Daldinia concentrica, King Alfred’s Cakes or Cramp Balls

When we visited the Bluebell wood I mentioned in my last blog post, we found some fine examples of Cramp Ball fungi, Daldinia concentrica, also known as King Alfred’s Cakes.

Daldinia concentrica is a common and easily recognised fungus, found in Britain and Ireland and most of mainland Europe. The fungus also occurs in North America, Australia, New Zealand and many other temperate countries.

The specimens we found were growing on a fallen Ash tree (Fraxinus excelsior). This is where I have usually seen the fungus, though a study from 1982 says that the fungus is often associated with Birches (Betula) in Scotland. There are at least five species of Daldinia in Northern Europe and three of these grow on burnt wood. These include Daldinia fissa, which has smaller fruitbodies, grows on burnt Gorse (Ulex) stems, and Daldinia loculata, found very rarely on burnt Birch wood.

Daldinia concentrica is an Ascomycete fungus, in the family Xylariaceae. The First Nature website has some good photos of the fungus, its asci and its spores. The family contains other fungi that look like they’ve been burnt, including the wonderfully named Candlesnuff Fungus (Xylaria hypoxylon), Dead Man’s Fingers (X. polymorpha) and Dead Moll’s Fingers (X. longipes).

Which brings me to the name ‘King Alfred’s Cakes’. This refers to one of the best known stories in English history. When King Alfred was on the run from the Vikings he is said to have taken refuge in the home of a peasant woman. She asked him to watch her cakes (actually small loaves of bread) baking by the fire but Alfred was so distracted by his problems he let the cakes burn and the angry woman scolded him. The fruitbody of Daldinia concentrica does look like a burnt cake, or perhaps a lump of charcoal. Another English name is Coal Fungus.

Daldinia concentrica is a saphrotroph, living on dead and decaying wood. It is capable of discharging its spores even in dry conditions. Ash trees often shed their branches and by growing on these fallen branches, Daldinia concentrica helps them to rot away.

The fungus fruitbody is very hard and described as “not edible”. You might break your teeth if you tried. But it has other uses. Another name is Cramp Ball because carrying one was thought to cure attacks of cramps. If your cramp doesn’t get better, you could always use the fungus to help light a fire. It needs to be dry and black to do this. In India the fungus is called kala pihiri, meaning “black fungus” and is sometimes used to treat chronic coughs.

If you look at Daldinia concentrica in section you will see that it grows in concentric rings. These are darker than the flesh, which is more purplish-brown than black on its inside. The rings look rather like the growth rings in trees and, like tree rings, are thought to represent seasonal growth. They give the fungus its specific name of concentrica. The name Daldinia was chosen by the mycologists Cesati and De Notaris to honour their friend, the Swiss Catholic monk Agosto Daldini (1817- 1895). 

Daldinia concentrica contains several unique compounds. These include daldinone A and a purple polycyclic pigment and a metabolite called concentricol, which is oxidized squalene.