Description: This bark epiphyte is frequent in valley woodlands where it grows alongside old woodland indicators such as Thelotrema lepidinum. It has a grey thallus (scratches orange = Trentepohlia algae) covered in whitish-grey, fleck-like scars that looks as though the tip of a needle has been puncturing the bark. These are the soredia which together with the thallus are K-, PD + orange. On oak and hazel, spreading to other smooth-barked trees. Mostly northern and south-western Ireland.

Key Identification Features:

• Whitish-grey fleck-like scars on a pale grey thallus, sometimes forming mosaics with Thelotrema lepadinum and Arthonia cinnabarina. Thallus and soredia Pd+orange
• Could only be confused with Pertusaria pupillaris which does not scratch orange and is K + dirty red.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Schizotrema quercicola at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Schizotrema quercicola at iNaturalist World Species Observations database.