Kretzschmaria deusta

Scientific name:  Kretzschmaria deusta
(Hoffm.) P.M.D. Martin
Derivation of nameDeusta means "burned up" in reference
to the charred appearance of the fungus.  
SynonymsSphaeria deusta Hoffm.; Ustulina deusta
(Hoffm.) Lind
Common name(s):  Carbon cushion
Phylum:   Ascomycota
Order:   Xylariales
Family:   Xylariaceae
Occurrence on wood substrate:  Saprobic; forming crust-
like sheets on stumps and dead roots of deciduous trees; year-
Dimensions:  Fruitbody 4-10 cm wide, 3-5 mm thick,
forming sheets up to 50 cm long that are irregular in shape.  
Description: Fruitbodies at first grayish-white, soft and
powdery. This stage is the asexual stage. With maturity, the
fruitbody becomes hard, black, and finely roughened with the
bumplike pores of perithecia embedded in a whitish flesh.
These crust-like fruitbodies are brittle and easily detached from
the wood.       
Edibility: Inedible.   
Comments:  At maturity, this fungus resembles burnt wood.  

More information at

Figure 1. Occurrence of Kretzschmaria deusta on dead
wood. Photo © Patrick Harvey.

Figure 2. An award-winning photograph of Kretzschmaria
illustrating the grayish-white asexual stage of the
fungus. Photo © Patrick Harvey.

Figure 3. The asexual stage of Kretzschmaria
deusta. Photo © Steve Nelsen.

Figure 4. Immature (asexual) and mature (sexual) stages of
carbon cushion. In contrast to the soft, grayish-white
asexual stage, the sexual stage is black and crust-like.
Photo © William Roody.

Figure 5. The black sexual stage of carbon cushion.
Photo © Joanne Solem.

Figure 6. The rough, lumpy black sexual (perithecial) stage
stage of carbon cushion is easily detached from the wood
substrate. Photo © Gary Emberger.

Figure 7. A closer view of the rough surface reveals the
presence of numerous pimple-like bumps.
Photo © Gary Emberger.

Figure 8. The bumps of Figure 7 are the pore-like openings
of perithecia embedded just under the surface. Within
each perithecium are asci with ascospores.
Photo © Gary Emberger.


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