Description: This crustose, bark epiphyte is a frequent colonist of mature, acid-barked tree boles, especially oak. Typically, it comprises a white to greyish thallus, with white powdery-tipped, stick-like pycnidia (easily confused with isidia) scattered across it. Discs are brownish and heavily grey pruinose where not rubbed against. The pycnidia should be tested with a dab of fresh bleach which should turn them red.

Key Identification Features:

• The white-grey thallus sprinkled with stick-shaped pycnidia that test C+ red confirms this species
• It is most likely to be confused with two similar species with powdery white pycnidia
• Lecanactis subabietina differs in having blunter-tipped pycnidia that are C negative and Opegrapha vermicellifera which may look similar, but occurs usually on more basic-barked trees, for example, sycamore and is also C negative.

Original text submitted by Simon Davey

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

iNaturalist: Lecanactis abietina at iNaturalist World Species Observations database.