King Alfred’s Cake – Daldinia concentrica

Fungi of the Week

7th October 2019 | Info

Common name: King Alfred’s cake

Scientific name: Daldinia concentrica

Introduction: Daldinia concentrica is a flask fungus also commonly known as ‘Cramp Balls’ and ‘Coal Fungus’.


Cap: Begins brown and dense but as it matures it turns black and begins to dry out, becoming less dense. The surface of the fungus is spore-bearing.

Stem: Stemless.

Spores: When young (have brown-pink coloured fruiting bodies), colourless conidiospores (conidia) are released and appear with a pink-whiteish tinge when seen in large amounts. Once the fungus has matured (has a black fruiting body), its spores are released from perithecia chambers having been produced by asci. They are ellipsoidal to fusiform in shape and are black in colour. Additionally, Ascospores are also released and can appear as black dust or in a rope-like form.  

Flesh: Dense when young but dries out as the fungus matures. It is hard and has concentric rings. 

Group: Xylariaceae. 

Habitat: Grows and lives on dead and decaying wood. Typically Ash and Beech trees.

Impact on Trees/Ecological importance: King Alfred’s Cakes are Saprobic meaning that they feed on dead or decaying wood – specifically of Ash trees. 

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