Trapeliopsis pseudogranulosa

Thallus effuse, often wide-spreading and forming large patches to 20 cm diam., grey- or green-white, in part patchily orange-pigmented, K+ purple, of granular areoles that can coalesce forming a faintly cracked granular crust; areoles mostly 40–200 µm diam. Soralia mostly 0.2–1.6 mm diam., green-white, in part orange- pigmented, at first convex and discrete, later coalescing and forming coarse, irregular patches; soredia 18–25 µm diam., farinose, tightly packed together. Apothecia very rare in our region, 0.4–1 (–1.6) mm diam., rare, ± appressed, flat with a shallow, wavy true exciple; disc green-grey to grey-black. Ascospores 10–12.5 × 3.5–6 µm. Thallus, soralia and apothecia C+ red, Pd–, UV–; orange pigmented areas of thallus and soralia K+ purple, UV± deep orange-red (gyrophoric acid and an unidentified anthraquinone).

Characterised by the minutely granular thallus, rather large farinose C+ red soralia and irregular, patchy orange coloration reacting K+ purple. The orange coloration can be rare or absent, in which case the thallus resembles that of Trapeliopsis gelatinosa, but that has a C– thallus and less tightly packed soredia. Thalli without the orange pigment may aslo be miss-rercorded as either Trapeliopsis flexuosa or T. granulosa but these have areolate thalli.