Description: This small, crustose epiphyte with a thin, dark brown thallus is commonly encountered sterile, that is, without its slit-like discs. It is recognised by its abundant sprinkling of small, beige to orange-yellow, powdery soralia. It is relatively common on the deciduous bark of trees such as sallow, especially in marshy or swamp-like habitats.

Key Identification Features:

• It may be confused with the less common Opegrapha multipuncta that has yellower, often confluent soralia that react C-
• Opegrapha sorediifera is C+ red, and the soralia are UV+ red. Opegrapha corticola is also similar, but has larger, duller beige soralia that are C-.

Original text submitted by Simon Davey

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

iNaturalist: Zwackhia sorediifera at iNaturalist World Species Observations database.