Leccinum scabrum

The Birch bolete (Leccinum scabrum) is an edible mushroom, deriving its common name from its old scientific name of Boletus scaber. It belongs to the family of boletes and occurs only in symbiosis (mycorrhiza) with birches. The birch bolete is widespread in Europe and grows from June to October.

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Description

The pileus is 5–15 cm (2–6 in.) wide. At first it is hemispherical and later becomes flatter. The skin of the cap is light gray-brown to reddish gray-brown, later often more or less brown, smooth, bald, dry, and rather slimy when damp.

The pores are white at a young age, later gray. In older specimens the pores on the pileus can bulge out, while around the stipe they dent in strongly. The pore covering is easy to remove from the skin of the pileus.

The stipe is 5–15 cm (2–6 in.) long and 1–3.5 cm (³⁄₈–1³⁄₈ in.) wide, slim, with white and dark to black flakes, and tapers upward. The basic mycelium is white.

The flesh is whitish, later more gray-white and does not change color when broken. In young specimens the meat is relatively firm, but it very soon becomes spongey and holds water, especially in rainy weather. When cooked, the meat of the birch bolete turns black.

Similar species

Several different species of Leccinum mushrooms are found in mycorrhiza with birches, and can be confused by amateurs and mycologists alike. L. variicolor has a bluish stipe. L. oxydabile has firmer, pinkish flesh and a different pileus skin structure. L. melaneum is darker in color and has yellowish hues under the skin of the pileus and stipe. L. holopus is paler and whitish in all parts.

Uses

The birch bolete is edible and is especially enjoyable pickled in brine or vinegar. It is used also in mixed mushroom dishes, fried or steamed. Experience shows that the extract of the birch bolete may be helpful in cases of stomach trouble.

References

• Kallenbach: Die Röhrlinge (Boletaceae), Leipzig, Klinkhardt, (1940-42)
• Gerhardt, Ewald: Pilze. Band 2: Röhrlinge, Porlinge, Bauchpilze, Schlauchpilze und andere, (Spektrum der Natur BLV Intensiv), (1985)

This article incorporates text translated from the corresponding German Wikipedia article as of 3 February 2006.