| Macroscopic characters | shape | Applanate; dimidiate; basidiocarps often fusing together |
| size | Up to 23 x 35 x 15 cm; and even larger |
| texture | Fibrous; somewhat tough |
| pileus | Buff to dark brown; rimose with age; amber drops when fresh leaving circular pits; finely tomentose or glabrous |
| stipe | N/A |
| context | Bright yellowish-brown; reddish brown in age |
| pore surface | Buff; often exuding amber droplets; becoming dark brown with age |
| pores | Circular or angular; 4-6 per mm |
| tube layer(s) | Up to 2 cm deep |
| Microscopic characters | hyphal system | Monomitic; but with thick-walled contextual hyphae |
| clamp connections | Present on generative hyphae |
| sterile elements | Setae frequent; occasionally difficult to find; usually hooked; ventricose |
| basidiospores | Subglobose hyaline; smooth; thick-walled in age; cyanophilous; 6-8 x 5-7 um |
| Habitat characters | substrate/host | Mainly on mature oaks in eastern North America; on true firs in the Pacific Coast Region and Southwestern U.S. |
| seasonality | Annual |
| type of decay | White rot of heartwood in butts and roots of living oaks and true firs |
| range | Throughout the eastern hardwood forests with oaks and also in the Southwest and Pacific Coast conifer forest ecosystems with true firs |
| Notes | Typically develop at the ground line at the base of infected trees or from roots and some distance from the base |
| References | Overholts, 1953; Gilbertson & Ryvarden, 1986 |
