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
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. The smooth brown pore surface of this
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.
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.