Description: A very distinctive lemon-yellow to yellow-orange crustose lichen. It forms neat thalli with elongate radiating lobes and irregular granular isidia towards the centre of the thallus. Apothecia are very rare. This species is characteristic of nutrient-enriched sites such as bird-perching rocks. It resembles Caloplaca thallincola but that species has a much brighter orange thallus and has apothecia rather than isidia.

Key Identification Features:

• Lemon-yellow to orange-yellow colour.
• Neat, elongate, radiating lobes.
• Granular isidia towards centre of thallus. Apothecia rare.
• Exclusively marine. Typical of nutrient-enriched sites.

Original text submitted by Michael J. Simms

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

iNaturalist: Polycauliona verruculifera at iNaturalist World Species Observations database.