Piptoporus betulinus – a find from today

Today’s journeys were fruitful on the fungal front: Daldinia concentrica, Fistulina hepatica (in a heavily rotted state), Ganoderma applanatum*, Ganoderma australe*, Laetiporus sulphureus (again in a rotted state, though also blitzed by an animal), Piptoporus betulinus, Porodaedalea pini, and Pseudoinonotus dryadeus were all finds. (* I strongly suspect both Ganoderma spp. mentioned were identified, given very distinct morphological differences between the sporophores). The topic of this post will be Piptoporus betulinus exclusively, as the sporophores I saw really raised my interest (in part, down to my newly-acquired Swiss Army Knife and its dissective powers).

Birch polypore really isn’t an uncommon site where birch can be found in woodland – rarely do I visit a woodland with birch and not see either active or more desiccated examples. However, it’s the colonisation strategy of the fungus that really enthralls me. Spores will gain entry via stem injury, and then attack the tree’s sapwood and heartwood once once the host is under stress – in woodlands, this may very well be induced by a birch’s poor ability to compete for light with maturing (typically) later-successional and / or slower-growing species such as oak, beech, chestnut, hornbeam, and ash. Once the host birch is stressed, the fungus will attack, creating a (quite wonderful in appearance) brown rot, and the stressed host will likely die very swiftly (if not fail a few metres up from the base). Birch polypore will then persist as a saprophyte – this is when, for me, the fun happens. Just look at the below photos.

Oh look – it’s a dead birch. And what’s on it? Birch polypore!

Looking upwards from the ground, we can identify five different sporophores (at all sides of the circumference) on this dead host from this angle.

Nearby, another dead birch acts as a host. Notice the trunk has fractured half way.

Taking a step back to view the host, we can see that the entire remaining stem is colonised – all the way down to the base. And we can now see that this dead birch failed initially up high on the stem, and has since (or even at the same time) failed beneath.

Given their local abundance, I took one back for a closer inspection. Here we can see the texture atop, and the dainty stalk.

…and the texture below. I can see a resemblance to desiccated Laetiporus sulphureus.

I then cut open, for the first time, this fungus’ sporophore. If I’m honest, I didn’t expect what I saw – an immaculate and pure white cross-section (the marks were from my blade), with but a tiny underside where the spores are released from. Pretty awesome, if you ask me!