Lecanoraceae Lecanora gangaleoides Growth type crustose Chemical results: K+ yellow, P+ orange, UV- or pale orange. Apothecia greenish-brown in section, the thecium dark greenish. Scratching the discs or thallus reveals orange anthraquinones. Mainly coastal, on siliceous rocks. Green-grey smooth or warted thallus with a white prothallus. Black convex discs with wide thalline margin, the thecium dark greenish. Lower medulla scratches orange. Microscope photograph below. Similar: Tephromela atra, thecium purplish, UV+ bluish-white

Microscope photograph

Lecanora gangaleoides
Portland, Dorset. February 2016