The inedible fungus ''Daldinia concentrica'' is known by several common names, including King Alfred's cake, cramp balls, and coal fungus. As with other fungi the light spores are distributed globally and the fungi develop wherever conditions are suitable - it lives on dead and decaying wood, and is a common, widespread
saprotroph
Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...
.
The fungus is ball-shaped, with a hard, friable, shiny black fruiting body 2 to 7 centimeters wide. It resembles a chunk of coal, which gives it several of its common names, including coal fungus and carbon balls. According to legend,
King Alfred
Alfred the Great (alt. Ælfred 848/849 – 26 October 899) was King of the West Saxons from 871 to 886, and King of the Anglo-Saxons from 886 until his death in 899. He was the youngest son of King Æthelwulf and his first wife Osburh, who ...
once hid out in a countryside homestead during war, and was put in charge of removing baking from the oven when it was done. He fell asleep and the cakes burned. ''Daldinia concentrica'' is said to resemble a cake left to this fate.
The flesh of the fungus is purple, brown, or silvery-black inside, and is arranged in concentric layers. Most sources agree that like
tree rings, these layers are related to seasonal growth.
The
asci are cylindrical and arranged inside the flask-shaped
perithecium
An ascocarp, or ascoma (), is the fruiting body ( sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are mos ...
. When each ascus becomes engorged with fluid it extends outside the perithecium and releases spores.
''D. concentrica'' contains several unique compounds, including a purple polycyclic pigment and a metabolite called concentricol, which is oxidized
squalene
Squalene is an organic compound. It is a triterpenoid with the formula C30H50. It is a colourless oil, although impure samples appear yellow. It was originally obtained from shark liver oil (hence its name, as ''Squalus'' is a genus of sharks). A ...
. Many types of insects and other small animals make their home inside this species of fungus.
Uses
The fungus is a useful form of tinder for fire-lighting. The brown variety is usually too heavy and dense to be much good; the black variety is lighter and better. It does need to be completely dry, whereupon it will take a spark from traditional
flint and steel. It burns slowly, much like a charcoal briquette, with a particularly pungent smoke. Once lit it usually requires constant oxygen flow to keep burning, such as through swinging the fungus or blowing on it. Fragments can be broken off to expose more embers and transferred to a tinder bundle to create an open flame.
Ecological value
Caterpillars of the
concealer moth ''
Harpella forficella
''Harpella forficella'' is a species of the concealer moth family (Oecophoridae), wherein it belongs to subfamily Oecophorinae.
Distribution
This species can be found in most of Europe and in the Near East.
Habitat
These moths inhabit deciduous ...
'' have been found to eat this fungus.
This fungus plays a pivotal role in accelerating the decomposition of the fallen branches of
ash trees
''Fraxinus'' (), commonly called ash, is a genus of flowering plants in the olive and lilac family, Oleaceae. It contains 45–65 species of usually medium to large trees, mostly deciduous, though a number of subtropical species are e ...
, which are naturally dropped very frequently.
References
*Glick, Phyllis (1979). ''The Mushroom Trail Guide''. 1st ed. New York, NY: Holt, Rinehart And Winston.
*Singh, Jagjit (1994). ''Building Mycology: Management of Decay and Health in Buildings''. UK: Spon Press.
External links
arkive.org page
{{Taxonbar, from=Q935453
Xylariales
Fungi of Europe
Fungi of North America