| Leccinum scabrum | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Fungi |
| Division: | Basidiomycota |
| Class: | Agaricomycetes |
| Order: | Boletales |
| Family: | Boletaceae |
| Genus: | Leccinum |
| Species: | L. scabrum |
| Binomial name | |
| Leccinum scabrum | |
| Synonyms | |
| |
| Leccinum scabrum | |
|---|---|
| Mycological characteristics | |
 | Pores onhymenium |
 | Cap is convex |
 | Hymenium is adnate |
 | Stipe is bare |
 | Spore print is olive |
 | Ecology ismycorrhizal |
  | Edibility isedible butnot recommended |
Leccinum scabrum, commonly known as thebirch bolete,[1]rough-stemmed bolete, orscaber stalk, is a species of fungus in the familyBoletaceae. It was formerly classified asBoletus scaber.
The birch bolete is widespread in Europe, in theHimalayas in Asia, and elsewhere in theNorthern Hemisphere, occurring only inmycorrhizal association withbirch trees. This mushroom is also becoming increasingly common in Australia and New Zealand where it is likelyintroduced. It is anedible mushroom if only firm specimens are used and cooked thoroughly.
Thecap is 4–10 cm (1+1⁄2–4 in) wide and convex before flattening.[1] The skin of the cap is tan or brownish, usually with a lighter edge;[2] it is smooth, bald, and dry to viscid.[2]
The pores are whitish[2] 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.[citation needed] Thespore print is brown. Thespores measure 13–16 by 4–4.5 μm and are elliptical.[3]
Thestipe is 5–15 cm (2–6 in) long and1–3.5 cm (3⁄8–1+3⁄8 in) wide and slim, with white and dark to black flakes; it tapers upward.[2] The basicmycelium is white.
Theflesh is whitish, sometimes darkening following exposure.[2] In young specimens, the meat is relatively firm,[2] but it very soon becomes spongy and holds water, especially in rainy weather. When cooked, the meat turns black.[citation needed]
Several different species ofLeccinum mushrooms are found in mycorrhiza with birches, and can be confused by amateurs andmycologists alike.L. holopus is paler and whitish in all parts.L. alaskanum, common with birch in Alaska, has a dark and light, streaked or mottled cap.[1]L. variicolor has a bluish stipe.L. oxydabile has firmer, pinkish flesh and a different pileus skin structure.
Leccinum scabrum is a European species that has beenintroduced to various areas of the world, mostly appearing in urban areas.[2] In New Zealand, it associates solely withBetula pendula.[4] In North America, it can be found from June to September, except on the West Coast, where it appears from September to November.[3]
It grows in association with birch.[3] It has been found in association with ornamental birch trees planted outside of its native range, such as inCalifornia.[5]
The species isedible when firm,[1] but some guides consider it unworthwhile.[6] It can be cooked in various mushroom dishes[7] or be pickled inbrine orvinegar. It is commonly harvested for food in Finland and Russia.[8]
