Phellinus robiniae

Scientific name:   Phellinus robiniae (Murrill) A. Ames
Derivation of name:   Phellinus means "made of cork"or
"corky"; robiniae means "growing on black locust (Robinia
pseudoacacia)."
Synonymy:   Fomes rimosus (Berk.) Cooke; Fomes robiniae
(Murr.) Sacc.; Pyropolyporus robiniae Murr.; Polyporus
rimosus Berk.
Common names:   Cracked cap polypore.
Phylum:   Basidiomycota
Order:   Hymenochaetales
Family:   Hymenochaetaceae
Occurrence on wood substrate:  Saprobic and
parasitic; solitary or scattered primarily on living or
dead black locust (Robinia pseudoacacia); year-round.
Dimensions: Caps 5-40 cm wide (or wider).    
Upper surface: Yellowish-brown to brown, becoming
blackish in age; deeply cracked in age; concentrically
furrowed.
Pore surface: Yellow-brown to reddish-brown; pores
7-8 per mm.
Edibility: Inedible.
Comments: Several other polypores develop cracks in
age but few occur on black locust.

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Figure 1. Specimens of Phellinus robiniae on black
locust. Photo © Gary Emberger.

Figure 3. The smooth brown pore surface of this
specimen is 47 cm wide. Photo © Gary Emberger.

Figure 4. A very large, old specimen.
Photo © Gary Emberger.

Figure 5. The same specimen pictured in Figure 4 showing
moss and lichens growing on top of the cap. Photo ©
Gary Emberger.

Figure 6. Phellinus robiniae is perennial and looks about
the same any time of the year, even with snow on it.
Photo © Larry Grand.


Figure 7. This sectioned specimen shows the layers of
tubes formed by perennial polypores such as Phellinus
robiniae. Photo © Gary Emberger.