Fomitopsis betulina (Bull.) B.K.Cui
M.L.Han & Y.C.Dai
Piptoporus betulinus (Bull.) P. Karst.
Agarico-pulpa pseudoagaricon Paulet
Boletus suberosus L.
Boletus betulinus Bull.
Polyporus betulinus (Bull.) Fr.
Ungulina betulina (Bull.) Pat.
Birch polypore, razor strop
The birch polypore is native to temperate regions worldwide. Its habitat is birch trees, especially white birch. They are tougher than they look: barbers once sharpened their razors on leathery strips cut from these mushrooms.
Fruits: These bracket fungi extend from the sides of dead or dying birches. (This is kind of amazing, since the bark of white birches is so durable that an entire downed tree rots before the bark degrades.) The fruits are whitish or gray-brown on top and cream-colored below, and kidney-shaped. As they mature, they become flatter and browner on top, and tan beneath. Undersides are dense clusters of pores ¹/₃₂-⅛" (1.5-5 mm) deep. The fruits have a strong pleasant mushroomy odor.
Spores: Spores are cylindrical to ellipsoidal, smooth, and 3-6 µm × 1.3-2 µm. Spore prints are white.
Edibility: Tough and bitter, these are technically edible but not desirable.
Medical: The antibiotic piptamine is obtained from this fungus. Piptamine shows antimicrobial activity against some Gram positive bacteria, yeasts (Candida albicans) and fungi. They are a natural astringent, used to help stop bleeding.
Fomitopsis betulina on Michael Kuo's MushroomExpert.com
Fomitopsis betulina on www.first-nature.com
Fomitopsis betulina on www.mushroomknowhow.com
Fomitopsis betulina on www.ediblewildfood.com
Fomitopsis betulina on Wikipedia
Fomitopsis betulina on link.springer.com
Fomitopsis betulina description by Thomas H. Kent, last updated 7 Nov 2020.