User:Sasata/Boletus luridiformis

Boletus luridiformis, formerly known as Boletus erythropus, is a fungus of the bolete family, all of which produce mushrooms with tubes and pores beneath their caps. It is found in Northern Europe and North America, and is 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 as in 1795 Boletus erythropus by Christian Hendrik Persoon, who noted that it appeared with Boletus luridus and distinguished it from that species by its shorter stockier stipe, which lacks reticulation. This specific name is derived from the 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.

This name has been since reduced to synonymy -

German naturalist Friedrich Wilhelm Gottlieb Rostkovius gave the mushroom its current binomial name in 1844.

It is also called spotted-stem bolete.

Genetic analysis published in 2013 shows that B. luridiformis and many (but not all) red-pored boletes are part of a dupainii clade (named for Boletus dupainii), well-removed from the core group of Boletus edulis and relatives within the Boletineae. This indicates that it will most likely be placed in a new genus.

Description
Boletus luridiformis is a large solid fungus with a bay-brown hemispherical to convex cap that can grow up to 20 cm wide, and is quite felty initially. It has small orange-red pores that become rusty with age. The tubes are 1-3 cm long and olive- to greenish-yellow. All parts of the fruit body immediately become dark blue quickly on cutting or bruising. The fat, colourful, densely red-dotted yellow stem is 4–12 cm (2–5 in) high, and has no network pattern (reticulation). The red colour is so pervasive that it gives the impression the fruit body would have red flesh. The firm flesh is yellow throughout the fruit body and stains dark blue when bruised; broken, or cut, but can fade again to yellow. There is little smell. The spore dust is olive greenish-brown. The spores are 11-19 m long and spindle-shaped.

The taste is mild, with some acidity.

The similar Boletus luridus has a network pattern on the stem, and seems to prefer chalky soil.

The poisonous Boletus satanas also has a stem network, and a very pale whitish cap. The inedible and bitter B. calopus has a pale cap and yellow pores. B. luridiformis also stains a darker much more intense blue than either of these species.

Boletus queletii has a yellow stipe.

Distribution and habitat
Boletus luridiformis is found in Europe, North Africa, Asia and North America. The fungus grows in deciduous or coniferous woodland, in summer and autumn, in Europe. It is often found in the same places as Boletus edulis. It is also widely distributed in North America, and is especially common under spruce in its range from Northern California to Alaska. In Eastern North America it grows with both soft, and hardwood trees. It is more frequently encountered under beech and fir in Europe, as well as oak. It seems to prefer acid soils, and often is found with Boletus edulis. It can also be found on grassy forest verges, moors and among ferns such as bracken. It is found in hilly, mountainous and even subalpine regions.

Fruit bodies generally occur singly.

Isolated late specimens may be found in late winter.

Edibility
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. It is rarely affected by maggots. It is highly regarded by some, and is recommended for soups and cooking mixed with other boletes. However the dark colour of the flesh can be off-putting. Eaten raw or undercooked, it can cause vomiting.