Spongipellis pachyodon

Scientific name: Spongipellis pachyodon (Pers.) Kotl. &
Pouz. 
Derivation of name: Pachyodon means "with thick teeth."  
Synonyms: Hydnum pachyodon Pers.; Irpex mollis Berk
& M.A. Curtis  
Common name(s): None.  
Phylum:   Basidiomycota
Order:   Polyporales
Family:   Hapalopilaceae
Occurrence on wood substrate: Parasitic and saprobic;
effused-reflexed, spreading, single or overlapping caps on
fallen logs and living hardwoods, particularly oak; from July
through October, overwinters.   
Dimensions: Individual caps 2.5 to 5 cm wide and long with
individual caps and effused portions fusing to form larger
sheets 20 cm or more wide. Context up to 1 cm thick.  
Description: Stalkless caps are white to ochraceous; finely
pubescent to glabrous; white to ochre tubes initially poroid
but eroding to form flattened and cylindrical teeth 0.5 to 12
mm in lengh; teeth often decurrent onto effused portions.   
Edibility: Inedible. 
Comments: As reflected in the order name, Polyporales,
Spongipellis pachyodon is actually a poroid fungus. Several
other poroid fungi (see Poroid Group A key) have pores
which break down to form teeth. This parasite causes a
white heart-rot of living broadleafed trees, particularly oak.


Figure 1. Individual caps and effused portions of
Spongipellis pachyodon may fuse together to form large
sheetlike fruit bodies.

Figure 2. When very young, this organism forms tubes with
pores (not visible here). These soon become toothlike.

Figure 3. Effused-reflexed fruit body of Spongipellis
pachyodon. The teeth are decurrent onto the effused
portion of the fruit body.

Figure 4. Sectioned cap revealing white context and teeth.
Teeth near the margins are flattened while those near the
center are cylindrical and tapering.