Daldinia concentrica

Good afternoon, friends,

This week’s mushroom is from the Genus Daldinia and was found in the ramble on 8/5/2021. The species is most likely D. childiae, but we can’t definitively say that without microscopic analysis or DNA sequencing. This species used to be called D. concentrica, which was found to be an exclusively European species, and further research has shown several different species may be grouped under both D. childiae and D. concentrica. Nevertheless, we have plenty of fun facts and interesting ecological features to highlight.

Fun Facts

The European D. concentrica goes by the common names carbon balls, cramp calls, coal fungus, and King Alfred’s cakes. The last name dates to an old English legend where King Alfred (ruler from 871-899) was on the run from the vikings and took shelter in a peasant woman’s house while she was baking cakes (loaves of bread on this side of the pond). Unaware of his royal identity, she tasked him with watching the cakes as they baked. Presumably preoccupied with his viking predicament, the cakes burned – to the point where they looked like Daldinia – and he was, rightfully, scolded.

The other common name, cramp balls, comes from the idea that carrying Daldinia around in your pocket – or under your armpits (?) – will help alleviate leg and menstrual cramps. I couldn’t find any substantial information to confirm or deny this so I think we should focus on maintaining proper hydration and electrolyte levels for now.

The name coal fungus relates to its ability to carry a flame. When dry, the balls can hold and carry an ember if sparked by flint & steel. Perhaps useful if you’re in a survival situation. When you’re not relying on them to ward off frost bite, it may be an interesting experiment to use a lighter and see how long a single ball will burn.

The rings above are where the European species D. concentrica gets its name. The rings are said to be indicative of seasonal growth, like tree rings, but I’ve also heard that they are used for storing water. The outermost ring contains perithecia which releases spores through a small opening known as an ostiole.

Above is a graph of taxonomic rank (from Wikipedia) which will be a helpful reference for this next section.


Fungi in the genus Daldinia are in the phylum ascomycota. The majority of fungi featured on MM are in the phylum basidiomycota, but Xylaria liquidambaris and Biscogniauxia marginata are both examples of other ascomycetes.

Basidiomycota and Ascomycota are the two major phyla of fungi (out of seven total phyla), and ascomycetes comprise the majority of the Kingdom/Queendom – accounting for ~75% of all described fungal species. The major difference in the two phyla is how they produce their spores (as an aside both phyla have fungi capable of asexual reproduction). Without boring you with more underlined vocabulary, basidiomycetes develop their spores externally in specialized structures. Conversely, ascomycetes (referred to simply as ascos by those in know – like you) develop their spores internally in a sack (called an ascus) where pressure builds until the top of the sack ruptures and spores are projected into the environment. The highest reported acceleration of any organism across any kingdom belongs to an asco (giberella zeae) which releases spores at 8,500,000 m/s^2 (reference 4).

D. childiae is found across North America, particularly east of the Rockies, and grows spring through fall. It is saprobic on hardwoods – and it looks like the specimen here is growing on black locust (Robinia pseudoacacia). It’s also noted that it is frequently found on ash trees, and with emerald ash borers afflicting ash trees across eastern North America there will be plenty of Daldinia food for decades to come. The black dust covering them – most notable in the first picture – are the spores.

Have a stellar week,

1) Kuo, M. (2019, October). Daldinia childiae. Retrieved from the MushroomExpert.Com Web site: http://www.mushroomexpert.com/daldinia_childiae.html
2) McCoy, Peter. Radical Mycology: A Treatise on Seeing & Working with Fungi. , 2016. Print. Pages 7-10.
3) https://www.royal.uk/alfred-great-r-871-899
4) Frances Trail, Fungal cannons: explosive spore discharge in the Ascomycota, FEMS Microbiology Letters, Volume 276, Issue 1, November 2007, Pages 12–18, https://doi.org/10.1111/j.1574-6968.2007.00900.x
6) https://www.inaturalist.org/taxa/350616-Daldinia-childiae