Not for your toast – Witches’ Butter

After a pretty unsuccessful local walk looking for the more favourable spring mushrooms I happened to stumble across these ugly little beauties! Any ‘find’ is a bonus anyway, and I was also glad to get some good shots of them too…

It’s common English name is Witches’ Butter (Exidia glandulosa) and is a widespread, common jelly fungus found throughout the year. It is found on dead wood of deciduous trees, usually on fallen branches but also on dead standing wood too.

At first glance, groups of this black jelly fruiting bodies look like scattered blobs of tar on the dead branches and it’s only on closer inspection you notice the finer details.

Exidia glandulosaGenerally 2-4cm in size, they can grow up to 6cm in diametre and are attached to the wood by a very tiny stem that is only noticeable once you have removed them out of situ.

They are often misshapen but usually disc shaped with randomly scattered tiny warts on their smooth, almost felt-like surface. Fruiting bodies often merge together and overlap giving the deceptive appearance of being one big fused mass of black fungi.

The consistency, as you’d expect, is very ‘squishy’ and gelatinous. Soon after wet weather they are more conspicuous and at their most productive. In prolonged, dryer weather they can shrivel up to hard membranous lumps. But fortunately for them, can rehydrate very quickly and hence last all year round.

Other similar looking fungi include Exidia plana, also known as Black Witches’ Butter (which is a confusingly similar English name!) and is made up of many smaller cup shaped fruiting bodies, merging together to give it a ‘brain like’ appearance, and Black Bulgar (Bulgaria inquinans) which lack the small pimples are shaped like a disc when mature. All very weird indeed, and needless to say, these (like our common Witches’ Butter) are also inedible.

Witches Butter fungus Identification

Top: Typical disc shaped Witches’ Butter on a fallen branch and the brown jelly flesh inside. Below: Several fruiting bodies on the same branch, with several fusing together.

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