Chrysothrix flavovirens Tonsberg
Thallus inconspicuous or very thin, spreading on the substratum without distinct prothallus, whitish to very pale grey, rapidly covered with numerous farinose soredia, 0.02-0.03 mm diam., yellow-greenish, that extend to the whole thallus as a continuous leprose mat, more or less thick and cracked. Apothecia very rare, 0.5-1 mm diam., convex, disc brown-pink, exciple absent. Ascopores ellipsoid, 3-septate, 9-12 x 2-4 µm. Photobiont: chlorococcoid. C-, K-, KC-, Pd-, UV + yellow-orange. Uncommon (or understated), on bark or wood of old trees in humid woodlands and, in our prospection area, mainly at the basis of north face of Pinus near the seashore. See Chrysothrix candelaris (sometimes associated), bright yellow, Lecanora expallens (C+ orange) and Chrysothrix chrysophtalma (fertile and without soredia).