A thin, leathery annual bracket, with a pale, zonate upper surface with felted hairs. The fertile surface underneath is pale cream, darkening with age; pores initially rather maze-like but becoming gill-like later; 10 - 15 per cm. at the margins. 

Other mazegills.

Photograph upper and lower fertile surface to show pores; note host plant and substrate

Mainly Birch but sometimes on other deciduous trees

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Common and widespread.

Uncommonly recorded.