Bronze Bolete

The cap is hemispherical to convex, reaching 15–20 cm (6–8 in) in diameter, although specimens of 40 cm (16 in) have been found in some cases. Slightly velvety, it is dark brown when young, greyish-brown, violet brown, or purple brown, often with copper, golden, or olivaceous patches. The stipe is 5–15 cm (2–6 in) long and 2–5 cm (3⁄4–2 in) thick, usually shorter than the cap diameter, initially barrel shaped but gradually becoming club shaped and tapering at the base. The stipe is white then brown, chestnut, or reddish brown in colour, covered in a brown or concolorous reticulation. As with other boletes, there are tubes rather than gills on the underside of the cap. The tube openings—known as pores—are small and rounded. Whitish when young, they slowly become yellowish or greenish yellow at maturity, and can turn wine coloured with bruising. The tubes themselves are initially white, later becoming yellowish or olivaceous. The thick flesh is white, exudes a robust and pleasant smell reminiscent of hazelnuts, and has a mild sweet taste. The spores are spindle shaped and measure 10.5–19 by 4–7 μm. The pileipellis is a trichodermium of interwoven septate hyphae, with long cylindrical cells.

Similar species. Boletus reticulatus is very similar to B. aereus, also occurring during the summer months under broad-leaved trees. …

The distribution and abundance of Boletus aereus varies greatly. Found mainly in central and southern Europe as well as north Africa, this species is rare in colder climates such as England. It is classified as a vulnerable species in the Czech Republic and has been placed on a provisional Red List of endangered species of Montenegro. Nevertheless, the fungus can be locally abundant; it is the most common bolete in the woodlands of Madonie Regional Natural Park in northern Sicily. Boletus aereus has been reported from several other island ecosystems across the Mediterranean, such as Corsica, Cyprus, Lesvos, and Naxos. Mushrooms are mostly found during hot spells in summer and autumn, growing in mycorrhizal association with various broad-leaved trees and sclerophyllous shrubs, especially oak (Quercus), beech (Fagus), chestnut (Castanea), strawberry trees (Arbutus), treeheath (Erica), and rockrose (Cistus), showing a preference for acidic soils. Roadsides and parks are common habitats. The cork oak in particular is an important symbiont, and the distribution of B. aereus aligns with the tree across Europe and North Africa. The ectomycorrhizae that B. aereus forms with sweet chestnut (Castanea sativa) and downy oak (Quercus pubescens) have been described in detail. …

A choice edible species, B. aereus is highly appreciated in Southern Europe for its culinary qualities and is considered by many to be gastronomically superior to B. edulis. In the vicinity of Borgotaro in the Province of Parma of northern Italy, the four species B. edulis, B. aereus, B. reticulatus (formerly known as B. aestivalis), and B. pinophilus have been recognised for their superior taste and officially termed Fungo di Borgotaro. Here, these mushrooms have been collected and exported commercially for centuries. Throughout Spain, it is one of the wild edible fungi most commonly collected for the table, particularly in Aragon, where it is harvested for sale in markets. It is also popular in Navarre, Spain, Basque Country, France, and Greece. When collected, the skin of the cap is left intact, and dirt is brushed off the surface. Pores are left unless old and soft. Boletus aereus is especially suited for drying, a process which enhances its flavour and aroma. Like other boletes, the mushrooms can be dried by being sliced and strung separately on twine, then hung close to the ceiling of a kitchen. Alternatively, the mushrooms can be dried by cleaning with a brush (washing is not recommended), and then placed in a wicker basket or bamboo steamer on top of a boiler or hot water tank. Once dry, they are kept in an airtight jar. …