Brittle Cinder – Kretzschmaria deusta

Fungi of the Week

21st February 2020 | Info

Common name:Brittle Cinder 

Scientific name:Kretzschmaria deusta 

Introduction:The Brittle Cinder (Kretzschmaria deusta) is an ascomycete fungus that is commonly found in the UK.  


Fruiting-body:When first forming, the fruiting body is grey and begins to develop a black, lumpy, charcoal-like wavy crust within the first year. This crust then remains but doesn’t grow further. Smaller-fruiting bodies form around the outer edge of the black-crust and turn to powder when crushed.  

Condiospores:Asexually produced with a pip-like shape. 

Ascospores: Ellipsoidal and produced in the summerleaving a black spore-print behind.  



They form close to the ground on lower stem buttresses and principle roots on a range of broadleaved trees, especially species such as beech, lime and maples.

Impact on Trees

Brittle Cinder are parasitic on the roots and lower trunks of living hardwood trees and can cause soft-rot when they first form. They consume the cellulose of the timber of a tree once the host has died, causing the wood to become brittle [hence the name]. It can also lead to white rot. Unusually though, there are typically no warning signs, unlike most cases with white-rot fungus such as bulging and cracking.

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