Porcelain Fungus, Oudemansiella mucida. Photograph by Vanna Bartlett.

Autumn seemed to arrive suddenly this year. In the last week of September it was still summer, then temperatures became more seasonal and we had some rain at last. With autumn came fungi.

On Monday we walked through the woods at Felbrigg Hall in North Norfolk. This is where I saw my first Porcelain Fungus (Oudemansiella mucida) several years ago. It was high up in a Beech tree but nonetheless the shiny white fruit bodies were unmistakable (see some great photos here). This time, however, we were lucky enough to find the fungus on a Beech stump and we could admire it in all its shining, slimy glory.

Porcelain Fungus can be found throughout northern and central Europe (see UK distribution) and grows on dead or dying Beech trees, or on dying Beech branches. Autumn is the time of year to see it. Sometimes it is very plentiful and the fruit bodies can cover an entire tree.

Porcelain Fungus is very slimy and its specific name, mucida, refers to the layer of transparent mucus that covers the fungus’ cap. The genus Oudemansiella contains between 15 and 42 species, depending on which classification system is used, and is named after the Dutch mycologist Cornelius Anton Jan Abraham Oudemans (1825–1906). Other English names for Porcelain Fungus include Poached Egg Fungus and Slimy Beech Cap.

The fungus is edible, though I haven’t tried it yet. It has the advantage of not looking like anything else, but if you do decide to try it, remove the mucus first. John Wright (in the River Cottage Mushrooms Handbook, which I have recommended before) describes how he was converted to eating this fungus. The mucus should be washed off and tough stems removed and then the caps can be sauteed. Apparently the flavour is “surprisingly rich”. The Wild Food UK website says Porcelain Fungus has a “good mushroomy taste”.

Porcelain Fungus fights off competing fungi by producing fungicides called strobilurins. (The name comes from Strobilurus tenacellus, the Pinecone Cap, which is where the compounds were first isolated. The Pinecone Cap uses strobilurins to stop competing fungi from growing on the pine cones on which it grows.)

According to an article in Pest Management Science entitled ‘The strobilurin fungicides‘ (D. Bartlett et. al 2002), commercially produced strobilurins were first sold in 1996 and sales totalled approximately $620 million in 1999, representing over 10% of the global fungicide market.

In the UK, DEFRA produces a fact sheet on strobilurins, ‘Use of Strobilurin Fungicides on Cereals‘ and The American Phytopathological Society has produced ‘Q_oI (Strobilurin) Fungicides: Benefits and Risks‘ on its website, which explains how the fungicides are applied. Strobilurins work by blocking electron transport in mitochondria so that they can no longer produce energy. Since their introduction in agriculture, some fungi have become resistant to strobilurins, so they are now used more sparingly, often in conjunction with other chemicals. (See also ‘Resistance Management is Essential with Strobilurin Fungicides‘.)