A very variable species in both colour and form. The pore structure is usually a good species indicator. Found on dead Oak & occasionally on other broad-leaved trees, solitary or in small overlapping groups. This perennial polypore appears with variable degrees of zoning, can be up to 200mm across, the upper surface can be smooth to uneven & furrowed. It is broadly attached to the substrate.
The pores are thick-walled, radially slotted to maze like & concolorous with the upper surface. The flesh is very tough, resembling cork or wood, buff brown. The tubes can be 40mm deep.