Fruiting body annual to perennial, sessile, 5-15 cm broad, 1.5-3.0 thick, more or less fan-shaped, often forming overlapping shelves; margin when young, yellowish to yellow-brown, pubescent, elsewhere the cap surface rusty-brown to dark-brown, sometimes zonate, tending to be glabrous, but often bumpy or concentrically furrowed; flesh tough, zonate, yellow to ochraceous brown, darkening in KOH.
Pores 5-7 per mm, circular, mouths rusty-brown, darkening in KOH; tubes up to 0.7 cm long, if perennial, multi-seried.
Spores 4.5-5 x 3-3.5 µm, oval to elliptical, smooth, nonamyloid; spores white in deposit.
In small groups or overlapping tiers on dead hardwoods; found year-round, new fruiting bodies and fresh growth appearing after the fall rains.
Too tough to be eaten.
Phellinus gilvus is our most common conk on oaks (Quercus) and tanbark oak (Lithocarpus densiforus). Its preference for hardwoods plus a distinctive yellowish-brown pubescent growing margin with contrasting, furrowed to bumpy, brown cap, and rusty-brown pore surface, make it fairly easy to identify.