It’s very rare that I do not see one of these bracket fungus when I’m out and about on a forage. They grow quite large and are around all year. It would be hard to miss one.
The Birch Polypore or Razorstrop fungus (Piptoporus betulinus) is an extremely common polypore fungus. As the name suggests, it is found exclusively on birch trees.
At maturity they are typically semicircular or kidney shaped as they grow outwards from the tree body. Shapes and sizes may differ a little but generally this is the norm. As I mentioned earlier, they can grow to a good size – between 20 – 30cm across and 8cm thick! They’re quite a sight to behold when they get to this size.
The colour is that of pure white (when younger) and as it matures it changes to a dull grey or tawny brown. It’s smooth surface often cracks, showing white flesh underneath. The consistency is spongy or slightly rubbery to the touch. These fruiting bodies can usually last from one year into the next, that is why you can see them all of the time over the winter months.
On the underside the pored surface is smooth and pure white, but over time this gets marked with dark patches from age and/or insect attack.
I know what you’re thinking though. Is this fungus edible? Well, unfortunately not. It actually smells quite pleasant but it’s taste is quite bitter. It’s a shame, I know.
At least it had it’s uses even as far back as 5,300 years ago! In 1991 “Ötzi the Iceman” (Europe’s oldest natural human mummy) was discovered by German tourists in the Alps. Found in his possession were two species of polypore mushroom. One of which was the Birch Polypore (for medicinal use) which is known to have antibacterial properties. It could have also have been used to sharpen blades or tools – hence the name ‘Razorstrop’.