| Boletus pinophilus | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Boletales |
| Family: | Boletaceae |
| Genus: | Boletus |
| Species: | B. pinophilus |
| Binomial name | |
| Boletus pinophilus | |
| Synonyms | |
| Boletus pinophilus | |
|---|---|
| Mycological characteristics | |
 | Pores onhymenium |
 | Cap is convex |
 | Hymenium is adnexed |
 | Stipe is bare |
 | Spore print is olive-brown |
 | Ecology ismycorrhizal |
 | Edibility ischoice |
Boletus pinophilus, commonly known as thepine bolete orpinewood king bolete, is abasidiomycete fungus of the genusBoletus. Described by Italian naturalistCarlo Vittadini in 1835,B. pinophilus was for many years considered asubspecies orform of the porcini mushroomB. edulis before genetic studies confirmed its distinct status. In 2008,B. pinophilus in western North America were reclassified as a new species,B. rex-veris.
The fungus producesspore-bearingfruit bodies (i.e.mushrooms) above ground under pine trees in summer and autumn. It has a red-brown to maroon-coloured cap and a large and bulbousstipe, covered with coarse orange-redreticulation. As with otherboletes, the size of the fruiting body is variable.
The fungus is found throughout Europe and western Asia. It grows predominantly inconiferous forests onsandy soil, formingectomycorrhizal associations insymbiosis with living trees by enveloping the tree's underground roots with sheaths of fungal tissue.Host trees include various species ofpine, theEuropean silver fir andEuropean spruce, as well asdeciduous trees such aschestnut trees,oak andbeech.B. pinophilus isedible, and may be preserved and cooked.
Italian naturalistCarlo Vittadini was the first to recognise the pine bolete as a distincttaxon, describing it asB. edulis var.pinicola in 1835.[6] It was raised to species status (asB. pinicola) byAntonio Venturi in 1863.Pier Andrea Saccardo treated it as a variety ofBoletus aestivalis in 1910.[7] It gained its current name in 1973, described by Czech mycologistsAlbert Pilát andAurel Dermek. A newbinomial name had to be coined asB. pinicola asauthored by Venturi wasinvalid due that name having been previously applied to fungus now known asFomitopsis pinicola.[8] Thespecific epithet is a mix ofLatinpinus "pine",[9] andAncient Greekphilus "loving".[10]B. pinophilus is classified inBoletussectionBoletus; genetic analysis of European members in this group confirmed it is close to but genetically distinct fromB. edulis and proposed maintaining its status as a separate species.[11]
In 2008, ataxonomic revision ofwestern North American populations of this species was published, formally establishing them as a distinct species,B. rex-veris.[12] Populations from eastern North America under pine have been reclassified as a new speciesB. pseudopinophilus. Conversely,B. vinosulus—described from the Czech Republic in 1992—has been sincesynonymised to this species.[5]
Phylogenetic analysis has shownB. pinophilus as a member of aclade, or closely related group, with the North American speciesB. subcaerulescens,B. subalpinus,B. regineus,B. fibrillosus, andB. rex-veris.[13] Despite the diverse appearances, these taxa are close genetically, leading Feng and colleagues to speculate on combining the first four taxa above as a single species.[14] These four diverged from the lineage that gave rise toB. fibrillosus andB. rex-veris around 5 million years ago; the common ancestor of all these diverged from the ancestor ofB. edulis around 10 million years ago.[14]
TheBritish Mycological Society approved the name "pine bolete" forB. pinophilus.[15] Other common names include red king bolete,[5] the pinewood king bolete,[16] andcèpe des pins ("pine tree cep").[17]
The fruiting body has a convex-shapedcap, at first small in relation to itsstipe, expanding in volume as it matures. The skin of the cap is dry, matte and can be coloured from maroon to chocolate brown with a reddish tint.[18] It is thicker than otherporcini-like boletes and is gelatinous.[11] These characteristics distinguish it visually from relatives such asBoletus edulis,B. reticulatus andB. aereus. The young, immature cap may have a pale pink colour and a white, powdery flush.
As with all boletes, the size of thefruiting body can vary greatly. The cap diameter can be as much as 40 centimetres (16 inches), the stem height 25 cm (10 in) and stem diameter 16 cm (6+1⁄4 in).[18] Measuring4 to 10 cm (1+1⁄2 to 4 in) tall by3 to 8 cm (1+1⁄4 to3+1⁄4 in) wide, the bulbous stipe is often large, swollen and imposing, bearing a network pattern, much coarser in this species than other porcinis.[11] The overall colour may have an orange-red tinge which is more obvious in the lowest parts, although this is also common in other species. Like other boletes,B. pinophilus has small pores on the underside of its cap rather than gills. These are coloured white at first, becoming yellow with age and olive-brown at full maturity. Thespores are cylindric-ellipsoid, smooth, with oil drops and dimensions 15.5–20 by 4.5–5.5 μm. They produce an olive-brownspore print.[18]
Boletus pinophilus is the rarest of the porcini-like mushrooms in Europe, though is found across temperate regions.[5] It is found in Britain,[18] where it is more common in Scotland, and in France, where it is more common in the south,[19]Leningrad Oblast andVologda Oblast in Russia,[20] and Ukraine.[21] The bolete is consideredvulnerable in theCzech Republic.[22] It extends intoAsia Minor and southwestern Asia,[5] specifically as far as thePerm Krai in central Russia,[23] andIrkutsk Oblast in Siberia.[20] It is also found in exoticpine plantations (such asPinus sylvestris) in eastern North America, Mexico, Chile, South Africa and New Zealand.[5] Native populations from China and North America have been mostly confirmed as other distinct species.[5]
B. pinophilus formsectomycorrhizal relationships insymbiosis withpine (Pinus) species such as stone pine (P. cembra), black pine (P. nigra), Corsican pine (P. nigra subsp.laricio), cluster pine (P. pinaster), Monterey pine (P. radiata), Scots pine (P. sylvestris) andP. uncinata, as well as European silver fir (Abies alba) and European spruce (Picea abies).[5] It can therefore be located wherever those trees grow, particularly with Scots pine in Britain,[24] preferring the poor,acidic, and sandy soils associated withconiferous forests. It appears to favourPinus, while the form of the mushroom occurring in association withAbies andPicea has been labeledB. pinophilus var.fuscoruber.[11] However, it is not confined toconiferous trees and may also be found fruiting indeciduous forests, such as under chestnut trees (Castanea sativa),[19] oak (Quercus), beech (Fagus sylvatica), and possibly birch (Betula species), and hornbeam (Carpinus).[5]
Fruiting bodies can occur singly, or in small groups throughout the summer and autumn months, although they are known to appear as early as April in Italy.[25] A 2007 field study on four species of boletes revealed little correlation between the abundance of fruit bodies and presence of itsmycelia below ground, even whensoil 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 appear to be more complex than previously thought.[26]
Boletus pinophilus isedible and may be used fresh, preserved, dried and cooked in a manner similar to that of other edibleboletes.[27][28] It is highly regarded and can be quite expensive in central Mexico, and is often sold dried there.[29] The flesh is white, soft in mature specimens and does not change colour upon bruising. The taste and smell is pleasant.[27] People ofLa Malinche have likened the flavour to pork and pork crackling.[29] It is easily misidentified as the porciniB. edulis, due to the similar habitat and appearance.[30] It is a highly regarded food item, especially across the southern European regions of Portugal, theBasque Country andNavarre in Spain, France, Italy,Bulgaria andSerbia.[31] In the vicinity ofBorgotaro in the Province of Parma of northern Italy, the four speciesB. edulis,B. aereus,B. reticulatus, andB. pinophilus have been recognised for their superior taste and officially termedFungo di Borgotaro. Here, these mushrooms have been collected and exported commercially for centuries.[32] It is a commonly eaten mushroom in Turkey, especially in theMarmara and WesternBlack Sea regions, and is exported to Europe.[33] It is sold commercially in Finland.[34]
Fresh mushrooms are up to 90% water, and rich in carbohydrates.[31] Unsaturated alcohols are a major component of the aroma of porcini mushrooms;1-Octen-3-ol,2-octen-1-ol,3-Octanone,(E)-2-octenal,oct-1-en-3-one and1,7,7-trimethyl-heptan-2-one,2-propenoic acid and1,3-octadiene are the main volatile compounds inB. pinophilus.[33]B. pinophilus is known to be abioaccumulator of the heavy metalsmercury,cadmium andselenium.[16][35] To reduce exposure, authorities recommend avoiding mushrooms from polluted areas such as those near mines, smelters, roadways, incinerators and disposal sites. Furthermore, pores should be removed as they contain the highest concentrations of pollutants.[36]
Media related toBoletus pinophilus at Wikimedia Commons