The cap of this mushroom is 7–30 cm (3–12 in) broad at maturity. Slightly sticky to touch, it is convex in shape when young and flattens with age. The colour is generally reddish-brown fading to white in areas near the margin, and continues to darken as it matures. The stipe, or stem, is 8–25 cm (3.5–10 in) in height, and up to 7 cm (2.8 in) thick—rather large in comparison to the cap; it is club-shaped, or bulges out in the middle. It is finely reticulate on the upper portion, but smooth or irregularly ridged on the lower part. The under surface of the cap is made of thin tubes, the site of spore production; they are 1 to 2 cm (0.4 to 0.8 in) deep, and whitish in colour when young, but mature to a greenish-yellow. The angular pores, which do not stain when bruised, are small — roughly 2 to 3 pores per millimetre. In youth, the pores are white and appear as if stuffed with cotton (which are actually mycelia); as they age, they change colour to yellow and later to brown. The spore print is olive brown. The flesh of the fruit body is white, thick and firm when young, but becomes somewhat spongy with age. When bruised or cut, it either does not change colour, or turns a very light brown. Fully mature specimens can weigh about 1 kg (2.2 lb); a huge specimen collected on the Isle of Skye, Scotland, in 1995 bore a cap of 42 cm (16.5 in), with a stipe 18 cm (7.1 in) in height and 14 cm (5.5 in) wide, and weighed 3.2 kg (7.1 lb).
The mushroom's habitat consists of areas dominated by pine (Pinus spp.), spruce (Picea spp.), hemlock (Tsuga spp.) and fir (Abies spp.) trees, although other hosts include chestnut, chinquapin, beech, Keteleeria spp., Lithocarpus spp., and oak. In California, porcini have been collected in a variety of forests, such as coastal forests, dry interior oak forests and savannas and interior high-elevation montane mixed forests, to an altitude of 3,500 m (11,500 ft). In northwestern Spain, they are common in scrublands dominated by the rock rose species Cistus ladanifer and Halimium lasianthum. Boletus edulis has a cosmopolitan distribution, concentrated in cool-temperate to subtropical regions. It is common in Europe—from northern Scandinavia, south to the extremities of Greece and Italy—and North America, where its southern range extends as far south as Mexico. It is well known from the Borgotaro area of Parma, Italy, and has PGI status there. The European distribution extends north to Scandinavia and south to southern Italy and Morocco. In China, the mushroom can be found from the northeastern Heilongjiang Province to the Yunnan-Guizhou Plateau and Tibet. It has been recorded growing under Pinus and Tsuga in Sagarmatha National Park in Nepal, as well as in the Indian forests of Arunachal Pradesh. In West Asia, the species has been reported from the northwest forests of Iran.
Found in Cades Cover Area.