Boletus luridiformis, formerly known as Boletus erythropus, is a wild mushroom of the bolete family

Boletaceae

Boletaceae are a family of mushrooms, primarily characterized by developing their spores in small pores on the underside of the mushroom, instead of gills, as are found in agarics. Nearly as widely distributed as agarics, they include the Cep or King Bolete , much sought after by mushroom hunters...

, all of which have tubes and pores, instead of gills beneath their caps. It is found in Northern Europe

Northern Europe

Northern Europe is the northern part or region of Europe. Northern Europe typically refers to the seven countries in the northern part of the European subcontinent which includes Denmark, Estonia, Latvia, Lithuania, Norway, Finland and Sweden...

, and North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, and is sometimes commonly known as the Dotted Stem Bolete. Although edible when cooked, it can cause gastric upset when raw and can be confused where the two species coincide with the poisonous Boletus satanas , which has a paler cap.

Taxonomy

Boletus luridiformis was originally described by Christian Hendrik Persoon

Christian Hendrik Persoon

Christiaan Hendrik Persoon was a mycologist who made additions to Linnaeus' mushroom taxonomy.-Early life:...

 in 1796 as Boletus erythropus - a name since reduced to synonymy - which derived its specific name from the Greek

Ancient Greek

Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 ερυθρος ("red") and πους ("foot"), referring to its red coloured stalk. Its French name, bolet à pied rouge or 'red-foot bolete' is a literal translation.

Description

Boletus luridiformis is a large solid fungus with a bay-brown hemispherical to convex cap

Pileus (mycology)

The pileus is the technical name for the cap, or cap-like part, of a basidiocarp or ascocarp that supports a spore-bearing surface, the hymenium. The hymenium may consist of lamellae, tubes, or teeth, on the underside of the pileus...

 that can grow up to 20 cm (8 in) wide, and is quite felty initially. It has small orange-red pores that become rusty with age, and bruise blue to black. The tubes are yellowish-green, and become blue quickly on cutting. The fat, colourful, densely red-dotted yellow stem

Stipe (mycology)

thumb|150px|right|Diagram of a [[basidiomycete]] stipe with an [[annulus |annulus]] and [[volva |volva]]In mycology a stipe refers to the stem or stalk-like feature supporting the cap of a mushroom. Like all tissues of the mushroom other than the hymenium, the stipe is composed of sterile hyphal...

 is 4–12 cm (2–5 in) high, and has no network pattern (reticulation). The flesh stains dark blue when bruised; broken, or cut. There is little smell. The spore dust is olive greenish-brown.

The similar Boletus luridus

Boletus luridus

Boletus luridus, commonly known as the lurid bolete, is a fungus of the bolete family, found in deciduous woodlands in Europe and eastern North America. Fruiting bodies arise in summer and autumn and may be common. It is a solid bolete with an olive-brown cap, orange pores and stout ochre stem...

has a network pattern on the stem, and seems to prefer chalky soil.

Boletus satanas also has a stem network, and a very pale whitish cap.

Distribution and habitat

The fungus grows in deciduous

Deciduous

Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 or coniferous woodland, in summer and autumn, in Europe. It is often found in the same places as Boletus edulis

Boletus edulis

Boletus edulis, commonly known as penny bun, porcino or cep, is a basidiomycete fungus, and the type species of the genus Boletus. Widely distributed in the Northern Hemisphere across Europe, Asia, and North America, it does not occur naturally in the Southern Hemisphere, although it has been...

. It is also widely distributed in North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

, and is especially common under spruce

Spruce

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 regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...

 in its range from Northern California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 to Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

. In Eastern North America it grows with both soft, and hardwood trees. It seems to prefer acid soils.

Toxicity

Mild tasting, Boletus luridiformis is edible after cooking, though caution is advised as it resembles other less edible blue-staining boletes, and should thus be avoided by novice mushroom hunters.