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Birch Polypore - Fomitopsis betulina

Birch Polypore - Fomitopsis betulina

Main features

  • Found on living, dead or dying Birch

  • Fruits in Summer and Autumn, but old fruit bodies can be found all year

  • Has a large cap reaching 25cm wide and 6cm thick

  • Several fruits often found on same host tree

  • Cap starts off as a white ball bursting through the bark before turning grey-brown

  • Cap is kidney-shaped

  • Has white pores that buff with age

  • No real discernible stem

  • Smell pleasant and mild

  • Flesh white, firm and soft, toughening with age

  • Spores are white

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Birch Polypore - Fomitopsis betulina

Inedible mushroom - novice identification

Other common names: Razor Strop Fungus, Swiss Army Knife Fungus, Birch Bracket


Scientific name meaning: Fomitopsis has Latin origins and means "looks like Fomes", another type of bracket fungus. Betulina is also Latin, and means associated with Birch, which this fungus grows on

Season - when will I find it? Summer to Autumn, but old fruits can be found all year

Habitat - where will I find it? Growing on living, dying and dead Birch trees

Description - what does it look like? 

Growth: Birch Polypore Fungus grows both parasitically and as a saprobe on living dead or dying Birch. Often several fruits are found on the same tree

Cap: Starts off as a white ball bursting through the bark. The cap then become brown grey and kidney-shaped. It can reach up to 25cm wide and 6cm thick

Pores: The pore surface is white, turning buff with age

Stem: No real discernible stem

Flesh: Soft, firm and white at first, toughening with age

Smell: Mild and pleasant

Spore colour: White

Possible lookalikes Could be confused with the Dryad's Saddle (Polyporus squamosus), but this has brown scales resembling a bird's wing, and Birch Polypore grows on Birch

Use as a food Birch Polypore is considered inedible due to its bitter taste. However, some drink it as a medicinal tea

Use in medicine Birch Polypore is known to have some antimicrobial, antiviral, antiparasitic, styptic and even anticancer properties. Its potential use in medicine is being increasingly researched.

If you are suffering from any ailment or need medical advice, please see your General Practitioner

Other uses The porous surface can be used as a natural plaster, and was used by barbers to strop razors. If dried out, can be used as a form of kindling 

Hazards None known by author

Importance to other species A food source of slugs and snails

Always stay safe when foraging. You need to be 100% sure of your identification, 100% sure that your foraged item is edible, and 100% sure that you are not allergic to it (it is good practice to always try a small amount of any new food you are consuming). If in doubt, leave it out!

Young Birch Polypore - Fomitopsis betulina
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