Boletus edulis is an edible basidiomycete mushroom. Most commonly known as porcini (from the plural of its Italian name porcino), it has a number of common names, including cep (from its Catalan name cep or its French name cèpe, although the latter is a generic term applying to several species), king bolete and penny bun.
The fruiting body is a large imposing mushroom the cap of which may reach 250NaN0 in diameter and 11NaN1 in weight. Symbiotic, it forms an ectomycorrhizal association with pine and is found in pine forests and plantations in autumn.
Highly prized, Boletus edulis is commercially sold fresh in autumn in central and southern Europe but is also dried and distributed worldwide.
Boletus edulis was first described in 1783 by the French botanist Pierre Bulliard and still bears its original name. Previously, the starting date of fungal taxonomy had been set as January 1 1821, the date of the works of the 'father of mycology', Swedish naturalist Elias Magnus Fries, which meant that the name required sanction by Fries (indicated in the name by a colon) to be considered valid as Bulliard's work preceded this date. Thus, it was written Boletus edulis Bull.:Fr. However, a recent revision of the International Code of Botanical Nomenclature in 1987 set the starting date at May 1, 1753, the date of publication of Linneaus' seminal work. Hence the name is no longer sanctioned.
Early alternate names include Boletus solidus by James Sowerby in 1809 and Gray's Leccinum edule. It is the first named and type species of the genus Boletus, the generic name derived from the Latin term Bōlētus 'mushroom' from the Ancient Greek βωλιτης, ultimately from bōlos/βωλος 'lump' or 'clod'. However, the βωλιτης of Galen is thought to have been the much prized Amanita caesarea.
The French name cèpe, or more fully cèpe de Bordeaux, is derived from the Gascon cep 'trunk' for its fat stalk. The name porcini meaning 'piglets' in Italian, as the young fruiting bodies resemble little piglets. A similar idea saw them called suilli by the Ancient Romans. The English penny bun and German Steinpilz 'stone mushroom' also refer to their rounded brownish shape. However in Austria it is called "Herrenpilz", the 'gentleman's mushroom'. They are known as hed tab tao Thai: เห็ดตับเต่า in Thai.
The mushroom is known as Ontto txuri or "the blond" in Basque, hřib pravý (Czech), cep (Catalan), vargánya (Hungarian), vrganj (Croatian), borowik szlachetny or prawdziwek (Polish), baravykas (Lithuanian), белый гриб "white mushroom" or боровик (Russian), dubák or hríb smrekový (Slovakian), jurček or jesenski goban (Slovenian), hrib or mânătarcă (Romanian), manatarka (Bulgarian), herkkutatti or "delicious bolete" (Finnish), harilik kivipuravik or "common bolete" (Estonian), baravika (Latvian), Karljohan after King Charles XIV John) or stensopp (Swedish), steinsopp (Norwegian), Karl Johan or spiselig rørhat (Danish), eekhoorntjesbrood "little squirrels' bread" (Dutch), vrganj (Serbian), 牛肝蕈 or "beef liver mushroom" (Traditional Chinese). It is also known as khubz el a'a or "crow's bread" in Arabic (Syria and Lebanon).
Several similar species are sometimes considered subspecies or forms of this mushroom. In France, in addition to Boletus edulis (or cèpe de Bordeaux), the most popular are
In parts of Colorado and New Mexico (and possibly elsewhere) there is a species Boletus barrowsii, named after its discoverer Chuck Barrows. It is mycorrhizal with Ponderosa pine and hence tends to grow in areas where there is less rainfall. Some find it as good as if not better than Boletus edulis.
The cap of this mushroom is 7–30 cm (3–12 in) broad at maturity, and slightly sticky. The color is generally reddish-brown fading to white in areas near the margin, and continues to darken as it matures. The stipe is 8–25 cm (3.5–10 in) in height, and up to 71NaN1 thick—rather large in comparison to the cap. The pores, which do not stain when bruised, are white in youth, fading to yellow and then to brown with age. The spore print is olive brown. Fully mature specimens can weigh about 11NaN1; a huge specimen collected on the Isle of Skye, Scotland, in 1995 bore a cap of 421NaN1, with a stipe 181NaN1 in height and 141NaN1 wide, and weighed in at 3.21NaN1.
However, the most appreciated by gourmets are the young small porcini, as the large ones often harbor maggots (insect larvae), and become slimy, soft and less tasty with age.
It is often confused with the very bitter and unpalatable Tylopilus felleus, but can be distinguished by the reticulation on the stalk; in porcini it is a whitish net-like pattern on a brownish stalk whereas it is a dark pattern on white in the latter. Porcini have whitish pores while the other has pink. If in doubt, tasting a tiny bit of flesh will yield a bitter taste. It can also look similar to the 'bolete-like' Gyroporus castaneus, which is generally smaller, and has a browner stem.
It has been proposed as one of the safest wild mushrooms to pick for the table as there are no poisonous species that closely resemble it. Perhaps the most similar would be the Devil's bolete (Boletus satanas), which is a similar shape though has a red stem and stains blue on bruising.
Cutting the stipe with a knife is alleged to run the risk of the left part rotting and destroying the mycelium. Fruiting bodies are instead collected by holding the stipe near the base and twisting gently. Peeling and washing are not recommended.
Boletus edulis can be found most commonly in Europe and North America. The mushroom can grow singly or in small clusters of two or three specimens. Its habitat consists of areas dominated by pine (Pinus spp.), spruce (Picea spp.), hemlock (Tsuga spp.) and fir (Abies spp.) trees. Not limited to these locations, the King Bolete is also found in hardwood forests containing oaks. It fruits from summer to autumn, following sustained rainfall. This mushroom can be found during the autumn in Syria and Lebanon. It has been recorded growing under Pinus and Tsuga in Sagarmatha National Park in Nepal.
Boletus edulis has been reported from the vicinity of Christchurch in New Zealand, where it is likely to have been somehow introduced . It has been growing plentifully in association with pine forests in the southern KwaZulu-Natal Midlands in South Africa for more than 50 years. It is not indigenous to the region, and is believed to have been brought there with the import of pine trees. 
As the name implies, Boletus edulis is edible, and a polled sample of people consider it superior to most other porcini in flavor and in texture—which is supported by its higher retail price. It is described as nutty and slightly meaty, with a smooth, creamy texture. This mushroom has a distinct aroma reminiscent of sourdough. It has a higher water content than other edible mushrooms. When dried, Boletus edulis has more protein than all other commonly consumed vegetables apart from soybeans. However, some of this content is indigestible, though digestibility is improved with cooking. Porcini are eaten and enjoyed raw, sautéed with butter, ground into pasta, in risotto, in soups, and in many other dishes. They are a feature of many cuisines, including Provençal, and Viennese. They are used in soups and consumed blanched in salads in Thailand.
Boletus edulis, along with Boletus badius and other boletes can be dried by stringing them separately on twine and hanging close to the ceiling of a kitchen. Alternatively they can be cleaned, but they should not be washed, and then placed in a wicker basket or bamboo steamer on top of a boiler or hot water tank. Once dry, they are best kept in an airtight jar. Drying them in the oven is inadvisable as it can result in them being cooked and spoiling. Importantly for commercial production, porcini retain their flavor after industrial preparation in a pressure cooker or after canning or bottling, and are thus useful for manufacturers of soups or stews. The addition of a few pieces of dried porcini can significantly add to flavor.
According to official figures, around 3000 tons were sold in France, Italy and Germany in 1988. However, the true amount consumed far exceeds this as collecting and informal sales are not included. They are widely exported and sold in dried form, reaching countries where they do not occur naturally, such as Australia. A 1998 survey estimates between 20,000 and 100,000 tons are consumed worldwide. It is sold commercially in Finland.
As with other strictly mycorrhizal fungi, Boletus edulis has eluded attempts to cultivate it.
. Jane Grigson. The Mushroom Feast. 8. 1975. Penguin. London. 0-14-046-273-2.
. Antonio Carluccio. 2003-10-17. The Complete Mushroom Book. Quadrille. 36–38. 978-1-844-00040-1.