Perenniporia fraxinea not on Fraxinus sp.

It’s fair to say that the epithet fraxinea is not indicative of the quite broad host range of this fungus. Granted, the same can be said about many other fungi, including Rigidoporus ulmarius and Pleurotus dryinus, and perhaps that’s one of the things we have to watch out for when it comes to identfying fungi on trees (and more broadly). Dealing specifically with Perenniporia fraxinea, which probably doesn’t have a common name, I want to share what other hosts I have come across that display signs of colonisation by this fungus (specifically, by identifying the fruiting bodies on the trunk and buttress area). This is, after all, an important aspect of tree management, and pin-pointing where fungi may occur outside of their suggestive range (by virtue of their epithet) is critical as a consequence. The mycological world loves to throw us curve-balls, and therefore we must be able to catch them when they are indeed thrown.

For the sake of ease, I have segmented the below pictures into headings detailing the different host species of Perenniporia fraxinea. I hope that some readers, either now or those who find this via a search engine in the future, find this of use – particularly those in the UK. However, before that, I shall list the host genera Ryvarden & Gilbertson list in their publication European Polypores (note this applies to all across Europe): Aesculus, Castanea,  Celtis, Eucalyptus, Fagus, Fraxinus, Gymnocladus, Juglans, Olea, Malus, Platanus, Populus, Prunus, Robinia, Quercus, Salix, and Ulmus.

Acer pseudoplatanus (sycamore)

Only once have I come across Perenniporia fraxinea on sycamore and that was down in Dorchester, UK.

This sporophore as a bit of a mess, with regards to its morphology. Nonetheless, it had a hymenium, and was thus not an anamorph.

Thankfully, the other side of the same sycamore sported a more typical bracket-shaped specimen. Note the white spore around the bracket.

And a cross-section showing the distinctive context of Perenniporia fraxinea, including the fresh yellowish growth.

Aesculus hippocastanum (horse chestnut)

Again, only once have I observed this association. In this case, the horse chestnut was a monolithed specimen, and the sporophores were on the inside of the tree.

Trying to hide in frass and white-rotted woody material!

A cross-section, once again, reveals this fungus as Perenniporia fraxinea.

Fagus sylvatica (beech)

Three times have I witnessed this association on beech, and this was the most recent and the finest example of the bunch. Some great buttressing, too – as is so frequent on mature beech, which look like they’re essentially being ripped out of the ground in which they sit.

A closer look at this tiered specimen, complete with white spore dressing the buttress root. Upon cutting this one for a cross-section, it exuded a nasty ‘juice’.

Note the context, which is very distinctive of a specimen that has had its most recently growth ‘spurt’ mature – i.e. it lacks the yellow-orange rim.

Populus spp. (poplar)

Both Populus x canadensis and Populus nigra ‘Italica’ are hosts I have seen Perenniporia fraxinea on within the genus Populus. Here, I share the better example of the two from the Lombardy poplar. A cracking buttress root there!

On one side of the base we see this collection, all of which are laying down some very fresh growth.

And on the other side some equally fresh growth spurts are taking place. Very photogenic!

Quercus robur (English oak)

Having shared some other examples of Perenniporia fraxinea on oak, I wanted to share a newer example from last week. Three times I have seen this fungus on oak.

Here we can see it’s certainly a sporophore with many years’ growth. This time around, a small layer underneath has been added.

The white spore is so distinctive here, and the upper surface is covered in algae, etc.

And a shot of the hymenium for good measure.

Robinia pseudoacacia (false acacia / black locust)

Robinia pseudoacacia is the second most common host after ash, in my experience (seen it a total of five times on this species). This is an example from earlier today.

Here we have a sporophore right at the base.

And some further up – albeit, much smaller, in this instance.

A closer inspection of two very good-looking sporophores.

And a closer shot of the one at the base – including the white spore once more.

And finally the context, as is typical of this fungus.