Rigidoporus ulmarius on Populus x canadensis (hybrid black poplar)

I had a little bit of ‘spare’ time this morning, so went to look at a line of poplars that I have passed many times before. There’s a really good Prunus spinosa nearby that is absolutely laden with Phellinus pomaceus, and therefore I thought I’d try my luck and see whether any of the poplars were showing signs of fungal decay. I was principally looking for Rigidoporus ulmarius, as I have seen it colonising poplar before, and thus, because these poplars are of decent size and age, there was at least some chance of one of the good dozen sporting a sporophore. Thankfully, and I am not kidding when I say this, the last poplar I looked at had one at its base, and if I hadn’t bothered to turn my head to look through some of the undergrowth I wouldn’t have seen it.

Below, I have attached some images that hopefully set the scene and give a good indication of what Rigidoporus ulmarius looks like, though of course my other posts of this fungus (obtainable via the sidebar under ‘Categories’) also help to demonstrate its host range and general morphology.

Here we see the poplar in its entirety. As can be easily observed, there is a footpath just alongside.

After cutting through some of the undergrowth with a pair of secateurs, I was able to get closer to the fungus. In this shot, we can see how the sporophore sits in comparison to the butt. For a sense of scale, this sporophore was around 15cm in width.

Alongside the sporophore, numerous exit holes of the hornet clearwing (Sesia apiformis) can be seen. Perhaps the fungus entered via such means?

Just another shot of the sporophore. Nothing much else to say on this, though do note the algal greening atop, as this is a characteristic of this fungus!

More of a side-on profile in this image, where we can see the orange tinge to the pore surface.

A closer inspection of the underside.

Cutting the bracket open to take a cross-section, we can ascertain that this is most probably Rigidoporus ulmarius, because of the orange-brown tube layer and brightly white flesh.

Advertisement