Perenniporia fraxinophila

Scientific name:   Perenniporia fraxinophila (Pk.) Ryv.
Derivation of name:   Perenniporia means "a polypore with
perennial fruiting bodies"; fraxinophila means "ash loving" in
reference to its most common host, ashes (Fraxinus).
Synonymy:   Polyporus fraxinophilus Pk.; Fomes
fraxinophilus (Peck) Sacc.
Common names:  
Phylum:   Basidiomycota
Order:   Polyporales
Family:   Polyporaceae
Occurrence on wood substrate:  Parasitic; solitary or in
overlapping clusters on the trunks of living deciduous trees,
especially ash (Fraxinus); year-round.  
Dimensions:  Caps up to 9 cm wide; 7 cm long, 7 cm thick.   
Upper surface: Grayish-black; glabrous; cracked;
concentrically furrowed.
Pore surface: Ivory to buff; pores 3-5 per mm.
Edibility: Inedible.
Comments: This perennial species is the major cause of trunk
rot in living ash trees.

    
Figure 1. Note the cracked, blackish older portion of
Perenniporia fraxinophila on this ash tree.
Photo © Tom Volk.

Figure 2. Pore surface of Perenniporia fraxinophila.
Photo © Tom Volk.