is clearly different from the stem. On the underside of the cap there is usually a spongy surf ...

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. edulis'' fruit body is whitish when young, but ages to a greenish-yellow. The stout stipe, or stem, is white or yellowish in colour, up to , rarely tall and thick, and partially covered with a raised network pattern, or reticulations. Prized as an ingredient in various culinary dishes, ''B. edulis'' is an

edible mushroom Edible mushrooms are the fleshy and edible fruit bodies of several species of macrofungi (fungi which bear fruiting structures that are large enough to be seen with the naked eye). They can appear either below ground (hypogeous) or above ground ...

held in high regard in many cuisines, and is commonly prepared and eaten in

soups Soup is a primarily liquid food, generally served warm or hot (but may be cool or cold), that is made by combining ingredients of meat or vegetables with stock, milk, or water. Hot soups are additionally characterized by boiling solid ingre ...

pasta Pasta (, ; ) is a type of food typically made from an unleavened dough of wheat flour mixed with water or eggs, and formed into sheets or other shapes, then cooked by boiling or baking. Rice flour, or legumes such as beans or lentils, are som ...

, or

risotto Risotto (, , from meaning "rice") is a northern Italian rice dish cooked with broth until it reaches a creamy consistency. The broth can be derived from meat, fish, or vegetables. Many types of risotto contain butter, onion, white wine, and Par ...

. The mushroom is low in

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers spec ...

and digestible

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...

s, and high in

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

vitamin A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an Nutrient#Essential nutrients, essential micronutrient that an organism needs in small quantities for the proper functioning of its ...

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

s and

dietary fibre Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by th ...

. Although it is sold commercially, it is very difficult to cultivate. Available fresh in

autumn Autumn, also known as fall in American English and Canadian English, is one of the four temperate seasons on Earth. Outside the tropics, autumn marks the transition from summer to winter, in September ( Northern Hemisphere) or March ( Sou ...

throughout

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

and

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

, it is most often dried, packaged, and distributed worldwide. It keeps its flavour after drying, and it is then reconstituted and used in

cooking Cooking, cookery, or culinary arts is the art, science and craft of using heat to Outline of food preparation, prepare food for consumption. Cooking techniques and ingredients vary widely, from grilling food over an open fire to using electric ...

. ''B. edulis'' is one of the few fungi sold

pickled Pickling is the process of preserving or extending the shelf life of food by either anaerobic fermentation in brine or immersion in vinegar. The pickling procedure typically affects the food's texture and flavor. The resulting food is called ...

Taxonomy

''Boletus edulis'' was first described in 1782 by the French botanist Pierre Bulliard and still bears its original name. The starting date of fungal

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

had been set as January 1, 1821, to coincide with the date of the works of the 'father of mycology', Swedish naturalist

Elias Magnus Fries Elias Magnus Fries (15 August 1794 – 8 February 1878) was a Swedish mycologist and botanist. Career Fries was born at Femsjö (Hylte Municipality), Småland, the son of the pastor there. He attended school in Växjö. He acquired ...

, 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 The ''International Code of Nomenclature for algae, fungi, and plants'' (ICN) is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "trad ...

set the starting date at May 1, 1753, the date of publication of

Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

' work, the ''

Species Plantarum ' (Latin for "The Species of Plants") is a book by Carl Linnaeus, originally published in 1753, which lists every species of plant known at the time, classified into genera. It is the first work to consistently apply binomial names and was the ...

''. Hence, the name no longer requires the ratification of Fries' authority. Early alternate names include ''Boletus solidus'' by English naturalist

James Sowerby James Sowerby (21 March 1757 – 25 October 1822) was an English naturalist, illustrator and mineralogist. Contributions to published works, such as ''A Specimen of the Botany of New Holland'' or ''English Botany'', include his detailed and app ...

in 1809, and Gray's ''Leccinum edule''. Gray's transfer of the species to ''Leccinum'' was later determined to be inconsistent with the rules of botanical

nomenclature Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. The principles of naming vary from the relatively informal naming conventions, conventions of everyday speech to the i ...

, and he apparently was unfamiliar with the earlier works of Fries when he published his arrangement of bolete species. ''Boletus edulis'' is the

of the genus ''

''. In

Rolf Singer Rolf Singer (June 23, 1906 – January 18, 1994) was a Germany, German-born mycologist and one of the most important Taxonomy (biology), taxonomists of gilled mushrooms (agarics) in the 20th century. After receiving his Ph.D. at the University ...

classification Classification is a process related to categorization, the process in which ideas and objects are recognized, differentiated and understood. Classification is the grouping of related facts into classes. It may also refer to: Business, organizat ...

of the

Agaricales The fungal order Agaricales, also known as gilled mushrooms (for their distinctive gills) or euagarics, contains some of the most familiar types of mushrooms. The order has 33 extant families, 413 genera, and over 13,000 described species, alo ...

mushrooms, it is also the type species of

section Section, Sectioning or Sectioned may refer to: Arts, entertainment and media * Section (music), a complete, but not independent, musical idea * Section (typography), a subdivision, especially of a chapter, in books and documents ** Section sign ...

''Boletus'', a grouping of about 30 related boletes united by several characteristics: a mild-tasting, white

flesh Flesh is any aggregation of soft tissues of an organism. Various multicellular organisms have soft tissues that may be called "flesh". In mammals, including humans, ''flesh'' encompasses muscle Skeletal muscles (commonly referred to as mu ...

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 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing pinkish-tan spore print. A 3.5-centimeter ...

; white tubes that later become yellowish then greenish, which initially appear to be stuffed with cotton; and

cystidia A cystidium (plural cystidia) is a relatively large cell found on the sporocarp of a basidiomycete (for example, on the surface of a mushroom gill), often between clusters of basidia. Since cystidia have highly varied and distinct shapes that ar ...

that are not strongly coloured.

Molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

analysis published in 1997 established that the bolete mushrooms are all derived from a common ancestor, and established the

Boletales The Boletales are an order of Agaricomycetes containing over 1300 species with a diverse array of fruiting body types. The boletes are the best known members of this group, and until recently, the Boletales were thought to only contain boletes. ...

as an order separate from the Agaricales. The

generic Generic or generics may refer to: In business * Generic term, a common name used for a range or class of similar things not protected by trademark * Generic brand, a brand for a product that does not have an associated brand or trademark, other ...

name is derived from the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

term ''bōlētus'' "mushroom", which was borrowed in turn from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

βωλίτης, "terrestrial fungus". Ultimately, this last word derives from ''bōlos''/βῶλος "lump", "clod", and, metaphorically, "mushroom". The βωλίτης of

Galen Aelius Galenus or Claudius Galenus ( el, Κλαύδιος Γαληνός; September 129 – c. AD 216), often Anglicized as Galen () or Galen of Pergamon, was a Greek physician, surgeon and philosopher in the Roman Empire. Considered to be one of ...

, like the ''boletus'' of Latin writers like

Martial Marcus Valerius Martialis (known in English as Martial ; March, between 38 and 41 AD – between 102 and 104 AD) was a Roman poet from Hispania (modern Spain) best known for his twelve books of ''Epigrams'', published in Rome between AD 86 and ...

Seneca Seneca may refer to: People and language * Seneca (name), a list of people with either the given name or surname * Seneca people, one of the six Iroquois tribes of North America ** Seneca language, the language of the Seneca people Places Extrat ...

and

Petronius Gaius Petronius Arbiter"Gaius Petronius Arbiter"
Amanita caesarea''. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''edulis'' in Latin means "eatable" or "edible".

Common names

Common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

s for ''B. edulis'' vary by region. The standard Italian name, ''porcino'' (pl. ''porcini''), means ''

porcine The pig (''Sus domesticus''), often called swine, hog, or domestic pig when distinguishing from other members of the genus '' Sus'', is an omnivorous, domesticated, even-toed, hoofed mammal. It is variously considered a subspecies of ''Sus s ...

;'' ''fungo porcino'', in Italian, echoes the term ''suilli'', literally "hog mushrooms", a term used by the Ancient Romans and still in use in southern Italian terms for this species. The derivation has been ascribed to the resemblance of young fruit bodies to piglets, or to the fondness pigs have for eating them.Carluccio, pp. 36–38. It is also known as "king bolete". The English ''

penny bun A penny bun or a penny loaf was a small bread bun or loaf which cost one old penny at the time when there were 240 pence to the pound. A penny loaf was a common size loaf of bread in England regulated by the Assize of Bread and Ale act of 1266. ...

'' refers to its rounded brownish shape. The German name ''Steinpilz'' (stone mushroom) refers to the species' firm flesh. In Austria, it is called ''Herrenpilz'', the "noble mushroom", while in Mexico, the Spanish name is ''panza'', meaning "belly". Another Spanish name, ''rodellon'', means "small round boulder", while the

Dutch Dutch commonly refers to: * Something of, from, or related to the Netherlands * Dutch people () * Dutch language () Dutch may also refer to: Places * Dutch, West Virginia, a community in the United States * Pennsylvania Dutch Country People E ...

name ''eekhoorntjesbrood'' means "squirrel's bread". 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 Catalan may refer to: Catalonia From, or related to Catalonia: * Catalan language, a Romance language * Catalans, an ethnic group formed by the people from, or with origins in, Northern or southern Catalonia Places * 13178 Catalan, asteroid #1 ...

''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 ''cep'' "trunk" for its fat stalk, ultimately from the

''cippus'' "stake". ''Ceppatello'', ''ceppatello buono'', ''ceppatello bianco'', ''giallo leonato'', ''ghezzo'', and ''moreccio'' are names from Italian dialects, and ''ciurenys'' or ''surenys'' is another term in Catalan. The French-born King

Charles XIV John sv, Karl Johan Baptist Julius , spouse = , issue = Oscar I of Sweden , house = Bernadotte , father = Henri Bernadotte , mother = Jeanne de Saint-Jean , birth_date = , birth_place = Pau, ...

popularised ''B. edulis'' in Sweden after 1818, 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 Rosersberg Palace ( sv, Rosersbergs slott) is one of the Royal Palaces of Sweden. Situated on the shores of Lake Mälaren, on the outskirts of Stockholm, it was built in the 1630s by the Oxenstierna family and became a royal palace in 1762, when ...

. The Finnish name is ''herkkutatti'', ''herkku'' from ''herkullinen'', which means delicious, and ''tatti'', describing the type of mushroom.

Description

The

of this mushroom is 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, or stem, is in height, and up to thick—rather large in comparison to the cap; it is club-shaped, or bulges out in the middle. It is finely

reticulate Reticulation is a net-like pattern, arrangement, or structure. Reticulation or Reticulated may refer to: * Reticulation (single-access key), a structure of an identification tree, where there are several possible routes to a correct identificatio ...

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

production; they are deep, and whitish in colour when young, but mature to a greenish-yellow. The angular pores, which do not stain when bruised, are small—roughly 2 to 3 pores per millimetre. In youth, the pores are white and appear as if stuffed with cotton (which are actually

mycelia Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates ...

); 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. Fully mature specimens can weigh about ; a huge specimen collected on the

Isle of Skye The Isle of Skye, or simply Skye (; gd, An t-Eilean Sgitheanach or ; sco, Isle o Skye), is the largest and northernmost of the major islands in the Inner Hebrides of Scotland. The island's peninsulas radiate from a mountainous hub dominated ...

, Scotland, in 1995 bore a cap of , with a stipe in height and wide, and weighed . A similarly sized specimen found in Poland in 2013 made international news. ''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. The most similar poisonous mushroom may be the devil's bolete (''

Rubroboletus satanas ''Rubroboletus satanas'', commonly known as Satan's bolete or the Devil's bolete, is a basidiomycete fungus of the bolete family (Boletaceae) and one of its most infamous members. It was known as ''Boletus satanas'' before its transfer to the ...

''), which has a similar shape, but has a red stem and stains blue on bruising. It is often confused with the very bitter and unpalatable ''

Tylopilus felleus ''Tylopilus felleus'', commonly known as the bitter bolete or the bitter tylopilus, is a fungus of the bolete family. Its distribution includes east Asia, Europe and eastern North America, extending south into Mexico and Central America. A m ...

'', 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. It can also resemble the "bolete-like" ''

Gyroporus castaneus ''Gyroporus castaneus'', or commonly the chestnut bolete, is a small, white-pored relation of the ''Boletus'' mushrooms. It has a brown cap, and is usually found with oak trees. It differs from the true boletes in that the spores are a pale stra ...

'', which is generally smaller, and has a browner stem. ''

Boletus huronensis ''Boletus'' is a genus of mushroom-producing fungi, comprising over 100 species. The genus ''Boletus'' was originally broadly defined and described by Carl Linnaeus in 1753, essentially containing all fungi with hymenial pores instead of gil ...

,'' an uncommon mushroom of northeastern North America, is another recognized look-alike known to cause severe

gastrointestinal disorder Gastrointestinal diseases (abbrev. GI diseases or GI illnesses) refer to diseases involving the Human gastrointestinal tract, gastrointestinal tract, namely the oesophagus, stomach, small intestine, large intestine and rectum, and the accessory org ...

s. The

spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

are elliptical to spindle-shaped, with dimensions of 12–17 by 5–7 µm. The

basidia A basidium () is a microscopic sporangium (a spore-producing structure) found on the hymenophore of fruiting bodies of basidiomycete fungi which are also called tertiary mycelium, developed from secondary mycelium. Tertiary mycelium is highly-c ...

, 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 hymenium is the tissue layer on the hymenophore of a fungal fruiting body where the cells develop into basidia or asci, which produce spores. In some species all of the cells of the hymenium develop into basidia or asci, while in others some ...

. The basidia are thin-walled, mostly attached to four spores, and measure 25–30 by 8–10 µm. Another cell type present in the hymenium is the cystidia, larger sterile cells that protrude beyond the basidia into the lumen of the hymenium, and act as air traps, regulating humidity. ''B. edulis'' has pleurocystidia (cystidia located on the face of a pore) that are thin-walled, roughly spindle-shaped to

ventricose Ventricose is an adjective describing the condition of a mushroom, gastropod or plant that it is "swollen, distended, or inflated especially on one side". Mycology In mycology, ventricose is a condition in which the cystidia, lamella or stipe of a ...

, and measure 30–45 by 7–10 µm; the "stuffed" feature of the hymenium is caused by cheilocystidia—cells found on the edges of the pores. The

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one or ...

e of ''B. edulis'' do not have

clamp connection A clamp connection is a hook-like structure formed by growing hyphal cells of certain fungi. It is a characteristic feature of Basidiomycetes fungi. It is created to ensure that each cell, or segment of hypha separated by septa (cross walls), rece ...

Related species

Several similar brownish-coloured species are sometimes considered subspecies or forms of this mushroom. In Europe, in addition to ''B. edulis'' (or ''cèpe de Bordeaux''), the most popular are: *''Cèpe bronzé'' ("dark cep"; ''

Boletus aereus ''Boletus aereus'', the dark cep or bronze bolete, is a highly prized and much sought-after edible mushroom in the family Boletaceae. The bolete is widely consumed in Spain (Basque Country (greater region), Basque Country and Navarre), Fran ...

''), much rarer than ''B. edulis'', is more highly regarded by gourmets, and consequently more expensive. Usually smaller than ''B. edulis'', it is also distinctively darker in colour. It is especially suited to drying. *''Cèpe des pins'' ("pine tree cep"; ''

Boletus pinophilus ''Boletus pinophilus'', commonly known as the pine bolete or pinewood king bolete, is a basidiomycete fungus of the genus ''Boletus'' found throughout Europe and western Asia. Described by Italian naturalist Carlo Vittadini in 1835, ''B. ...

'' or ''Boletus pinicola'') grows among pine trees. Rarer than ''B. edulis'', it is less appreciated by gourmets than the two other kinds of porcini, but remains a mushroom rated above most others. *''Cèpe d'été'' ("summer cep"; ''

Boletus reticulatus ''Boletus reticulatus'' (alternately known as ''Boletus aestivalis'' (Paulet) Fr.), and commonly referred to as the summer cep is a basidiomycete fungus of the genus ''Boletus''. It occurs in deciduous forests of Europe where it forms a symbio ...

''), also less common and found earlier.

Molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

analyses have proven these three are all distinctive and separate species; other taxa formerly believed to be unique species or subspecies, such as ''B. betulicola'', ''B. chippewaensis'', ''B. persoonii'', ''B. quercicola'' and ''B. venturii'', are now known to be part of a ''B. edulis''

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

with a wide morphological, ecological and geographic range, and that the genetic variability in this complex is low. Similar molecular technology has been developed to rapidly and accurately identify ''B. edulis'' and other commercially important fungi. Three divergent lineages found in Yunnan province in China that are commonly marketed and sold as ''B. edulis'' (and are actually more closely related to ''B. aereus'') were described in 2013 as '' B. bainiugan'', '' B. meiweiniuganjun'' and '' B. shiyong''. 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. Boletus rex-veris 42967

Western North America has several species closely related to ''B. edulis''. The white king bolete (''

Boletus barrowsii ''Boletus barrowsii'', also known in English as the white king bolete after its pale colored cap, is an edible and highly regarded fungus in the genus ''Boletus'' that inhabits western North America. Found under ponderosa pine and live oak in a ...

''), found in parts of

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe , LargestCity = Albuquerque , LargestMetro = Tiguex , OfficialLang = None , Languages = English, Spanish ( New Mexican), Navajo, Ker ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

, and California (and possibly elsewhere), is named after its discoverer Chuck Barrows. It is lighter in colour than ''B. edulis'', having a cream-coloured cap with pink tones; often mycorrhizal with

Ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...

, it tends to grow in areas where there is less rainfall. Some find its flavour as good as if not better than ''B. edulis''. The California king bolete (''Boletus edulis var. grandedulis'') can reach massive proportions, and is distinguished from ''B. 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

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an a ...

, to dark-brown, red-brown or yellow brown in those specimens receiving more light. The queen bolete (''

Boletus regineus ''Boletus regineus'', commonly known as the queen bolete, is an edible and highly regarded fungus of the genus ''Boletus'' that inhabits southwestern North America. It was considered a variant of the similarly edible '' B. edulis'' for man ...

''), formerly considered a variety of ''B. aereus'', is also a choice edible. It is generally smaller than ''B. edulis'', and unlike that species, is typically found in

mixed forest Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions. These fo ...

s. The spring king bolete (''

Boletus rex-veris ''Boletus rex-veris'', commonly known as the spring king bolete, is a basidiomycete fungus of the genus ''Boletus'' found in western North America. The large, edible fruiting bodies known as mushrooms appear under pine trees, generally in May t ...

''), formerly considered a variety of ''B. edulis'' or ''B. pinophilus'', is found throughout western North America. In contrast to ''B. edulis'', ''B. rex-veris'' tends to fruit in clusters, and, as its common name suggests, appears in the spring. '' B. fibrillosus'' is edible but considered inferior in taste.

Habitat and distribution

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 A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

'' spp.), spruce (''

Picea A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

'' spp.), hemlock (''

Tsuga ''Tsuga'' (, from Japanese (), the name of ''Tsuga sieboldii'') is a genus of conifers in the subfamily Abietoideae of Pinaceae, the pine family. The common name hemlock is derived from a perceived similarity in the smell of its crushed folia ...

'' spp.) and fir (''

Abies Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family Pinaceae. They are found on mountains throughout much of North and Central America, Europe, Asia, and North Africa. The genus is most closely related to ...

'' spp.) trees, although other hosts include

chestnut The chestnuts are the deciduous trees and shrubs in the genus ''Castanea'', in the beech family Fagaceae. They are native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce. The unrelat ...

, chinquapin,

beech Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engle ...

, ''

Keteleeria ''Keteleeria'' is a genus of three species of coniferous trees in the family Pinaceae first described as a genus in 1866. The genus name ''Keteleeria'' honours J.B. Keteleer (1813–1903), a French nurseryman. The group is related to the genera ...

'' spp., ''

Lithocarpus ''Lithocarpus'' is a genus in the beech family, Fagaceae. Trees in this genus are commonly known as the stone oaks and differ from ''Quercus'' primarily because they produce insect-pollinated flowers on erect spikes and the female flowers have ...

'' spp., and

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

. In California, porcini have been collected in a variety of forests, such as coastal forests, dry interior oak forests and

savanna A savanna or savannah is a mixed woodland-grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...

s and interior high-elevation

montane Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial f ...

s, to an altitude of . In northwestern Spain, they are common in

scrubland Shrubland, scrubland, scrub, brush, or bush is a plant community characterized by vegetation dominance (ecology), dominated by shrubs, often also including grasses, Herbaceous plant, herbs, and geophytes. Shrubland may either occur naturally or ...

s dominated by the

rock rose Rock most often refers to: * Rock (geology), a naturally occurring solid aggregate of minerals or mineraloids * Rock music, a genre of popular music Rock or Rocks may also refer to: Places United Kingdom * Rock, Caerphilly, a location in Wales ...

species ''

Cistus ladanifer ''Cistus ladanifer'' is a species of flowering plant in the family Cistaceae. It is native to the western Mediterranean region. Common names include gum rockrose, labdanum, common gum cistus, and brown-eyed rockrose. Description It is a shru ...

'' and ''Halimium lasianthum''. In 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. ''Boletus edulis'' has a

cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the world in appropriate habitats. Such a taxon, usually a species, is said to exhibit cosmopolitanism or cosmopolitism. The ext ...

, concentrated in cool-

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

subtropical The subtropical zones or subtropics are geographical zone, geographical and Köppen climate classification, climate zones to the Northern Hemisphere, north and Southern Hemisphere, south of the tropics. Geographically part of the Geographical z ...

regions. 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. It is well known from the

Borgotaro Borgo Val di Taro, usually referred to as Borgotaro, ( Parmigiano: ; locally ) is a town and ''comune'' in Emilia, Italy, in the Province of Parma, from the city of Parma. Borgo Val di Taro is an important centre for cattle husbandry in Emilia a ...

area of

Parma Parma (; egl, Pärma, ) is a city in the northern Italian region of Emilia-Romagna known for its architecture, Giuseppe Verdi, music, art, prosciutto (ham), Parmigiano-Reggiano, cheese and surrounding countryside. With a population of 198,292 ...

, Italy, and has PGI status there. The European distribution extends north to Scandinavia and south to southern Italy and Morocco. In China, the mushroom can be found from the northeastern

Heilongjiang Heilongjiang () formerly romanized as Heilungkiang, is a province in northeast China. The standard one-character abbreviation for the province is (). It was formerly romanized as "Heilungkiang". It is the northernmost and easternmost province ...

to the

Yunnan–Guizhou Plateau The Yunnan–Guizhou Plateau or Yungui Plateau () is a highland region located in southwest China. The region is primarily spread over the provinces of Yunnan and Guizhou. In the southwest, the Yungui is a true plateau with relatively flatter ...

and

Tibet Tibet (; ''Böd''; ) is a region in East Asia, covering much of the Tibetan Plateau and spanning about . It is the traditional homeland of the Tibetan people. Also resident on the plateau are some other ethnic groups such as Monpa people, ...

. It has been recorded growing under ''Pinus'' and ''Tsuga'' in

Sagarmatha National Park Sagarmāthā National Park is a national park in the Himalayas of eastern Nepal that is dominated by Mount Everest. It encompasses an area of in the Solukhumbu District and ranges in elevation from at the summit of Mount Everest. In the north, i ...

in Nepal, as well as in the Indian forests of

Arunachal Pradesh Arunachal Pradesh (, ) is a state in Northeastern India. It was formed from the erstwhile North-East Frontier Agency (NEFA) region, and became a state on 20 February 1987. It borders the states of Assam and Nagaland to the south. It shares int ...

. In West Asia, the species has been reported from the northwest forests of Iran.

Cultivation

Some steps have been made towards cultivating ''Boletus edulis'', including mycorrhization of rockrose shrubs enhanced by helper bacteria.

Non-native introductions

''Boletus edulis'' grows in some areas where it is not believed to be

indigenous Indigenous may refer to: *Indigenous peoples *Indigenous (ecology), presence in a region as the result of only natural processes, with no human intervention *Indigenous (band), an American blues-rock band *Indigenous (horse), a Hong Kong racehorse ...

. It is often found underneath oak and

silver birch ''Betula pendula'', commonly known as silver birch, warty birch, European white birch, or East Asian white birch, is a species of tree in the family Betulaceae, native to Europe and parts of Asia, though in southern Europe, it is only found ...

in Hagley Park in central

Christchurch Christchurch ( ; mi, Ōtautahi) is the largest city in the South Island of New Zealand and the seat of the Canterbury Region. Christchurch lies on the South Island's east coast, just north of Banks Peninsula on Pegasus Bay. The Avon River / ...

, New Zealand, where it is likely to have been introduced, 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. Similarly, it has been collected in Adelaide Hills region of Australia in association with three species of introduced trees. It has been growing plentifully in association with pine forests in the southern

KwaZulu-Natal Midlands The KwaZulu-Natal midlands is an inland area of KwaZulu-Natal, South Africa that starts from Pietermaritzburg and ends before the Drakensberg mountain range. Area There are several small towns located in the midlands, including: Pietermaritzbu ...

in South Africa for more than 50 years and is believed to have been introduced with the import of pine trees. It also grows in pine plantations in neighboring Zimbabwe.

Ecology

Fruit body production

Italian folklore holds that porcini sprout up at the time of the new moon; 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. 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". A 2004

field study Field research, field studies, or fieldwork is the collection of raw data outside a laboratory, library, or workplace setting. The approaches and methods used in field research vary across disciplines. For example, biologists who conduct fi ...

indicated that fruit body production is enhanced by an open and sunny wood habitat, corroborating an earlier observation made in a Zimbabwean study; removal of the litter layer on the

forest floor The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages ...

appeared to have a negative effect on fruit body production, but previous studies reported contradictory results. A Lithuanian study conducted in 2001 concluded that the maximal daily growth rate of the cap (about 21 mm or 0.8 in) occurred when the

relative air humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

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 Frost is a thin layer of ice on a solid surface, which forms from water vapor in an above-freezing atmosphere coming in contact with a solid surface whose temperature is below freezing, and resulting in a phase change from water vapor (a gas) ...

. Plots facing north tend to produce more mushrooms compared to equivalent plots facing south.

Mycorrhizal associations

''Boletus edulis'' is

mycorrhiza A mycorrhiza (from Greek μύκης ', "fungus", and ῥίζα ', "root"; pl. mycorrhizae, mycorrhiza or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant ...

l—it is in a mutualistic relationship with the roots of plants (hosts), in which the fungus exchanges

nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...

and other nutrients extracted from the environment for

fixed carbon Biological carbon fixation or сarbon assimilation is the process by which inorganic carbon (particularly in the form of carbon dioxide) is converted to organic compounds by living organisms. The compounds are then used to store energy and as ...

from the host. Other benefits for the plant are evident: in the case of the Chinese chestnut, the formation of mycorrhizae with ''B. edulis'' increases the ability of plant seedlings to resist

water stress Water scarcity (closely related to water stress or water crisis) is the lack of fresh water resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water scarcity is where ...

, and increases leaf succulence, leaf area, and water-holding ability. 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 Hartig net is a network of inward-growing Hypha, hyphae, that extends into the root, penetrating between the epidermis and cortex of ectomycorrhizal plants. This network is a site of nutrient exchange between the fungus and the host plant. The Har ...

.Smith, Sally; Read, David. Mycorrhizal Symbiosis. Academic press, 1996 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. Compatible hosts may belong to multiple families of

vascular plant Vascular plants (), also called tracheophytes () or collectively Tracheophyta (), form a large group of land plants ( accepted known species) that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They al ...

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. Examples of mycorrhizal associates include Chinese red pine, Mexican weeping pine,

Scots pine ''Pinus sylvestris'', the Scots pine (UK), Scotch pine (US) or Baltic pine, is a species of tree in the pine family Pinaceae that is native to Eurasia. It can readily be identified by its combination of fairly short, blue-green leaves and orang ...

Norway spruce ''Picea abies'', the Norway spruce or European spruce, is a species of spruce native to Northern, Central and Eastern Europe. It has branchlets that typically hang downwards, and the largest cones of any spruce, 9–17 cm long. It is very close ...

Coast Douglas-fir ''Pseudotsuga menziesii'' var. ''menziesii'', commonly known as Coast Douglas-fir, Pacific Douglas-fir, Oregon pine, or Douglas spruce, is an evergreen conifer native to western North America from west-central British Columbia, Canada southward t ...

mountain pine ''Pinus mugo'', known as bog pine, creeping pine, dwarf mountain pine, mugo pine, mountain pine, scrub mountain pine, or Swiss mountain pine, is a species of conifer, native to high elevation habitats from southwestern to Central Europe and S ...

, and

Virginia pine ''Pinus virginiana'', the Virginia pine, scrub pine, Jersey pine, Possum pine, is a medium-sized tree, often found on poorer soils from Long Island in southern New York south through the Appalachian Mountains to western Tennessee and Alabama. The ...

. The fungus has also been shown to associate with

gum rockrose ''Cistus ladanifer'' is a species of flowering plant in the family Cistaceae. It is native to the western Mediterranean region. Common names include gum rockrose, labdanum, common gum cistus, and brown-eyed rockrose. Description It is a shrub ...

, a

pioneer Pioneer commonly refers to a settler who migrates to previously uninhabited or sparsely inhabited land. In the United States pioneer commonly refers to an American pioneer, a person in American history who migrated west to join in settling and de ...

early stage shrub that is adapted for growth in degraded areas, such as burned forests. These and other rockrose species are ecologically important as fungal reservoirs, maintaining an inoculum of mycorrhizal fungi for trees that appear later in the forest regrowth cycle. The mushroom has been noted to often co-occur with ''

Amanita muscaria ''Amanita muscaria'', commonly known as the fly agaric or fly amanita, is a basidiomycete of the genus ''Amanita''. It is also a muscimol mushroom. Native throughout the temperate and boreal regions of the Northern Hemisphere, ''Amanita muscar ...

'' or '' A. 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. An association has also been reported between ''B. edulis'' and ''

Amanita excelsa ''Amanita excelsa'', also known as the European false blushing amanita, is a species of agaric fungus in the family Amanitaceae. It is found in Asia, Europe, and North America, where it grows in deciduous forests. Amanita excelsa var. spissa is ...

'' on ''

Pinus radiata ''Pinus radiata'' ( syn. ''Pinus insignis''), the Monterey pine, insignis pine or radiata pine, is a species of pine native to the Central Coast of California and Mexico (Guadalupe Island and Cedros island). It is an evergreen conifer in the fa ...

'' ectomycorrhizae in New Zealand, suggesting that other fungi may influence the life cycle of porcini. 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.

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 Phytochelatins are oligomers of glutathione, produced by the enzyme phytochelatin synthase. They are found in plants, fungi, nematodes and all groups of algae including cyanobacteria. Phytochelatins act as chelators, and are important for heav ...

—an

oligopeptide An oligopeptide, often just called peptide ('' oligo-'', "a few"), consists of two to twenty amino acids and can include dipeptides, tripeptides, tetrapeptides, and pentapeptides. Some of the major classes of naturally occurring oligopeptides incl ...

whose production is induced after exposure to metal. Phytochelatins are

chelating agents Chelation is a type of bonding of ions and molecules to metal ions. It involves the formation or presence of two or more separate coordinate bonds between a polydentate (multiple bonded) ligand and a single central metal atom. These ligands are ...

, capable of forming 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.

Pests and predators

The fruit bodies of ''B. edulis'' can be infected by the parasitic mould-like fungus ''

Hypomyces chrysospermus ''Hypomyces chrysospermus'', the bolete eater, is a parasitic ascomycete fungus that grows on bolete mushrooms, turning the afflicted host a whitish, golden yellow, or tan color. It is found in Eurasia and North America, as well as southwest We ...

'', known as the bolete eater, which manifests itself as a white, yellow, or reddish-brown cottony layer over the surface of the mushroom. Some reported cases of

stomach ache Abdominal pain, also known as a stomach ache, is a symptom associated with both non-serious and serious medical issues. Common causes of pain in the abdomen include gastroenteritis and irritable bowel syndrome. About 15% of people have a m ...

following consumption of dried porcini have been attributed to the presence of this mould on the fruit bodies. The mushroom is also used as a food source by several species of mushroom flies, as well as other insects and their

larvae A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

. 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". ''Boletus edulis'' is a food source for animals such as the

banana slug Banana slugs are North American terrestrial slugs comprising the genus ''Ariolimax''. MolluscaBase eds. (2021). MolluscaBase. Ariolimax Mörch, 1859. Accessed through: World Register of Marine Species at: http://www.marinespecies.org/aphia.php?p= ...

''(Ariolimax columbianus)'', the

long-haired grass mouse ''Abrothrix longipilis'', also known as the long-haired grass mouse or long-haired akodont,Musser and Carleton, 2005, p. 1089 is a species of rodent in the family Cricetidae. It is found in central and southern Argentina and Chile. The south ...

, the

red squirrel The red squirrel (''Sciurus vulgaris'') is a species of tree squirrel in the genus ''Sciurus'' common throughout Europe and Asia. The red squirrel is an arboreal, primarily herbivorous rodent. In Great Britain, Ireland, and in Italy numbers ...

, and, as noted in one isolated report, the

fox sparrow The fox sparrow (''Passerella iliaca'') is a large New World sparrow. It is the only member of the genus ''Passerella'', although some authors split the species into four (see below). Taxonomy More specific information regarding plumage is avai ...

Culinary uses

''Boletus edulis'', as the species

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

''edulis'' (Latin: 'edible') directly implies, is an

. Italian chef and restaurateur

Antonio Carluccio Antonio Carluccio, OBE OMRI (; 19 April 1937 – 8 November 2017) was an Italian chef, restaurateur and food expert, based in London. He was called "the godfather of Italian gastronomy", with a career of more than 50 years. He is perhaps best re ...

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. Considered a choice edible, particularly in France, Germany, Poland and Italy, it was widely written about by the Roman writers

Pliny the Elder Gaius Plinius Secundus (AD 23/2479), called Pliny the Elder (), was a Roman author, naturalist and natural philosopher, and naval and army commander of the early Roman Empire, and a friend of the emperor Vespasian. He wrote the encyclopedic '' ...

and Martial, although ranked below the esteemed '' Amanita caesarea''. When served ''suilli'' instead of ''boleti'', the disgruntled Martial wrote: The flavour has been described as nutty and slightly meaty, with a smooth, creamy texture, and a distinctive aroma reminiscent of

sourdough Sourdough or sourdough bread is a bread made by the fermentation of dough using wild lactobacillaceae and yeast. Lactic acid from fermentation imparts a sour taste and improves keeping qualities. History In the ''Encyclopedia of Food Microbio ...

. Young, small porcini are most appreciated by gourmets, as the large ones often harbour

maggot A maggot is the larva of a fly (order Diptera); it is applied in particular to the larvae of Brachycera flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and crane flies. ...

s (insect larvae), and become slimy, soft and less tasty with age. 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. The fruit bodies are highly

perishable Decomposition or rot is the process by which dead organic substances are broken down into simpler organic or inorganic matter such as carbon dioxide, water, simple sugars and mineral salts. The process is a part of the nutrient cycle and is ...

, due largely to the high water content (around 90%), the high level of

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

activity, and the presence of a flora of microorganisms. Caution should be exercised when collecting specimens from potentially polluted or

contaminated Contamination is the presence of a constituent, impurity, or some other undesirable element that spoils, corrupts, infects, makes unfit, or makes inferior a material, physical body, natural environment, workplace, etc. Types of contamination ...

sites, as several studies have shown that the fruit bodies can

bioaccumulate Bioaccumulation is the gradual accumulation of substances, such as pesticides or other chemicals, in an organism. Bioaccumulation occurs when an organism absorbs a substance at a rate faster than that at which the substance is lost or eliminated ...

toxic heavy metals like

mercury Mercury commonly refers to: * Mercury (planet), the nearest planet to the Sun * Mercury (element), a metallic chemical element with the symbol Hg * Mercury (mythology), a Roman god Mercury or The Mercury may also refer to: Companies * Merc ...

cadmium Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...

caesium Caesium (IUPAC spelling) (or cesium in American English) is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only five elemental metals that a ...

and

polonium Polonium is a chemical element with the symbol Po and atomic number 84. Polonium is a chalcogen. A rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character ...

. Bioaccumulated metals or radioactive fission decay products are like chemical signatures:

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...

and radiochemical analysis can be used to identify the origin of imported specimens, and for long-term radioecological monitoring of polluted areas. Porcini mushroom soup in breadbowl poland 2010

Porcini mushroom soup in breadbowl poland 2010

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. 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''. Porcini

is a traditional Italian autumn dish. Porcini are a feature of many cuisines, including Provençal, and

Viennese Viennese may refer to: * Vienna, the capital of Austria * Viennese people, List of people from Vienna * Viennese German, the German dialect spoken in Vienna * Music of Vienna, musical styles in the city * Viennese Waltz, genre of ballroom dance * V ...

. They are used in soups and consumed blanched in salads in

Thailand Thailand ( ), historically known as Siam () and officially the Kingdom of Thailand, is a country in Southeast Asia, located at the centre of the Indochinese Peninsula, spanning , with a population of almost 70 million. The country is bo ...

. Porcini can also be frozen—either raw or first cooked in butter. The colour, aroma, and taste of frozen porcini deteriorate noticeably if frozen longer than four months.

Blanching Blanch or blanching may refer to: People * Andrea Blanch (born 1935), portrait, commercial, and fine art photographer * Arnold Blanch (1896–1968), born and raised in Mantorville, Minnesota * Stuart Blanch, Baron Blanch (1918–1994), Anglican bi ...

or soaking and blanching as a processing step before freezing can extend the freezer life up to 12 months. They are also one of the few mushroom species pickled and sold commercially.

Dried

''Boletus edulis'' is well suited to drying—its flavour intensifies, it is easily reconstituted, and its resulting texture is pleasant. 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 The soybean, soy bean, or soya bean (''Glycine max'') is a species of legume native to East Asia, widely grown for its edible bean, which has numerous uses. Traditional unfermented food uses of soybeans include soy milk, from which tofu an ...

s. Some of this content is indigestible, though digestibility is improved with cooking. 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 Bamboo steamers, called ''zhēnglóng'' () in Chinese,it originated in Han Dynasty． The most famous kind of bamboo steamers are used in Chinese cuisine and date back to 5,000 years in Southern China. They are produced by removing the skin from ...

on top of a boiler or hot water tank.Carluccio, p. 97. Another method is drying in an oven at for two to three hours, then increasing the temperature to until crisp or brittle. Once dry, they are kept in an airtight jar. Importantly for commercial production, porcini retain their flavour after industrial preparation in a

pressure cooker Pressure cooking is the process of cooking food under high pressure steam and water or a water-based cooking liquid, in a sealed vessel known as a ''pressure cooker''. High pressure limits boiling, and creates higher cooking temperatures which c ...

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). The drying process is known to induce the formation of various 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.

Commercial harvest

A 1998 estimate suggests the total annual worldwide consumption of ''Boletus edulis'' and closely related species (''B. aereus'', ''B. pinophilus'', and ''B. reticulatus'') to be between 20,000 and 100,000 tons. Approximately 2,700 tonnes (3,000 tons) were sold in France, Italy and Germany in 1988, according to official figures. The true amount consumed far exceeds this, as it does not account for informal sales or consumption by collectors. 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 Castile and León ( es, Castilla y León ; ast-leo, Castiella y Llión ; gl, Castela e León ) is an autonomous community in northwestern Spain. It was created in 1983, eight years after the end of the Francoist regime, by the merging of the ...

in Spain produces 7,700 tonnes (8,500 tons) annually. In autumn, the price of porcini in the Northern Hemisphere typically ranges between $20 and $80 per kilogram, although in New York in 1997 the scarcity of fruit bodies elevated the wholesale price to more than $200 per kilogram. In the vicinity of

in the

Province of Parma The Province of Parma ( it, Provincia di Parma) is a province in the Emilia–Romagna region of Italy. Its largest town and capital is the city of Parma. It is made up of 47 ''comuni''. It has an area of and a total population of around 450,000 ...

of northern Italy, the four species ''Boletus edulis'', ''B. aereus'', ''B. aestivalis'' and ''B. 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 globalization 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 imported into Italy from various locations, especially China and eastern European countries; these are then often re-exported under the "Italian porcini" label. 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 ''Tylopilus'' is a genus of over 100 species of mycorrhizal bolete fungi separated from ''Boletus''. Its best known member is the bitter bolete (''Tylopilus felleus''), the only species found in Europe. More species are found in North America, s ...

'', 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. After the

fall of the Iron Curtain The Revolutions of 1989, also known as the Fall of Communism, was a revolutionary wave that resulted in the end of most communist states in the world. Sometimes this revolutionary wave is also called the Fall of Nations or the Autumn of Natio ...

and the economic and political barriers that followed, 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. Exported porcini and other wild fungi are also destined for France, Germany and other western European markets, where demand for them exists, but collection on a commercial scale does not. Picking ''B. edulis'' has become an annual seasonal income earner and pastime in countries like

Bulgaria Bulgaria (; bg, България, Bǎlgariya), officially the Republic of Bulgaria,, ) is a country in Southeast Europe. It is situated on the eastern flank of the Balkans, and is bordered by Romania to the north, Serbia and North Macedon ...

, especially for many

Roma Roma or ROMA may refer to: Places Australia * Roma, Queensland, a town ** Roma Airport ** Roma Courthouse ** Electoral district of Roma, defunct ** Town of Roma, defunct town, now part of the Maranoa Regional Council *Roma Street, Brisbane, a ...

communities and the

unemployed Unemployment, according to the OECD (Organisation for Economic Co-operation and Development), is people above a specified age (usually 15) not being in paid employment or self-employment but currently available for work during the referen ...

. A lack of control has led to heavy exploitation of the mushroom resource. Like many other strictly mycorrhizal fungi, ''B. edulis'' has eluded cultivation attempts for years. The results of some studies suggest that unknown components of the soil microflora might be required for ''B. edulis'' to establish a mycorrhizal relationship with the host plant. Successful attempts at cultivating ''B. edulis'' have been made by Spanish scientists by mycorrhization of ''Cistus'' species, with ''Pseudomonas fluorescens'' bacteria helping the mycorrhiza.

Nutrition

''Boletus edulis'' mushrooms are 9%

s, 3% fat, and 7%

(table). Fresh mushrooms consist of over 80% moisture, although reported values tend to differ somewhat as moisture content can be affected by environmental temperature and

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

during growth and storage. The carbohydrate component contains the

monosaccharide Monosaccharides (from Greek ''monos'': single, '' sacchar'': sugar), also called simple sugars, are the simplest forms of sugar and the most basic units (monomers) from which all carbohydrates are built. They are usually colorless, water-solub ...

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

mannitol Mannitol is a type of sugar alcohol used as a sweetener and medication. It is used as a low calorie sweetener as it is poorly absorbed by the intestines. As a medication, it is used to decrease pressure in the eyes, as in glaucoma, and to lower ...

and α,α-

trehalose Trehalose (from Turkish '' tıgala'' – a sugar derived from insect cocoons + -ose) is a sugar consisting of two molecules of glucose. It is also known as mycose or tremalose. Some bacteria, fungi, plants and invertebrate animals synthesize it ...

, the

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...

glycogen Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one o ...

, and the water-insoluble structural polysaccharide

chitin Chitin ( C8 H13 O5 N)n ( ) is a long-chain polymer of ''N''-acetylglucosamine, an amide derivative of glucose. Chitin is probably the second most abundant polysaccharide in nature (behind only cellulose); an estimated 1 billion tons of chit ...

, which accounts for up to 80–90% of dry matter in mushroom

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...

s. Chitin,

hemicellulose A hemicellulose (also known as polyose) is one of a number of heteropolymer, heteropolymers (matrix polysaccharides), such as arabinoxylans, present along with cellulose in almost all embryophyte, terrestrial plant cell walls.Scheller HV, Ulvskov H ...

, and

pectin Pectin ( grc, πηκτικός ': "congealed" and "curdled") is a heteropolysaccharide, a structural acid contained in the primary lamella, in the middle lamella, and in the cell walls of terrestrial plants. The principal, chemical component of ...

-like carbohydrates—all indigestible by humans—contribute to high proportion of insoluble fibre in ''B. edulis''. The total

lipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include ...

, or crude fat, content makes up 3% of the dry matter of the mushroom. The proportion of

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, fr ...

s (expressed as a % of total fatty acids) are:

palmitic acid Palmitic acid (hexadecanoic acid in IUPAC nomenclature) is a fatty acid with a 16-carbon chain. It is the most common saturated fatty acid found in animals, plants and microorganisms.Gunstone, F. D., John L. Harwood, and Albert J. Dijkstra. The Li ...

, 10%;

stearic acid Stearic acid ( , ) is a saturated fatty acid with an 18-carbon chain. The IUPAC name is octadecanoic acid. It is a waxy solid and its chemical formula is C17H35CO2H. Its name comes from the Greek word στέαρ "''stéar''", which means tallow. ...

, 3%;

oleic acid Oleic acid is a fatty acid that occurs naturally in various animal and vegetable fats and oils. It is an odorless, colorless oil, although commercial samples may be yellowish. In chemical terms, oleic acid is classified as a monounsaturated omega ...

, 36%; and

linoleic acid Linoleic acid (LA) is an organic compound with the formula COOH(CH2)7CH=CHCH2CH=CH(CH2)4CH3. Both alkene groups are cis-trans isomerism, ''cis''. It is a fatty acid sometimes denoted 18:2 (n-6) or 18:2 ''cis''-9,12. A linoleate is a salt (chem ...

, 42%. A comparative study of the

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

composition of eleven Portuguese wild edible mushroom species showed ''Boletus edulis'' to have the highest total amino acid content. ''B. edulis'' mushrooms are rich in the

dietary minerals In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, ...

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable iso ...

, iron,

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...

, and

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ta ...

, with amounts varying according to the mushroom component and to soil composition in the geographic region of China where they were sampled. They also have high content of

B vitamins B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. Though these vitamins share similar names (B1, B2, B3, etc.), they are chemically distinct compounds that often coexist ...

and

tocopherol Tocopherols (; TCP) are a class of organic chemical compounds (more precisely, various methylated phenols), many of which have vitamin E activity. Because the vitamin activity was first identified in 1936 from a dietary fertility factor in rats, i ...

s. ''B. edulis'' contains appreciable amounts of

selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...

, a

trace mineral In the context of nutrition, a mineral is a chemical element required as an essential nutrient by organisms to perform functions necessary for life. However, the four major structural elements in the human body by weight (oxygen, hydrogen, carbon, ...

, although the

bioavailability In pharmacology, bioavailability is a subcategory of absorption and is the fraction (%) of an administered drug that reaches the systemic circulation. By definition, when a medication is administered intravenously, its bioavailability is 100%. H ...

of mushroom-derived selenium is low.

Phytochemicals and research

''Boletus edulis'' fruit bodies contain diverse

phytochemical Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. The name comes . Some phytochemicals have been used as poisons ...

s, including 500 mg of

ergosterol Ergosterol (ergosta-5,7,22-trien-3β-ol) is a sterol found in cell membranes of fungi and protozoa, serving many of the same functions that cholesterol serves in animal cells. Because many fungi and protozoa cannot survive without ergosterol, the ...

per 100 g of dried mushroom, and

ergothioneine Ergothioneine is a naturally occurring amino acid and is a thiourea derivative of histidine, containing a sulfur atom on the imidazole ring. This compound occurs in relatively few organisms, notably actinomycetota, cyanobacteria, and certain fung ...

. The fruit bodies contain numerous

polyphenol Polyphenols () are a large family of naturally occurring organic compounds characterized by multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of ...

s, especially a high content of

rosmarinic acid Rosmarinic acid, named after rosemary (''Salvia rosmarinus'' Linn.), is a polyphenol constituent of many culinary herbs, including rosemary (''Salvia rosmarinus'' L.), perilla (''Perilla frutescens'' L.), Salvia officinalis, sage (''Salvia offic ...

, and

organic acid An organic acid is an organic compound with acidic properties. The most common organic acids are the carboxylic acids, whose acidity is associated with their carboxyl group –COOH. Sulfonic acids, containing the group –SO2OH, are rel ...

s (such as oxalic, citric, malic, succinic and

fumaric acid Fumaric acid is an organic compound with the formula HO2CCH=CHCO2H. A white solid, fumaric acid occurs widely in nature. It has a fruit-like taste and has been used as a food additive. Its E number is E297. The salts and esters are known as fu ...

s), and

alkaloid Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

Aroma

Aroma An odor (American English) or odour (Commonwealth English; see spelling differences) is caused by one or more volatilized chemical compounds that are generally found in low concentrations that humans and animals can perceive via their sense ...

compounds giving ''B. edulis'' mushrooms their characteristic fragrance include some 100 components, such as

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s and

s. In a study of aroma compounds, 1-octen-3-one was the most prevalent chemical detected in raw mushrooms, with

pyrazine Pyrazine is a heterocyclic aromatic organic compound with the chemical formula C4H4N2. It is a symmetrical molecule with point group D2h. Pyrazine is less basic than pyridine, pyridazine and pyrimidine. It is a ''"deliquescent crystal or wax-lik ...

s having increased aroma effect and elevated content after drying.

References

Footnotes Citations

Cited texts

* * * {{Featured article edulis Fungi described in 1782 Fungi of Africa Fungi of Asia Fungi of Europe Fungi of New Zealand Fungi of North America Edible fungi Italian products with protected designation of origin Fungi of Western Asia Taxa named by Jean Baptiste François Pierre Bulliard

Taxonomy

Common names

Description

Related species

Habitat and distribution

Cultivation

Non-native introductions

Ecology

Fruit body production

Mycorrhizal associations

Heavy-metal contamination

Pests and predators

Culinary uses

Dried

Commercial harvest

Nutrition

Phytochemicals and research

Aroma

See also

References

Cited texts