Porcini or Royal bolete

Cap 7–30 cm across, spherical or hemispherical in young mushrooms, becoming cushion-shaped and spread out over time. The color varies from light brown to dark chestnut or reddish brown depending on light and forest type: caps are darker in spruce woods and lighter in pine forests.

The cap surface is dry, smooth or slightly wrinkled, and can be a little sticky in wet weather. The margin is even or slightly wavy, inrolled in young mushrooms. The skin doesn't peel.

Cap 5–15 cm, hemispherical in young mushrooms, then cushion-shaped and flattened-convex. Color pinkish raspberry, pinkish red, darkening with age to brownish red. Surface matte, slightly fibrous in dry weather, a little slimy in wet weather. The cap skin does not peel. The cap margin is rolled inward at first, then straightens out.

The hymenophore is tubular and separates easily from the cap flesh. In young mushrooms the tubes are white, later turning yellow; in mature ones they're yellow-green or olive. The pores are small, round, uniform in color and don't change color when pressed.

Hymenophore tubular, free or slightly notched at the stem. Lemon yellow, turning ochre-yellow with age, olive in old mushrooms. Pores small and round. When pressed it may turn faintly blue or not change color at all — unusual for a bolete.

Stem massive, 5–20 cm tall and 3–10 cm thick, bulbous or club-shaped in young mushrooms, later cylindrical. Color from whitish to light brown. The surface is covered with a characteristic white or cream net pattern, most distinct in the upper part of the stem.

There's no ring and no volva. The base of the stem is often thickened.

Stem 5–14 cm tall, 2–6 cm thick, bulbous at the base, then cylindrical. Color lemon yellow to ochre-yellow, with a clearly visible fine net on the upper part (a hallmark of the genus Butyriboletus). Sometimes with a pinkish tinge at the base.

The flesh is dense, juicy and white, and doesn't change color when cut or damaged — this feature sets porcini apart from a number of poisonous lookalikes. In old fruiting bodies the flesh becomes spongy and yellowish.

The taste is mild, nutty and slightly sweet. The stem flesh is denser and more fibrous than the cap flesh.

Flesh lemon yellow, reddish under the cap skin, very firm and heavy. When cut, the color does not change or turns slightly blue in spots. This is another important diagnostic feature — most pink-capped boletes turn blue instantly and strongly.

The smell is pleasant, unobtrusive, mushroomy with light nutty notes. With cooking and drying the aroma intensifies and takes on a deep, rich woody, foresty character. It's for dried porcini that the mushroom is so valued in cooking — no other dried mushroom gives such a pronounced taste and smell.

Smell faint, pleasantly mushroomy, with notes of fresh hazelnut. Taste mild, sweetish, with no bitterness and no peppery notes.