Description: Look to find this lichen on tree twigs and small branches, chiefly deciduous trees where it forms small white to grey coloured patches. The very pale brown discs become furred-up with pruina, like an icing-sugar topping on a cake, so appear white from above. A drop of fresh bleach (C) on the end of a toothpick will dissolve the pruina, turning the discs yellow.

Key Identification Features:

• White pruinose discs on a white thallus — twigs and branches mainly
• C+ yellow reaction (If C negative, then it is possible the species is Lecanora albella, a lookalike)

Original text submitted by Vince J. Giavarini

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

iNaturalist: Glaucomaria carpinea at iNaturalist World Species Observations database.