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King Alfred Cakes (Daldinia Concentrica)

King Alfred Cakes / All Year Round / Inedible

Scientific Name

Daldinia Concentrica

Common Names

King Alfred Cakes, Coal Fungus, Carbon Fungus, Cramp Balls




They are saprotrophic and can be found in groups on dead or decaying hardwoods, most often on ash and beech.


An easy to identify mushroom, they are very common in the UK, although not edible they make excellent firelighters and would have been an important resource for our ancestors.

Identifying Features:


No cap as such, the round or spherical fruiting bodies called stroma have no gills, pores etc. they are also without a stem. The common name ‘Coal Fungus’ is very apt.

When young they are purple-brown in colour but soon turn almost jet black.

They can remain on the tree for many years, each year produce a new layer of growth so that their age can be read like the growth rings on trees. I.e. the bigger the fruiting body the older the fungus.

When they are cut in half you can see these growth rings appearing as concentric circles of black and silver.

J Milburn, CC BY-SA 3.0 <>, via Wikimedia Commons
Björn S…, CC BY-SA 2.0 <>, via Wikimedia Commons


No real smell.




When dried they will take a spark from a flint and steel, so they are a really useful bushcraft tool.

Our ancestors would have used them to transport fires, as they will smoulder for hours once lit. There can also be used a bit like a charcoal briquette and apparently, they are taught to the special forces as they don’t produce smoke so help them to remain undetected.


The younger brown bodies are not really useful, you want large, black examples which are lighter and more brittle and they need to be completely dried out before using them for fire lighting. They can live on the host year for many years but grow between spring and autumn.

Also, they will produce their spores for a long time after they’ve been picked and leave a ‘sooty’ mark so be careful where you store them.

Dendrofil, CC BY-SA 3.0 <>, via Wikimedia Commons

Potential lookalikes

There are a few similar black, crusty fungus’ growing on dead wood. The Brittle Cinder Fungus (Kretzschmaria Deusta) does not form ball-shaped fruit bodies and when cut in half doesn’t have the concentric pattern of rings.

Extra Notes

The common name King Alfred Cakes is said to come from the time when King Alfred was hiding from the Danes, he was given shelter by a woman and he promised to keep an eye on her cakes in return He forgot all about the cake and they burned. It is said he then scattered them throughout the forest to hide his mistake!

The name Cramp Ball comes from the belief that carrying them in your pockets relieves cramp.

I’ve used the spores from this mushroom for making incredibly fine black ink in the past, the micron size of the spores is absolutely tiny and therefore produces an incredibly fine and easy to use black ink. To Collect the spores I picked them before sporulating, laid them on paper until they sporulated and dropped their spores on the paper. I then mixed these spores with water and gum arabic (the gum from a cherry tree would work too) to create the ink 🙂

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