A roadside beech colonised by Ganoderma resinaceum

Here’s a nice one! As I was out surveying, there sat this large roadside beech (Fagus sylvatica) that sported a trio of sporophores of the lacquered bracket (Ganoderma resinaceum). Curiously, this association between host tree and parasitic fungus is a not-so-common one in the present day, in comparison to this fungus upon oak (Quercus robur) – in spite of the lacquered bracket historically being more common on beech than any other tree.

Evidently, judging by the past prunung cuts, an arboriculturist made the decision to manage this beech. Whether or not it was due to the presence of this fungus is something open to speculation, though there’s certainly reason to prune this beech once more for good arboricultural reasons associated with hazard management – notably because of the busy road directly adjacent to the beech. A PiCUS test might be the best investigative route of action here, though that decision remains with the landowner.

I’m sure that you’ll be able to appreciate the issue to do with hazard management, from the pictures below!

To give a sense of context, this is the position of the beech relative to the adjacent road.

Some rather nice bulging on the main stem, though around the prominent buttress roots we can spot a few sporophores of Ganoderma resinaceum.

Another fruiting body hides on the other side of the buttress!

From the damaged bracket atop the one on the right, either we have prior years of fruiting or this bracket was torn off and another one grew in its place earlier during this growing season.

We can observe how this significant buttress root has likely been produced in response to the white rot associated with the decay incuded by Ganoderma resinaceum.

And a final picture for good measure!

Rigidoporus ulmarius acting as a saprotroph

The distinction between a fungal necrotroph (i.e. parasite) and saprotroph is – in the most basic of senses – easy. The former causes the host woody cells to die as the mycelial network metabolises, whereas the latter metabolises woody tissue that has already died / ceased to serve a vascular function. Indeed, this poses an interesting question, by where many fungi on living trees aren’t actually necrotrophs in the truest sense of the word, as they metabolise heartwood that doesn’t serve a function beyond adding structural support to the overall above-ground structure. Consequently, many wood-decay fungi that degrade heartwood, such as Fistulina hepatica, Laetiporus sulphureus and Phaeolus schweinitzii are arguably saprotrophic – even when found on living trees.

Regardless of that entire aspect of fungal ecology (that’s an entire week’s worth of blog posts right there!), the purpose of this post is to share two finds of Rigidoporus ulmarius (the ‘giant elm bracket’) from yesterday. Both were colonising horse chestnut (Aesculus hippocastanum), and specifically dead specimens. For me, it’s an interesting case, as I generally observe this fungus upon living trees, and despite things I have read this is – from recollection – the first time I have seen this fungus on a dead host.

Without further blabbering, I share below the two specimens, which were within 15m of one another. The other horse chestnuts very close by don’t sport outward signs of this fungus, though the localised and elevated inoculum base has probably resulted in all the horse chestnuts acting as hosts for Rigidoporus ulmarius – to varying degrees.

Peering inside a failed beech bole

The New Forest has no shortage of failed beech, given the fact that most of the beech are mature or veteran in age. Typically, the species of Ganoderma can be found to be devouring the remaining stumps and stems, though sometimes further fungi pop up in the most unexpected of places. In this case, looking inside the significantly-hollowed bole yielded a sight of various sporophores of the fungus Phlebia tremellosa (known commonly as ‘jelly skin’).

Because this species is considered to be generally be saprotrophic, the extensive decay (which appears to be caused principally by a white rot) wasn’t created by this fungus and was likely generated instead by Ganoderma australe and / or Ganoderma resinaceum. However, upon windthrow of the bole, or perhaps even before that time, spores of this fungus germinated upon the wood substrate and have since produced fruiting bodies. Such structures are also kept snugly within a consistently warmer and more humid microclimate, which has probably ensured they have endured the frosts that covered the outside world in the prior weeks.

Roadside Pseudoinonotus dryadeus in abundance

This is only a short post to close-off the weekend, though ideally one that is appreciated – notably, because it showcases the fungus Pseudoinonotus dryadeus in its senescent state and the associated pronounced buttressing employed by the host oak (Quercus robur). I don’t know exactly where this was, though it somewhere along the A371 in one of the villages between the border of Dorset and Somerset through to Cheddar (as if that narrows it down!).

A sublime crown reduction, no doubt!

Perhaps this has something to do with it – what came first, the topping or the fruiting bodies? Given the lean on the oak, I admit I don’t actually know. Maybe the pruning wound low down on the right saw a large chunk of the crown removed, enabling for the entrance of fungal propagules and leaving the tree so one-sided?

Conks of Pseudoinonotus dryadeus litter the central region between two very significant buttress roots, though we can see how the decay extends beyond the strict basal zone. The fibre buckling discernible in the above picture around the location of the fruiting bodies indicates reaction growth, in response to said buckling under the white rot conditions occurring within.

Tearing off a small fragment of one of the old fruiting bodies, we can see how spiders have used the bracket as a nesting site (assuming the white mass is a spider’s abode for eggs, which I have seen similarly in spent conks of Ganoderma spp.).

Fungi everywhere on a single declining beech pollard, New Forest (UK)

I was forunate to be able to spend some time in the New Forest yesterday, having driven back from Somerset after picking up a microscope (more on that, in due time). When last down there, which was during mid-summer, I spent a few hours sojourning around the Bolderwood / Knightwood Oak ornamental drive, with specific focus upon the myriad of mature and veteran beech pollards that dressed the roadside. One beech, even then, alluded to fungal parasitism, given its dire vigour and evident crown retrenchment (perhaps associated with ground compaction, given its close proximity to a car park and the Knightwood Oak). Therefore, I paid a visit to this beech, with the hope of finding some fungi – and I wasn’t disappointed!

I’ll actually be honest and say this beech is testament to the ability for the species to provide for many wood-decay fungal species. I really don’t think I have ever seen a tree more covered in fruiting bodies of many species than this one, and we’ll run through the suspected species below. First, we’ll look at the tree as a whole, however, and from the first image I don’t think there’s any debate over its poor condition. Granted, with the impending demise of a tree, weak fungal parasites and saprotrophs can enter, and this alludes to the cyclical aspect of energy transfer. In time, this beech will be the food for other plants and trees, though for now it’s fungal food.

I wonder how many more years this beech has before its snatched from the throes of life! Probably not many.

The arrows relate to the various fungal species found. Working clockwise from the tip of the centre, I spotted what I suspect are Hohenbuehelia atrocoerulia, Chondrostereum purpureum, Mensularia nodulosa (confirmed), Exidia plana and Bjerkandera adusta.

Here, behind a limb adorned brilliantly with one of the ex-Inonotus species, sit some fresh oysters (Hohenbuehelia atrocoerulea). Evidently, they are free from frost damage, suggesting they are probably only a few days old.

There’s also a younger set emerging just behind this cluster in the foreground!

Looking down the main stem, here we can observe how Chondrostereum purpureum and Mensularia nodulosa are inter-mingling. On the whole, it appears the Chondrostereum is more limited in its amassed substrate, if the presence of fruiting bodies are anything to go by – the ex-Inonotus species is abundant on the trunk and further up into some of the limbs.

In this image we can identify how the two species really do run right up to their respective thresholds.

For good measure, these are older sporophores of Chondrostereum purpureum. In their juvenile days, they’d have been far more attractive.

Further round the trunk, we enter the sole territory of the Mensularia nodulosa.

Angling upwards, the slotted nature of the tube layers becomes very evident.

Down on one of the buttresses, this witches’ butter (Exidia plana) gets comfy amongst mosses. Note that it’s more likely to be this species of Exidia, as Exidia glandulosa is more often found on oak. To discern between the two however, you’d need to inspect some spores under the microscope.

Looking more closely one can appreciate (I guess…?) why it’s called witches’ butter.

And up on another limb, we have what is probably Bjerkandera adusta.

It seems to be ejoying the decay column from the pruning wound and general dysfunction.

There’s also some gilled sporophores in this one, which could potentially be Panellus stipticus, though they were too sparse and too small to see properly.

A wintry visit to Greenwich Park, London

Yesterday, as part of our monthly aim of visiting sites across the south east of England, a half-dozen strong group of arboriculturalists made the journey to London’s Greenwich Park – myself included. Indeed, as much of the park consists of deciduous specimens (principally, avenues of Castanea sativa and Aesculus hippocastanum), the park was rather bare in the foliage sense, though such barren canopies did allow us to appreciate the true magnitude of – most notably – some of the veteran sweet chestnuts. The frost-clad ground and crystalline sky provided a similar beauty, and thus we shall begin with one of the most iconic vistas from Greenwich Park – the city skyline.

As we stood adjacent to the observatory, we could admire – amongst the furor of tourists and scout groups – the sightly perverse beauty of a city. I say perverse, as such artificial and polluted landscapes don’t tend to suit those who don’t consider themselves urbanites, which includes myself.

Of course, we didn’t go there for the view, so let’s get into the main bulk of this account – trees and fungi. There’s no real order to how the below series of images rank, so don’t consider this post a chronological reflection of our trip!

Perhaps the best place in which to start the core section of this post are the huge sweet chestnuts, though we must begin on a rather sombre note. With a species of Phytophthora suspected on site and some of the older individuals exhibiting stunted and chlorotic leaf growth, there is a valid concern for the future of these veterans which is – without doubt – highly concerning. During the winter months, fully appreciating this contemporary issue is difficult, though we did spot some foliage on the floor that was certainly smaller in size than would be typically expected. Alas, this situation should not impact adversely on our admiration of these trees, and should in fact raise attention and draw intrigue to those within the industry and beyond, with an eye to ensuring we continue to care for the current and future populations of veterans. Therefore, promoting the Ancient Tree Forum and their most recent publication on ancient and veteran tree management is critical. And now, for some fine shots of various veterans!

This veteran sweet chestnut was the first one to greet us as we entered the park from the southern end. Not a bad induction!

As the city blocks paint the skyline to the right, we get a brilliant juxtaposition between the historic and the contemporary. In such a dynamic and ever-changing landscape such as London, this veteran sweet chestnut acts as a vestige of the old.

From another angle, the same sweet chestnut as above’s form can be more greatly appreciated. The helical patterns of the wood fibres and bark are as if they have been wound like rope.

This veteran has seen better days, though still stands proudly by the cafeteria. The ground beneath is woefully compacted, which must be having an impact upn the tree’s ability to function as a living being. Unlike the two shown above, it also doesn’t have a layer of mulch applied around its rooting environment.

Some of the veteran sweet chestnut we came across were also home to two annual common wood-decay fungi – Fistulina hepatica and Laetiporus sulphureus. Without doubt, the state of the fruiting bodies was not good, though when ravaged by time, wind, rain, frost and sun, to still even have a form is respectable! Certainly, a summer visit would have yielded a much greater haul of these two fungi on the sweet chestnuts, so a summer visit is probably on the cards.

One of Greenwich Park’s many veteran sweet chestnuts with an added extra – a small and rather weathered…

…you can see it…

…Fistulina hepatica! Picked off by parasitism before it reached a respectable stature, it still nonetheless produced a hymenium and thus likely produced spore.

A second sweet chestnut, this time slightly smaller, but again with Fistulina hepatica.

The state of it is, however, diabolical!

A smaller and thus younger sweet chestnut, in this instance.

It sports a fungal fruiting body, nonetheless!

A chicken of the woods, which is beaten and bruised.

Another smaller sweet chestnut, and another Laetiporus sulphureus.

Note how it emerges from behind a bark-covered area.

Again this sporophore is long beyond its best, though retains a little more dignity in the face of its impending crumble.

Away from the sweet chestnut, there was a variety of other large trees. Below, I share the ones that were home to fungi, through the identification of fruiting bodies. Absolutely, all trees on site are host to many species of fungi, though fruiting is not necessary in many instances, and it certainly costs the fungus energy to create and sustain. To begin, we’ll take a look at the ever-accomodating mature Robinia pseudoacacia in the park, which didn’t disappoint. In all, the population supported three species of wood-decay polypore, as we will see in the below images.

A very mature false acacia, with a very mature Laetiporus sulphureus fan on the main stem.

Well, sort of a fan – the remains of!

I imagine someone yanked this off, as it looks like a rather clean break.

Very close by, a second false acacia cradles another Laetiporus sulphureus.

Here, we can see how it’s at the base of the main stem, in place of higher up the structure.

This second one is far worse for wear!

A double-stemmed Robinia pseudoacacia, which was once at least triple-stemmed.

At the base, a senescent Perenniporia fraxinea and a cluster of broken active sporophores can be seen.

For good measure,here’s a better look at the entire bunch.

It’s a little disappointing that the fruiting bodies have been damaged, though that doesn’t stop them being Perenniporia fraxinea!

And a second example of Perenniporia fraxinea on this false acacia, too.

Right at the base, to the left.

This one appears slightly different to how it’d usually look (it’s not photogenic!).

Regardless, a showing of the trama reveals it as Perenniporia fraxinea.

It looks like the park managers are aware of the decay on this Robinia, as it has already been pruned!

If you look between the buttresses and into the basal cavity, you can spot a single Ganoderma australe. More were on the other side of the tree, though were old and worn.

With the sun behind the camera, this southern bracket looks rather pretty.

Steering attention away from false acacias, I now turn towards a focus on the brown-rotting polypore Rigidoporus ulmarius. With both horse chestnut (Aesculus hippocastanum) and beech (Fagus sylvatica) on the site, the chances are that there would have been a few examples of this fungus. Indeed, there were, as we will observe.

This first example, on horse chestnut, is an interesting one.

It’s the return of the cavity-dwelling Rigidoporus!

Away from the wrath of the elements, this sporophore doesn’t have the algal green stain atop and bathes in its own substrate.

A cutting identifies this specimen as Rigidoporus ulmarius, with the cinnamon tube layer and brilliantly white flesh.

The second horse chestnut sits in line for the toilets, patiently waiting for soneone to give it the 20p needed to get beyond the toll gate.

If you want, you can even sit down to inspect this tree!

This might well be this sporophore’s first season. I wonder how many more years it will see before it gets knocked-off or is aborted.

Half way up this steep hill, a beech stands seemingly without significant issue.

Oh, wait – here’s the issue!

Is that a shade of green?

From this shot, it looks most probably like Rigidoporus ulmarius. If so, we have two examples in one site of its cavity-dwelling abilities!

Greenwich Park also has a good number of large plane trees (Platanus x hispanica). The most abundant fungus on these trees was massaria (Splanchnonema platani), and there probably wasn’t a plane in the park that didn’t show at least some signs of its presence. However, it was the large plane with Inonotus hispidus that gained much of my eager attention, given I am not often around mature planes with extensive fungal decay.

A rather lofty plane tree.

As the crown breaks, we can spot a single Inonotus hispidus sporophore.

Whether there is an old wound at or around this site is hard to say, though for this fungus to be able to colonise one would expect so.

Perhaps an old branch stub above the fruiting body?

To round this post off, which has admittedly taken a long time to write, I’ll share some lovely images of a not-so-lovely bird – the parakeet (Psittacula krameri). Plaguing many of London’s parks and beyond, these things produce an utter cacophony and are certainly invasive, though one must admit that they are incredibly photogenic. Below, I share a few examples of where the parakeets were using cavities for shelter.

A horse chestnut monolith, seemingly vacant.

Wrong! Enter the parakeet(s).

This one stands proudly atop a pruning cut.

Along a plane tree branch, this parakeet appears to be guarding its abode.

“Oi m8, w0t u lookin’ @???”

Winter wood-decay fungi

The weather has been quite superb over the past few days, and I utilised my lunch break today to get out and explore a country park I visit probably once every month or two. Unfortunately, it’s pretty massive, so covering the entire place takes far longer than a single hour, though that doesn’t dissuade as there are still fungi to find – and fungi I did find.

The title of this post, I’ll admit, is a little devious. Yes, it’s winter, and yes, these are fungi, though some are perennial polypores that essentialy cheat the system a little. Worry not, however, for there are a few examples of annual fungi thrown in for good measure. Regardless, the mix found today was pretty decent, and a few of those species shown below aren’t ones I come across very often.

We’ll begin with Perenniporia fraxinea, which I found on two different ash within very close proximity to one another. The second example is easily the best, as some of the brackets were absolute monsters (though it was the smaller ones that drew my attention to them). Sadly, due to the strong sun and the sheer mass of bramble and bracken surrounding the ash, getting good photos was incredibly tough, though the ones beneath are suitable enough to offer a sound appreciation of their size. If you look hard enough, you’ll undoubtedly find similar-sized examples, as they aren’t too difficult to track down if you know where there are plenty of large and mature ash. The first example is still useful, however – it demonstrates how variable the morpohology of the species can be.

Interestingly, the first example of the above Perenniporia fraxinea yielded another treat – Coriolopsis gallica, atop. From what I have seen of this fungus, it tends to favour ash (Fraxinus excelsior), though as it isn’t one I see that often it might simply be a bias from my observations – ash are, around here, abundant, and there is no shortage of wind-damaged ash and fallen limbs adorned with fungi. Relatively nearby, another ash, in the form of a fallen limb, supported a separate colony (or colonies) of this species, and both examples are thus shown below.

Essentially adjacent to the second example of Coriolopsis gallica stood a large hornbeam (Carpinus betulus), which had a longitudinal section of cambial dieback tracking its main stem from the death of the branch above. Despite not being at all uncommon, along this area of dieback were multiple sporophores of the fungus Ganoderma australe.

And finally, right at the top of another ash (which also was dressed with Inonotus hispidus) sat what appeared to be Pleurotus ostreatus – albeit, very mature. Exhausting my camera’s zoom lens, the below photos were captured. Given the position, size and colour of the fruiting bodies, I doubt it could be anything else.

Tell a lie, there’s actually one more series of shots to show. This time, we have an oak (Quercus robur) that has fallen and since reiterated to form a new crown, courtesy of phototropism. At the cusp of the transition between functional and dysfunctional wood stood this rather tiny little sporophore, blue in colour. From my experience and knowledge, I would suggest that this is Postia subcaesia, which is a species of the genus Postia that is routinely found on deciduous trees – most species are largely found on gymnosperms, however.

Urban fungi – streets and parks

It’s somewhat overcast at the moment and it’s rather cold outside, though that doesn’t mean the world grinds to a halt. Indeed, fingers might move a little more slowly and words might be slurred as the wind howls and the frost lingers, but one can retain enough sensibility to grab a camera and get out to look at trees and fungi. Perhaps this is when the urban heat island effect is appreciated a little, in fact – urban parks aren’t as cold as the open countryside! There’s probably a joke in there somewhere…

Poor jokes aside, my morning sojourn around an urban park and the adjacent streets was rather fruitful, in terms of fungi that could be found. Admittedly, as winter builds its temporary bulwark everything runs for shelter – fungi are often no different in this regard, with mycelium remaining cosily within its sheltered substrate. Sometimes, and notably for polypores, the weathered remains of old fruiting bodies signals the presence of colonisation, and thus many of the below finds detail this. Of course, one must still be able to identify the remains of fruiting bodies where they exist with some dignity, and therefore a mid-winter exploration can in fact yield very constructive results. For me, the diversity of finds in this state was quite pleasing, considering I spent perhaps two and a half hours essentially walking in circles. Granted, some fungi are true hivernophiles, so look out for fresh fruiting bodies, too!

My morning walk first took me to an oak I actually drove past two days prior, though unfortunately at the time I couldn’t stop. Thus, I detoured via this park first of all, and snapped a few (heh, a dozen…or two) photos of a senescent Laetiporus sulphureus with a great view of passing traffic.

In this dire light, this huge oak is almost a silhouette in the landscape.

Notice two historic pruning wounds where old poles (this is almost certainly an old pollard) were removed to allow for safe passage of vehicles.

The pruning wound on the right sees a single fan of Laetiporus sulphureus sit boldly over the road. Didn’t it ever get told not to play with traffic?

Detour over, I made my way to the main site for my morning’s walk. The first tree (or monolith) I came across, which was a horse chestnut (Aesculus hippocastanum), shown earlier in the year in this blog post, I inspected once again. With much of the dryad saddle (Cerioporus squamosus syn. Polyporus squamosus – it had its name changed recently) now senescent and dressing the floor beneath, my focus was turned to the now much larger southern brackets (Ganoderma australe) and the myriad of silverleaf (Chondrostereum purpureum) sporophores that adorned the trunk. The latter were of interest to other park users, who were taken aback by the wonderful colourations of this species. In one of the below images, you’ll even be able to see its cerebral-like morphology.

Fungi everywhere. Literally.

You can see three species in this photo: Cerioporus squamosus (on the floor), Ganoderma australe (middle) and Chondrostereum purpureum (right).

Here’s the nicest sporophore of Ganoderma australe. It’s such a variable bracket in terms of its shape and colour, and this study alludes as to reasons why.

Some Chondrostereum purpureum that has both fresher and more mature (yellowed) sporophores.

It really does look like a brain, no?!

From here, I turned my attention to a few nearby trees. One hacked-at purple plum (Prunus cerasifera ‘Pissardii’) was littered with Ganoderma australe and cushion bracket (Phellinus pomaceus) sporophores, though I admit I was more interested in the high-up Laetiporus sulphureus on a lofty black locust (Robinia pseudoacacia). This is an association that is rather frequent, and given the higher parenchyma cell content of black locust, is perhaps less immediately serious when compared to the fungus’ colonisation of willow (Salix alba, notably).

The red arrow marks the spot!

Granted, this isn’t anything morphologically fantastic, though the longitudinal wound above to the right (complete with a woodpekcer hole just out of shot) probably is associated with the presence of Laetiporus sulphureus.

Zooming in 60x, this is the slightly blurred result. We can see the sporophores tucked neatly within the ever-common fluting present on mature black locusts.

Not too distant from this false acacia stood this ash monolith (this park is full of them, which is great), complete with four sporophores of Perenniporia fraxinea at and slightly distant from the butt. As you’ll recall from my recent post on the hosts of Perenniporia fraxinea, it actually has quite a broad host range (add hornbeam to this mix, too), though ash is arguably its most frequent host. The examples here aren’t too brilliant, though the one on a main anchorage root provides us with a curious example of why we should not just look at the stem base of the tree for this species.

Fraxinus ex-excelsior…!

Spot the three Perenniporia fraxinea at the butt and one just behind on a principal root (look to the top right).

This angle is probably slightly better for spotting the one out on the root, though in front of that is this rather flashy example of Perenniporia fraxinea in its less beautiful state.

If you still felt you had to re-position the Hubble Telescope to see the one out on the root, worry not – here it is!

Not wanting to now litter this blog post with countless examples of Inonotus hispidus on ash, I’ll instead take you to a close relative of this species: Inonotus cuticularis. Most often found on beech (Fagus sylvatica), though sometimes also oak, it operates in a similar fashion to its relative on ash and is therefore found most routinely on or around branch and stem wounds. Here the beech was directly roadside (and just outside the park), and the wound the sporophores were seen on probably arose from a branch removed during road construction / management.

A busy arterial road might separate us, but that doesn’t mean you can’t be spotted…

…for repositioning the Hubble granted us this image of Inonotus cuticularis!

And this one too, actually. Certainly far more interesting than the nebulous notion of there being countless star systems littered across an endless spatiotemporal vacuum…?!

Funnily enough, this beech stood almost opposite a silver maple (Acer saccharinum) – again roadside – that sported a few sporophores of Ganoderma australe. The future of this silver maple is potentially questionable, at least in its current un-pruned state, given the aggressive pathogenicity of this fungus.

Not the largest silver maple, though its position certainly would prompt a discussion of its future management needs.

It appears that there could be the beginning of what is considered ‘bottle butt’, which would be facilitated by the selective delignification of Ganoderma australe.

It looks as if something caused the upper tier to break in the recent past (last few years), as new growth has been initiated beneath and thus a new bracket is forming.

Getting back into the park, there are a few fingal finds that are interesting enough to be shared. The first we have already seen on this virtual fungal tour, though this time it was colonising a poplar (Populus sp.) and was still attached to the tree. Yes, I’m harping on about Cerioporus squamosus! Up high on an old pruning wound sat a small duo of sporophores, senescent and probably sun-, frost- and wind-scorched!

I’m being kind once again – the arrows guides the way!

There’s some serious dieback around these old pruning cuts, in fact. Plenty of barkless area can be seen, and thus at least decay within these (hopefully effectively compartmentalised) regions of wood.

The 60x zoom coming in handy again for this shot of Cerioporus squamosus!

To round off, there was also another monolith (!!), and once more provided courtesy of a horse chestnut, acting as a host to two species of fungus: Ganoderma australe and the giant polypore (Meripilus giganteus). The southern brackets, by virtue of their perennial nature, endure winter quite effectively. The giant polypore, on the other hand, does not. Nor, probably, does it appreciate dogs tearing it apart and urinating upon it! Regardless, the sight of a wrangled and devastated Meripilus giganteus is a rather common one at this time of year, and for all you fungal sadists out there this is for you!

If you hadn’t already noticed (the eagle-eyed lot that you are), there is a tuft of grass growing out from the top of this monolith.

A water-soaked, blackened, deflated, slightly rotten Meripilus giganteus.

This one is, too!

At least this little Meripilus giganteus retained some form of dignity, staying somewhat upright and dry.

Meripilus giganteus finds from the field

For those of us in the arboricultural world, we are certainly aware of this wood-decay fungus. Its presence is often much maligned and associated with significant risk, and indeed in many an instance such concern is warranted. However, it can also act saprotrophically, decaying abscised or dead roots that provide no structural support. Therefore, caution is always to be exercised when making conclusions about trees with Meripilus giganteus, and Julian Forbes-Laird provides a good little write up on his views of the fungus here.

The purpose of this blog post is not, however, to pull apart the literature and assess what level of risk this fungus presents us with. Instead, I am here to show you a bunch of pretty awesome images, showing the host range I have personally seen Meripilus giganteus possess. Indeed, there are hosts not listed here that it is indeed found upon, though on a personal level seeing something first hand is much better than reading about it in a book and never actually getting to see what it is you have read. Get out and explore!

Acer pseudoplatanus (sycamore)

The only time I have seen this fungus on sycamore is on a stump – oh, how interesting…! To be perfectly honest, seeing it on a living host is far more exciting, though this does a good job of illustrating its ability as a saprotroph. Furthermore, it’s actually not at all bad as an example, and some oyster mushrooms even snuck in on the party – as did honey fungus on the root plate.

Acer saccharinum (silver maple)

Again, this is an association I have observed only once. For the number of silver maple about and the fact that many of them are maturity, I’d expect for this association to increase in local abundance in the coming decade or two, though for now one single example suffices to prove the point – this association does happen! Unlike on the sycamore stump, it’s a single mass of fronds and has indeed peaked and is now therefore senescent. A shame I didn’t catch it a week or so before, but oh well – we need to be able to identify fungi in all their stages of life, when out assessing trees.

Aesculus hippocastanum (horse chestnut)

Let’s be frank here – what doesn’t attack this poor species?! It is riddled with everything under the sun (I am surprised it hasn’t been attacked by ash dieback and Dutch elm disease…), and it being a suitable host for Meripilus giganteus is no different. The images below are from two separate trees, with one showing the near-primordial stage of fruit body formation, and the other demonstrating how bleedin’ sneaky this fungus can be. A master of subterfuge!

Carpinus betulus (hornbeam)

This is another association I have come across only once, and this hornbeam (which has seen far better days) happened to be laden with Ganoderma australe as well. Again, this one was caught a little late, though it once more outlines that Meripilus giganteus can surprise us with what it uses as a host.

Fagus sylvatica (beech)

Yes, I have seen this association more than once – easily! It’s arguably fair to say that this is the most widely-known host for Meripilus giganteus, in the UK. Below are a selection of photos that show the better examples I have come across.

Quercus robur (English oak)

This association is one I see a fair bit – not at all as abundant as it is found with beech, however. Typically, the oaks are at least mature and crown condition isn’t fantastic, though that’s nothing compared to the one I found on red oak below!

Quercus rubra (red oak)

For this one, I am just going to let the pictures do the talking. As far as I am aware, this oak is being removed, and rightly so!

Sorbus aria (whitebeam)

Now this last one I wasn’t expecting! It’s very beaten and bruised and has succumbed to the elements a fair bit, but it is the only time I have ever seen this association and might well be the only time I ever do. The whitebeam is certainly mature, and the entire line are afflicted with one thing or another – this one has Meripilus giganteus, the next one has Ganoderma australe at the base, and another has its dead roots being colonised by Abortiporus biennis. The sorbi taking one for the fungal team here, evidently!

Cool fungal finds in the urban streets

Winter is getting on but fungi are still doing their thing, and below are two of the better ones I found this last week. The chances are that those of you reading this have seen these two fungi before, though what is curious about the below tree-fungi relationships is either the spectacular arrangement of the fungi on the host or the unusual host species.

Abortiporus biennis (blushing rosette) on Sorbus intermedia (Swedish whitebeam)

This association is posted as it’s just a really great example of what this fungus can achieve – with regards to sporophore (notably as a teleomorph, where a hymenium is present and there is sexual reproduction) production – with the right conditions. The poor Swedish whitebeam certainly has seen better days, and has evidently died either nearly or entirely. Thus, the mycelium of the blushing rosette is having a field day, and is devouring the principal roots, as we can clearly see from the below images.

Many sporophores of Abortiporus biennis encircle the stem, sitting at around 20-60cm out from the fulcrum.

And now we begin to circle the stem…

This one is certainly mature!

And this one is an anamorphic mess!

These are some of the teleomorphic sporophores, and thus produce spore via basidia.

And this one is the most photogenic of them all. It has awarded itself with a rosette and blushed accordingly. Yeah, bad joke…!

Ganoderma resinaceum on Crataegus persimilis ‘Prunifolia’

The lacquered bracket is supposedly rare, in the UK – nationwide, perhaps. However, in the south east of England, it’s actually rather frequent, and is usually found on oak and less so beech. However, there do spring up a few more obscure hosts, and beyond seeing it on willow and poplar, I have now also seen it on the broadleaved cockspur thorn. A search of records indicates no prior record of this association between fungus and tree, and therefore perhaps this is the first time it has been observed. Honestly, I doubt it, as people see things everyday and don’t inform the correct fungal authorities (namely Kew Gardens, for the Fungal Records Database), though it is nonetheless a really awesome find and it did make my afternoon!

Even the sun is illuminating this thorn!

Huzzah! Relative fungal devastation going on down there – plenty of brackets, and thus plenty of white rot. Not a good day to be a broadleaved cockspur thorn.

A little closer and we can see the lacquered upper surface being obscured slightly by the brown spore released by Ganoderma resinaceum.

And closer yet again, solely for good effect.

And a cross-section. Cutting into the brackets of Ganoderma resinaceum is not that easy, as they have quite a rubbery resistance to them. Use a very sharp blade for a clean cut!