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
tomentose 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. Spongipellis pachyodon in the field.
Photo © Mike Romankiewicz.


Figure 2. Individual caps and effused portions of
Spongipellis pachyodon may fuse together to form large
sheetlike fruit bodies. Photo © Mike Romankiewicz.

Figure 3 Dried herbarium specimen of Spongipellis
pachyodon. Photo © Gary Emberger.

Figure 4. Effused-reflexed fruit body of Spongipellis
pachyodon. The teeth are decurrent onto the effused
portion of the fruit body. Photo © Gary Emberger.


Figure 5. The flattened teeth of Spongipellis pachyodon
may be quite long, up to 12 mm or more in length.
Photo © Mike Romankiewicz.


Figure 6. Sectioned cap revealing the white context and
the teeth on the cap and effused portions of the fruit body.
Photo © Gary Emberger.