Family: Arthoniaceae Species: Naevia punctiformis (Arthonia punctiformis) Growth type crustose. Epithecium K+ pale green. Photobiont absent Photos: On Bog-myrtle, Commeen West, Co. Cork, SW Ireland Immersed thallus, sometimes slightly bleaching the bark, photobiont absent. The small black apothecia are usually immersed and with thin margin of bark cells. Spores 3(-5) septate, 13-23 x 5-7 µm, colourless, the upper cell not enlarged. Micrograph below. A pioneer species on twigs and the smaller branches of trees and shrubs, where it is often found with Naetrocymbe punctiformis (Arthopyrenia punctiformis) Similar: Arthonia radiata has a lichenised thallus containing Trentepohlia and the apothecia are often branched

Micrograph

Naevia punctiformis, Arthonia punctiformis. June 2025