Physciaceae Phaeophyscia orbicularis Orange-yellow patches on cortex and soredia K+/- purple. Medulla: K- Common on nutrient-rich bark, twigs, stones and on concrete and roads. Host to Arthonia phaeophysciae and Lichenochora obscuroides Pale grey to brownish-grey orbicular thallus, becoming green when wet. Long, divided lobes with black undersides and dark, protruding rhizines. Laminal and marginal dense creamy-greenish soralia, mottled bluish-black. Apothecia occasional, spores brown, 1-septate, 17-26 x 7-11 µm. Microscope photograph below. Similar: Hyperphyscia adglutinata. Under surface white with few rhizines. Physcia caesia, larger globose soralia and Physcia tribacioides

Microscope photograph

Phaeophyscia orbicularis
Dorset. 2012-2014