The last few days have seen a sudden change from a very warm and sunny late summer to a much cooler and rather rainy start to autumn. Flowers and insects are on the wane but fungi are starting to appear.

I was cycling near Carleton Rode, south-west of Norwich, a couple of weeks ago and passed an oak tree by the roadside with some distinctive bracket fungi growing at its base and stopped to take a look.

They were the Oak Bracket, Pseudoinonotus dryadeus. 

Base of English Oak tree with Oak Brackets, Pseudoinonotus dryadeus

Oak Bracket, Pseudoinonotus dryadeus

In its prime, the Oak Bracket is extremely beautiful. Its velvety upper surface is cream to rusty brown with a yellower margin and is pitted with tubes. These ooze an orange-brown liquid that looks like runny honey, though, as the First Nature website points out, “it is not as tasty as honey”. The fungus is not edible – it is described as bitter and tough.

Oak Bracket, Pseudoinonotus dryadeus, oozing nicely.

The Oak Bracket is a parasite, mainly on species of oak, although Beech, Birch and Alder and Maple, Elm and Sweet Chestnut are occasional hosts. The fungus causes a white rot in base of the trunk (“butt rot”) and eventually branches can die off and the weakened base of the tree can make it prone to toppling. Spores enter through wounds in the tree’s bark so this is “one of many reasons not to damage tree bases with lawn mowers or other equipment“.

The Oak Bracket grows as an annual bracket without a stem. The ones I saw were in their prime; older specimens become corky and fibrous. The caps become blackened and cracked over winter, and sometimes persist for several years. They apparently smell very unpleasant. (The ones I found just smelt slightly mushroomy. I must go back and have a sniff when they’re older!) (See April 2022 update below.)

Oak Bracket is also known as Warted Oak Polypore, Weeping Polypore and Weeping Conk. The last two names refer to its habit of oozing liquid, but it’s worth knowing that other species of bracket fungus also weep. Two examples are Shaggy Bracket (Inonotus hispidus) , found especially on Ash and Apple trees, and Alder Bracket (Inonotus radiatus), found on Common Alder.

The Oak Bracket’s original scientific name was Boletus dryadeus and prior to 2001 the accepted name was Inonotus dryadeus, which is still used in some field guides (such as Sterry and Hughes) and on some websites (e.g. Wikipedia, Messiah University).

The First Nature website has some good pictures of the Oak Bracket. It also tells us generic name Pseudoinonotus comes from pseudo (false), ino (fibrous), ot (ear; also used in Otidea bufonia, the Toad’s Ear fungus) and –us (making it a Latinised noun). The specific name dryadeus means ‘found with or on oak trees’.

Pseudoinonotus dryadeus is commonest in the southern half of the British Isles. At the time of writing the NBN Atlas lists 292 records, with just three in Scotland. It also occurs elsewhere in temperate parts of Europe and in North America.

The Oak Bracket shouldn’t be confused with the Oak Polypore (Piptoporous quercinus), which is very rare in the British Isles and grows only on veteran oak trees (though there is apparently one old record on a Beech).

Cross section through a Crunchie bar.

When fresh Pseudoinonotus dryadeus also resembles a section through a Crunchie Bar but the taste, difference in size and presence of a chocolate coating on the latter should avoid confusion.

April 2022 Update

I did go back and sniff the Oak Bracket, in December 2021. The fruitbodies were now greyish black. There was no smell at a distance but if I sniffed the surface I could just detect  a not very pleasant nitrogenous smell of rotting fungus, like a cultivated mushroom that had been sweating in the fridge for too long.

I cycled past again on 10th April 2022 and was shocked and saddened to see that the Oak tree had gone. The gales in late February may have toppled it, or a farmer or tree surgeon may have seen the brackets and decided to remove the tree. There were only some thin twigs left, plus a few shattered remains of very woody (and not at all smelly) Oak Bracket on the ground. I took one home as a souvenir.