Porcini or Orange birch 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.

The cap is large: 6-20 cm across, hemispherical with an inrolled margin in young mushrooms, becoming convex with age, then flat and spread out. The color is bright orange, brick-yellow, rusty orange, more intense in young mushrooms and paler in old ones. The cap skin is roughly suede-like or slightly fibrous, a little slippery in wet weather. The skin does not peel off; ragged scraps of a leathery "curtain" often hang from the margin.

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.

Tubular hymenophore. The tubes are long (2-3 cm), grayish-white in young mushrooms, grayish-cream with age. They are not attached to the stem (they separate easily from the cap). The spore print is olive-brown. The pores are small and round.

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.

The stem is sturdy: 8-20 cm tall, 1.5-3 cm thick, cylindrical, thickened at the base and narrowing toward the top. Its color ranges from whitish to dirty gray, densely covered with dark gray or blackish scale-like fibers — a hallmark of the genus Leccinum. No ring.

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.

The flesh is thick, white, very firm and meaty in young mushrooms. When cut, it gradually darkens: it may first turn pinkish, then violet-gray, then black, and the stem base often turns bluish — a normal reaction of the species, not a sign of spoilage. It also darkens when cooked. The texture holds its shape well in the pan.

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.

A faint, pleasant mushroomy smell with a hint of fresh forest litter. The taste is mild, delicate, typically mushroomy. No sharp or unpleasant notes.