Roccellaceae Roccellographa circumscripta (Peterjamesia circumscripta, Sclerophytomyces circumscriptus) Growth type crustose. BLS conservation evaluation: NS Chemical results: K-, C-, KC+ pale yellow, P+ yellow-orange, UV-. Photobiont Trentepohlia Coastal, in dry shady underhangs of sheltered acidic rocks, intolerant of direct wetting by sea spray or rain Thin, whitish or grey-mottled, scurfy thallus (scratching orange-yellow), finely cracked and surrounded by grey-black prothallus. Numerous dot-like apothecia, discs black and often densely pruinose. Spores 17-26 x 5-6 µm Similar: Ingaderia sorediata (Peterjamesia sorediata)

Roccellographa circumscripta
On chert, Portland, Dorset. February 2016