The upper surface is usually gray or white, but may be greenish in older specimens due to algal growth.

Trametes gibbosa grows as a shelf mushroom and can can reach sizes of up to 20 cm wide.

This upper surface is white/creamy when young, but often develops greyer tints as well as green from algae settling into the hairs.

The pore surface is of similar white and cream colors, also developing grayer tints in age.

"Spores 4-5.5 x 2-2.5 μm, elliptic-cylindrical, smooth, hyaline, inamyloid, hyphal system trimitic, clamp connections present"[1] T. gibbosa is saprobic on dead hardwoods and is known from Eurasia and North American pacific north-west and east of the great plains.

[1] The hairy and lumpy cap, the elongated pores, and the shelf-like growth are all important features that help narrow down the identification to T. gibbosa.

The genus Trametes can be separated from other polypores by the hairy caps, the fan to kidney shape, and their relative thinness.

Whitish or grey specimens of Trametes lactinea can seem similar, but will have round or angular pores, rather than elongated.