Scientific name: Phellinus robiniae (Murrill) A. Ames
Derivation of name: Phellinus means "made of cork"or
"corky"; robiniae means "growing on black locust (Robinia
Synonymy: Fomes rimosus (Berk.) Cooke; Fomes robiniae
(Murr.) Sacc.; Pyropolyporus robiniae Murr.; Polyporus
Common names: Cracked cap polypore.
Occurrence on wood substrate: Saprobic and
solitary or scattered primarily on living or
dead black locust
pseudoacacia) ; year-round.
Dimensions: Caps 5-40 cm wide (or wider).
Upper surface: Yellowish-brown to brown, becoming
in age; deeply cracked in age; concentrically
Pore surface: Yellow-brown to reddish-brown; pores
Comments: Several other polypores develop cracks in
few occur on black locust.
Figure 1. Specimens of Phellinus robiniae on black
locust. Photo © Gary Emberger.
Figure 2. Note the deeply cracked (rimose) surface of the
cracked cap polypore. Photo © Gary Emberger.
Figure 3. A very large, old specimen 37 cm wide.
Photo © Gary Emberger.
Figure 4. The same specimen pictured in Figure 3 showing
moss and lichens growing on
top of the cap.
Figure 5. The smooth brown pore surface of this
is 47 cm wide. 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.