Hypogymnia farinacea
Thallus to 5 cm diam., closely appressed, forming poorly defined rosettes or irregularly spreading. Lobes 1-3 mm wide, hollow, ± convex but flattened towards the ends, contiguous and overlapping, sometimes intricately convoluted in the centre, often ± discrete towards margins; upper surface grey-green, wrinkled except at the thallus edge which is brownish and with a network of pale pseudocyphella-like lines on the upper surface. Soralia spreading, laminal, forming on the ridges of the wrinkles. Lower surface black.
Anamorph: not observed.
Teleomorph: ascomata apothecia, not observed in British material.
Chemistry: cortex K+ yellow; medulla C–, K–, KC+ red, Pd–, UV+ pale violet-blue (chloroatranorin, atranorin, physodic and 3-hydroxyphysodic acids, and some unknowns).
Assessed as Near Threatened by Woods & Coppins (2012). It has been suggested that the species is a recent arrival in Great Britain, but more information is needed.
Distinguished by the diffuse, laminal, Pd– soralia.
Restricted to highland Britain, reported from the NW Highlands (W Ross), the Cairngoms and Cumbria.
Primarily on trunks of Pinus in relict Caledonian forests, with outlying occurrences on boulders.