King Alfred’s Cakes

(Daldinia concentrica)

Conservation Status

IUCN Red List

not listed


not listed


not listed

King Alfred’s Cakes
Photo by Paul

King Alfred’s Cakes is a common fungus that occurs on all continents except Greenland and Antarctica. It grows singly, in groups, or in masses, on dead or dying deciduous wood (saprobic), especially ash. It causes a white rot that produces a condition known as “calico wood”.

The fruiting body is ¾ to 3¾ in diameter and stalkless. It is usually ball-shaped, sometimes irregularly shaped, especially when growing in groups. When young, it is brown and dense, and it releases asexual spores (conidia) on its surface. The conidia are colorless but may appear whitish when massed. The flesh is dense and purplish-brown. At maturity the surface is black, shiny, and densely covered with minute, pimply bumps. These bumps are tiny, spore-bearing chambers (perithecia) just under the surface. When the spores are mature, the perithecia bursts open during the night, ejecting up to an inch or more large numbers of black spores. These spores are often visible on the bark near the fungus long after they have worn off the fruiting body. Spores are produced from late spring to late fall.

King Alfred’s Cakes is long lived and continues growing over several years. Each year a new outer surface is formed. Slicing it vertically reveals black and white concentric rings, each ring representing an entire growing season. The flesh is hard or corky and easily crumbled, becoming less dense as it ages. It is not edible.

The spore print is black. A natural spore print can often be seen on the bark near the base of the fungus.


Similar Species

Habitat and Hosts

Dead deciduous wood



Year round


Distribution Map



4, 24, 26, 29, 30, 77.



Common and very widespread



Fungi (fungi)




Ascomycota (sac fungi)














Subordinate Taxa

Daldinia concentrica ssp. concentrica

Daldinia concentrica ssp. intermedia

Daldinia concentrica var. concentrica

Daldinia concentrica var. pedicellata



Daldinia atra

Daldinia concentrica f. confluens

Daldinia concentrica f. intermedia

Daldinia concentrica var. microspora

Daldinia concentrica var. minuta

Daldinia tuberosa

Daldinia vernicosa f. microspora

Fungus fraxineus

Gamosphaera concentrica

Hemisphaeria concentrica

Hemisphaeria tuberosa

Hypoxylon concentricum

Hypoxylon tuberosum

Lycoperdon atrum

Lycoperdon fraxineum

Peripherostoma concentricum

Peripherostoma concentricum var. multicapsulare

Sphaeria concentrica

Sphaeria concentrica var. pedicellata

Sphaeria fraxinea

Sphaeria tuberosa

Sphaeria tunicata

Stromatosphaeria concentrica

Valsa tuberosa


Common Names

Coal Fungus

Cramp Balls

King Alfred’s Cakes









An asexual spore produced by some fungi.



A term often used for saprotrophic fungi. Referring to fungi that obtain their nutrients from decayed organic matter.






Fire Starter

King Alfred’s Cakes is also called Coal Fungus, but not just for its appearance. An older, black specimen, when broken to expose the interior, will readily take a spark from a fire steel. Blow on the glowing spark and it will grow in size. Left alone, it will smolder for a long time. Placed against dry tinder and blown upon, it will ignite a fire.





What’s in a Name?

The common name “Cramp Balls” refers to the belief that when carried in a pocket it can prevent or cure leg cramps. The common name King Alfred’s Cakes refers to a story told about a British monarch. King Alfred fled from a battle and took refuge in a peasant woman’s house. The woman asked him to watch her cakes in the oven. Preoccupied with his own troubles, he let the cakes burn. This earned him a scolding from the woman who did not know her visitor was the king.

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King Alfred’s Cakes   King Alfred’s Cakes
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Silverwood Gardens

King Alfred’s Cakes  


At first glance I thought it was scat, but when I picked it up, it was definitely fungi.




King Alfred’s Cakes    
Fungi on decaying log.  


King Alfred’s Cakes   King Alfred’s Cakes
King Alfred’s Cakes   King Alfred’s Cakes
King Alfred’s Cakes   King Alfred’s Cakes
King Alfred’s Cakes   King Alfred’s Cakes Photos




Daldinia concentrica, King Alfred's Cakes or Cramp Balls

Daldinia concentrica, King Alfred’s Cakes or Cramp Balls

Daldinia concentrica
Amadej Trnkoczy

Daldinia concentrica

Daldinia concentrica (Bolton) Ces. & De Not., syn.: Daldinia intermedia (Lloyd) Child, Hypoxylon concentricum (Bolton) Grev., Valsa tuberosa Scop., Sphaeria tuberosa (Scop.) Timm

Carbon Balls, Coal Fungus, Cramp Balls, King Alfred's Cakes, DE:
Slo.: slojevita oglarka
Dat.: July 6. 2010
Lat.: 46.17522 Long.: 13.72071
Code: Bot_433/2010_IMG1243

Habitat: wood edge, hop hornbeam (Ostrya carpinifolia) dominant tree; not far from river bank; almost flat terrain; calcareous, alluvial ground; half shade, relatively warm place; exposed to direct rain; average precipitations 2.000-2.600 mm/year, average temperature 10-12 deg C, elevation 185 m (600 feet), borderline between alpine and sub-mediterranean phytogeographical region.

Substratum: fallen, dead and partly disintegrated thick branch of broadleaved tree, most probably Fagus sylvatica, possibly Acer spp.

Place: Tolmin region; southwest of the town and southeast of rubbish dump Volče, right bank of river Soča, Posočje, Slovenia EC.

Comments: Daldinia concentrica is a quite common ascomycete, also in Slovenia. Its 'balls' are reddish or rusty-brown at first becoming black and shiny resembling charcoal. Flesh is conspicuously concentrically zoned when cut vertically. One can find it mostly on Fagus sylvatica but also on other broadleaved trees. There appears little possibility to misidentify it in Slovenia since all other species of the genus Daldinia are very rare.

English vernacular name King Alfred's Cakes is based on the following legend. King Alfred was hiding in a country home during war time. Unaware of his identity, the mistress of the house put him in charge of watching the baking of the cakes in the oven. King fell asleep and the cakes burned. Daldinia concentrica apparently resembles these cakes.

Growing gregariously in several groups all along the fallen branch. Tens of fruit bodies present.

(1) G. Medardi, Atlante fotografico degli Ascomiceti d'Italia, A.M.B. Centro Studi Micologici (2012) (in Italian with English keys), p 321.
(2) M.W.Beug, A.E. Bessette, A.R. Bessette, Ascomycete Fungi of North America, University of Texas Press, Austin (2014), p 293.
(3) R. Phillips, Mushrooms, Macmillan (2006), p 375.
(4) J. Breitenbach, F. Kraenzlin, Eds., Fungi of Switzerland, Vol.1. Verlag Mykologia (1984), p 274.


Reply to Flickr comment:
mangosteen queen 12h

What are those white flecks on the fruiting bodies? (relate to Daldinia concentrica observation)

First I thought they are some kind of seeds and haven't paid much attention to them. But, motivated by your question, zooming maximally into my high resolution pictures reveals this was wrong. Seems the things are attached to the surface of the fungus. They don't seem to me to be of fungal origin. I would guess they are of insect origin. Either some kind of eggs or cocoons. One of them seems to be already empty. Interesting! But I am too ignorant to say more. See the last (added) picture to the album Daldinia concentrica.



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Other Videos

Daldinia concentrica


Published on Jun 10, 2012

Daldinia concentrica tinder fungus

King Alfred's cake (Daldinia concentrica) - 2017-04-24


Published on Jun 29, 2017

The inedible fungus Daldinia concentrica is known by several common names, including King Alfred's cake, cramp balls, and coal fungus. It can be found in North America, South America and Europe, where it lives on dead and decaying wood, especially on felled ash trees. It is a common, widespread saprotroph.

Geo location: 51.97683 4.16942



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Location: Lake Shore

Fungi on decaying log.

King Alfred’s Cakes
Silverwood Gardens
September - October 2021

Location: Northfield, Rice County, MN

At first glance I thought it was scat, but when I picked it up, it was definitely fungi.

King Alfred’s Cakes

Location: Fairview Township, Cass Cty.

King Alfred’s Cakes

Location: Cass County

King Alfred’s Cakes Sightings






Created: 11/20/2018

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