Bulging bracket! – The Birch Polypore

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.

Razorstrop Fungus

Typical semi-circular/kidney shape of the Birch Polypore

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’.

Polypore fungus

In the images above are some very young Birch Polypores growing out of from the bark of a fallen silver birch tree.

7 replies
  1. Neal
    Neal says:

    Just thought I’d say that these mushrooms are edible meaning that they can be eaten but just taste bad. They can also be made into Medicinal teas and have very similar properties to the famous Reishi mushroom used in TCM. I recently found some and will be making a alcohol extraction with the mushroom. Like your site take care.

    Have a look at my site for articles on Medicinal mushrooms :)

    • J C Harris
      J C Harris says:

      Very interesting information Neil. It’s great to discover their other uses – especially health benefits. Had a look at the website. Great stuff. Keep up the good work there.

    • merle
      merle says:

      right on Neal, but I have to say, they don’t taste bad. I’d picked a few, and a friend said they are medicinal, looked it up, they are also an antiínflammatory, so I was planning to fry them up, and found out they are tasty when young and white. but i often find the wiki states certain mushrooms smell and taste bad, when it clearly depends on who is tasting and smelling.

  2. Gill Cotterill
    Gill Cotterill says:

    I’ve made paper from this polypore after a foraging walk. Unusual but different and worth the effort. I’m a card crafter so its good to work with something different.


Trackbacks & Pingbacks

  1. […] land, other trees follow within a few years. But even before that happens, fungi such as the birch polyphore (Piptoporus betulinus) photographed by my fellow blogger John Harris on the tree trunks. Indeed, birch woodland supports […]

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