''Leccinum scabrum'', commonly known as the rough-stemmed bolete, scaber stalk, and birch bolete, is an

edible mushroom Edible mushrooms are the fleshy and edible fruit bodies of several species of macrofungi (fungi which bear fruiting structures that are large enough to be seen with the naked eye). They can appear either below ground (hypogeous) or above ground ...

in the family

Boletaceae The Boletaceae are a family of mushroom-forming fungi, primarily characterised by small pores on the spore-bearing hymenial surface (at the underside of the mushroom), instead of gills as are found in most agarics. Nearly as widely distributed ...

, and was formerly classified as ''Boletus scaber''. The birch bolete is widespread in Europe, in the

Himalayas The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over ...

in Asia, and elsewhere in the Northern Hemisphere, occurring only in mycorrhizal association with

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 3 ...

trees. It fruits from June to October. This mushroom is also becoming increasingly common in Australia and New Zealand where it is likely introduced.

Description

The cap is wide. At first, it is hemispherical, and later becomes flatter. The skin of the cap is tan or brownish, usually with a lighter edge; it is smooth, bald, and dry to viscid. The pores are whitish 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 long and wide, slim, with white and dark to black flakes, and tapers upward. The basic

mycelium Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates in ...

is white. The

flesh Flesh is any aggregation of soft tissues of an organism. Various multicellular organisms have soft tissues that may be called "flesh". In mammals, including humans, ''flesh'' encompasses muscles, fats and other loose connective tissues, but ...

is whitish, sometimes darkening following exposure. In young specimens, the meat is relatively firm, but it very soon becomes spongy and holds water, especially in rainy weather. When cooked, the meat of the birch bolete turns black. ''Leccinum scabrum'' has been found in association with ornamental birch trees planted outside of its native range, such as in

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the ...

Habitat and distribution

''Leccinum scabrum'' is a European species that has been introduced to various areas of the world, mostly appearing in urban areas. In New Zealand, it associates solely with ''

Betula pendula ''Betula pendula'', commonly known as silver birch, warty birch, European white birch, or East Asian white birch, is a species of tree in the family Betulaceae, native to Europe and parts of Asia, though in southern Europe, it is only found ...

''.

Uses

The birch bolete is edible but considered not to be worthwhile by some guides. It can be pickled in

brine Brine is a high-concentration Solution (chemistry), solution of salt (NaCl) in water (H2O). In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawater, on the lower end of that of ...

vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation, converting simple sugars to ...

. It is used also in mixed mushroom dishes, fried or steamed. It is commonly harvested for food in Finland and Russia. A few reports in North America (New England and the Rocky Mountains) after 2009 suggest that Leccinums (birch boletes) should only be consumed with much caution.

Similar species

Several different species of ''

Leccinum ''Leccinum'' is a genus of fungi in the family Boletaceae. It was the name given first to a series of fungi within the genus '' Boletus'', then erected as a new genus last century. Their main distinguishing feature is the small, rigid projections ...

'' 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.

References

External links

Pilzgalerie: Leccinum scabrum (Birkenpilz)
{{Taxonbar, from=Q628977 scabrum Edible fungi Fungi described in 1783 Fungi of Europe Fungi of New Zealand Fungi of North America Taxa named by Jean Baptiste François Pierre Bulliard