BOLETUS AEREUS: CHARACTERISTICS, HABITAT, IDENTIFICATION, RECIPES - BIOLOGY - 2025

Boletus aereus is one of the main edible mushrooms of the Edules section that belongs to the Boletaceae family. Known as black fungus, it is a common wild species both in deciduous forests such as chestnut, beech and oak forests.

It is a convex hat fungus 15-25 cm in diameter, dark brown or almost black in color. The foot is thick, solid and bulging 6-12 cm high and dark brown in color. The firm, white and dense flesh has a pleasant aroma.

Boletus aereus. Source: Roberto1974 / Public domain

The black fungus is an edible mushroom par excellence, being very abundant in an uninterrupted way from spring to late autumn. However, it is easily confused with other less abundant Boletus species, such as B. edulis, B. pinophilus and B. reticulatus.

It is geographically distributed throughout the southern region of Europe and in North America, its population density depends on the altitude and latitude of each region. In the Iberian Peninsula it is located in the Sierra de Gata region in Extremadura, the north of Navarra and the Basque Country.

General characteristics

Group of Boletus aereus. Source: This image was created by user Davide Puddu (Davide Puddu) at Mushroom Observer, a source for mycological images.You can contact this user here.English - español - français - italiano - македонски - മലയാളം - português - +/− / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

Hat or cap

The hat is a fleshy structure, hemispherical in shape when young, convex when mature and flat with old age. The cuticle begins being velvety and dry, then it becomes smooth, dark brown or almost black, with time it opens and cracks easily.

The margins develop excessively or curved, at maturity it tends to take a curved plane. It is a large species that can measure between 15-25 cm in diameter, under certain conditions it can reach up to 35 cm in diameter.

Hymenio

The tubes are thin and elongated, whitish, yellowish or greenish with age, separated or adnate on the peduncle. Tight, rounded pores, the same color as tubes, tend to warp over time. The spindle-shaped spores of pale yellow or olive-green color measure between 12-16 x 4-6 microns.

Foot

It is a central, robust and solid structure, thickened at the base or cylindrical in shape in larger specimens, measuring 6-12 cm high by 3-8 cm in diameter. It is the same color as the hat, but paler with a very fine reticulum that covers the upper two-thirds.

Meat

Its meat is firm, dense and compact, softer with age, unchanging white during development. It has a pleasant flavor and aroma, when cut, it maintains its light color and does not oxidize or alter its smell.

Taxonomy

- Fungi kingdom

- Division: Basidiomycota

- Subdivision: Basidiomycotina

- Class: Agaricomycetes

- Order: Boletales

- Family: Boletaceae

- Section: Edules

- Genus: Boletus

- Species: Boletus aereus Bull. (1789)

Etymology

- Boletus: the name of the genus comes from the Greek «βωλος» which means «ball» in allusion to the globose shape of its hat.

- aereus: the specific adjective derives from the Latin «aes-aeris», which means «copper or bronze» because of the color of its hat.

Synonymous

- Boletus sykorae Smot.

- Tubiporus ustulatus Paulet

Boletus aereus cut. Source: JF Gaffard Jeffdelonge at fr.wikipedia / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

Habitat

The black fungus is a thermophilic species that prefers the Mediterranean climate, usually developing during the summer months and early fall. It grows on slightly acidic soils and is associated with various deciduous species of the Fagaceae family, mainly cork oaks, chestnut trees, holm oaks, beeches and oaks.

They are located in full sun exposure, which is why it is considered one of the easiest Boletus to locate in the field. It grows in open land and usually appear in groups of two or three specimens in a few square meters.

Its optimal requirements range between 12-22 ºC of annual average temperature, 600-1,000 mm of annual average precipitation, even 2,000 mm well distributed throughout the year. They are located at 500-1,300 meters above sea level, although they are frequent in medium and low mountain regions, even near sea level.

How to identify the

Mushrooms of the genus Boletus, which includes the species Boletus aereus, Boletus aestivalis, Boletus edulis, Boletus pinophilus and Boletus reticulatus tend to be confused at the field level. However, each species has its own peculiarities, location and time of development.

Boletus aereus

The hat is characterized by a chocolate-brown color with a tomentose appearance in hot and dry environments. It bears fruit from mid-July to November.

It grows under beech and oak groves, being less frequent in holm oaks and pine groves. In the same way, it emerges on heather, ferns, grasslands and litter.

Boletus aereus. Source: Susanne Sourell (suse) / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

Boletus aestivalis

The hat has a more or less intense brown color, with small barely visible scales. The cuticle is dull and velvety in appearance in hot and dry environments.

It bears fruit from mid-June to September. It grows under holm oaks, beech and oak groves. It emerges on grasslands and litter.

Boletus aestivalis. Source: BoletusAestivalis.JPG: Archenzoderivative work: Ak ccm / CC BY-SA (http://creativecommons.org/licenses/by-sa/3.0/)

Boletus edulis

The hat has a particular brown color with noticeably paler margins. In hot and dry environments, the cuticle appears moist, slimy and greasy. The light cream colored foot is covered by a white reticule. The meat is compact and whitish.

It bears fruit from mid-June to mid-November. It grows under chestnut, beech and oak groves, less frequently under holm oaks and pine groves. It emerges on grasslands and litter.

Boletus edulis. Source: H. Krisp / CC BY (https://creativecommons.org/licenses/by/3.0)

Boletus pinophilus

The hat and the foot have a particularly garnet or reddish hue. The cuticle is greasy and not very viscous in hot and dry environments. The foot has a cream-colored reticulum that covers the upper two-thirds of it. The meat is brown.

It bears fruit from mid-September to mid-November. It grows under chestnut, beech, pine and oak groves. It emerges among grasslands, ferns and litter.

Boletus pinophilus. Source: 2008-11-05_Boletus_pinophilus_Pilát _ & _ Dermek_27980.jpg: This image was created by user Irene Andersson (irenea) at Mushroom Observer, a source for mycological images.You can contact this user here.English - español - français - italiano - македонски - മലയാളം português - +/− derivative work: Ak ccm / CC BY-SA (https://creativecommons.org/licenses/by-sa/3.0)

Boletus reticulatus

Light ocher colored hat, less plush cuticle and the reticulum on the foot more prominent than the other species. The meat is matte white and cross-linked.

Boletus reticulatus. Source: George Chernilevsky / Public domain

Recipes

The Boletus aereus species is considered the best edible mushroom in the Edules section, thanks to its gastronomic quality it closely competes with the Boletus edulis species. In fact, the black mushroom has a compact, brown meat with a pleasant aroma, and it also maintains its texture for longer, being ideal for working in the kitchen.

- Mushroom cream

Ingredients

- 500 gr. mushroom

- 1 medium onion

- 1 liter of chicken or vegetable broth

- 75 ml of milk

- Extra virgin olive oil, salt and pepper to taste

Elaboration

- Wash all fresh mushrooms well and cut off the end of the stem. In case of using dehydrated mushrooms, place in warm water for an hour to rehydrate.

- Fry the onion in the olive oil until golden brown and add the chopped mushrooms, trying to save some mushrooms for decoration.

- Sauté all the ingredients profusely, avoiding burning, to prevent the cream from being too dark.

- Add the broth and boil for 10-12 minutes over high heat to concentrate the flavors.

- Rest the broth and blend conveniently until obtaining a thick cream.

- After blending, it is expected to obtain a light puree that is transferred to a saucepan, placed over a low heat and added the 75 ml of milk.

- Let it boil for 5 minutes until it thickens a little more.

- Milk can be substituted for liquid cream to obtain a thicker and more nutritious cream.

- Served hot in a bowl decorated with pieces of roasted mushrooms.

- Grilled boletus

Ingredients

- 300 gr of the black mushroom

- 50 ml of extra virgin olive oil

- 1 egg yolk

Elaboration

- Clean the mushrooms by removing the end of the stem, wash and dry with absorbent paper.

- Cut into more or less thick sheets.

- Sauté the mushrooms in the very hot olive oil until they turn an attractive golden color.

- Once removed from the pan, turn off the heat and place the yolk to cook with the residual heat.

- Serve the grilled mushroom fillets with the roasted yolk as a side.

Mushrooms are highly valued in gastronomy. Source: pixabay.com

- Sauteed Brussels sprouts and mushrooms

Ingredients

- 1-2 medium or large mushroom

- 125g Brussels sprouts

- 1 clove garlic

- 1 glass of white wine

- 1/2 teaspoon apple cider vinegar

- 1 teaspoon of honey

- 1/2 teaspoon soy sauce

- Extra virgin olive oil, black pepper, thyme, sage and salt to taste

Elaboration

- Wash the Brussels sprouts and blanch in boiling water for 1-2 minutes, drain, cool and cut in half.

- Peel and mince the garlic clove.

- Clean the fungi well, trying to eliminate the base of the trunk, chop and laminate finely.

- Brown the garlic in the hot oil, add the cabbages and sauté over high heat for 5 minutes, add the mushrooms together with the wine and mix well over low heat.

- Season with salt, pepper and aromatic herbs.

- Mix the apple cider vinegar, honey, soy sauce and olive oil in a bowl, add the sautéed mixture and serve hot.

References

1. Boletus aereus. (2019). Wikipedia, The Free Encyclopedia. Recovered at: es.wikipedia.org
2. Boletus aereus, the king of summer mushrooms (2019) The House of Mushrooms. Recovered in: lacasadelassetas.com
3. Colina, Z. (2019) Boletus. Our Flora. Recovered at: ourflora.com
4. Cuesta, J. and Jiménez, J. (2016) El Royo Mycological Association. Recovered at: amanitacesarea.com
5. The nine best recipes for cooking with boletus (2018) Direct to the Palate: The Taste of Life. Recovered at: directoalpaladar.com
6. Forest Mycology in Navarra - Micosylva Project (2010) Lur Geroa, SL. Gestión Ambiental Viveros y Repoblaciones de Navarra, SA (GAVRN).
7. Portillo, G. (2018) Boletus aereus. Gardening On. Recovered in: jardineriaon.com