It’s been a very long time since I blogged about this fascinating fungus, Birch polypore (Piptoporus betulinus), also known as Razorstrop fungus, because, as I explained in An essential piece of traveller’s kit (8 February 2016), barbers once used the hard surface of this fungus to sharpen their cut-throat razors.

Birch polypore is a rotter, literally; its powers of decomposition are strong, mostly acting on the wood of dead Birches (Betulinus species) but, as Pat O’Reilly writes in Fascinated by Fungi, it may also ‘be parasitic on weakened birches’. I found this lovely specimen feeding on a dead Birch in a Cardiff park earlier this week.