Xylobolus frustulatus

Scientific name:  Xylobolus frustulatus (Pers.) Boidin
Derivation of name: frustul means "a little piece."
Synonyms:  Stereum frustulatum (Pers.) Fr.
Common name(s):   Ceramic parchment
Phylum:   Basidiomycota
Order:   Russulales
Family:   Stereaceae
Occurrence on wood substrate:  Saprobic; clustered on
hardwood logs, particularly oak; year-round. 
Dimensions: Individual fruitbodies 0.3 to 2 cm wide.    
Description: Fruitbodies occur as crowded, polygonal, woody
plates that resemble broken pieces of tile. The fertile surface is
pinkish-buff to whitish and the outer, sterile surface is
blackish. Colonies of these fungi can cover considerable areas
of wood.      
Edibility: Not edible.  
Comments: Most commonly found on old decorticated oak
logs and stumps.

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Figure 1. Appearance of ceramic parchment on an oak log.
Photo © Gary Emberger.

Figure 2. Xylobolus frustulatus on oak.
Photo © Gary Emberger.

Figure 3. The wood supporting the growth of Xylobolus
frustulatus is typically quite intact, making it very difficult to
remove a specimen using just a small knife.
Photo © Gary Emberger.

Figure 4. Many individual fruitbodies are typically clustered
together like broken pieces of tile.
Photo © Gary Emberger.

Figure 5. The light-colored surfaces bear basidia.
Photo © Gary Emberger.

Figure 6. Note how tightly clustered the individual "tiles"
are. Photo © George Barron.

Figure 7. In these unusual specimens, the blackish, sterile surface
has formed cap-like structures extending over the light-colored
fertile surfaces. Photo © Tom Bigelow.

Figure 8. These ceramic parchment specimens have been colonized
by Hypomyces xyloboli which produces greenish, asexual spores
(i.e., conidia). Photo © Tom Bigelow.