Pseudocyphellaria aurata (Sm.) Vain.
Sticta aurata Ach.
Thallus foliose, more or less regular rosette-shaped, lobes 5-10 mm wide, apices slightly rounded and wavy, margins covered with bright yellow granulose soralia potentially spreading to the whole lobe; upper surface smooth to slightly undulating, bright green, green-yellowish when moist, pale green-greyish when dry lower surface minutely rough and slightly tomentose, pale brown-pink, darker towards the lobe center, yellow pseudocyphella present, 0.1-0.6 mm diam.. Fertile specimen unknown in our prospection area, apothecia sessile, disc concave, smooth, brown-reddish, exciple with bright yellow soralia. Ascii utriform, 8-spored, 55-70 x 18-25 µm according to our measures. Ascospores ellipsoid, brown, apices pointed, 3-septate, (15) 20-30 (35) x (6) 7-8 µm according to our measures. Photobiont: green algae. Chemical spot test negative. Oceanic and Macaronesian, on mossy rocks and trees, sometimes on Calluna. Emblematic species, often reported in ancient times in our prospection area, but currently very rare and endangered, sampling prohibited (a unique site known on a Fagus high up on trunk in Finistère).