Ustulina deusta

Scientific name:  Ustulina deusta (Hoffm.) Lind
Derivation of nameDeusta means "burned up" in reference
to the charred appearance of the fungus.  
SynonymsSphaeria deusta Hoffm.; Kretzschmaria deusta
(Hoffm.) P.M.D. Martin 
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.  

Figure 1. Immature (asexual) and mature (sexual) stages of
carbon cushion. Photo © William Roody.

Figure 2. The asexual stage of Ustulina deusta.
Photo © Steve Nelsen.

Figure 3. This is how carbon cushion appears detached
from the wood substrate. The rough, lumpy black surface
is typical of the perithecial stage.
Photo © Gary Emberger.

Figure 4. Looking closer at the rough surface reveals the
presence of numerous pimple-like bumps.
Photo © Gary Emberger.

Figure 5. A closer view of Figure 4. The bumps 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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