J. Hattori Bot. Lab., 76: 205, 1994.. Basionym: Pannaria confusa P.M. Jørg. - Ann. Bot. Fenn. 28, 1: 87, 1991.
Distribution: N - TAA (Nascimbene & al. 2021, 2022).
Description: Thallus squamulose, heteromerous, episubstratic, 100-150 µm thick, blue-grey to olive-brown, of 1-2 mm wide, rounded or slightly elongate, contiguous or imbricate, sorediate squamules with a white-felted, upturned margin, developing on a thin, often inconspicuous, blue-black hypothallus, usually forming a thick, cracked crust. Soredia granular, blue-grey, arranged in marginal, sometimes finally confluent, soralia which do not tend to become woolly in the herbarium. Upper cortex sclerenchymatous, 25-40 µm thick, of thick-walled cells. Apothecia very rare, lecanorine, up to 1 mm acrosss, with a concave, brown disc and a sorediate thalline margin. Proper exciple subparaplectenchymatous; epithecium pale brown; hymenium colourless, I+ blue-green turning reddish; paraphyses simple, coherent, slightly swollen at apex; hypothecium colourless. Asci 8-spored, subcylindrical to clavate, with a I+ blue tholus and an internal, more intensely I+ blue structure. Ascospores 1-celled, hyaline, ellipsoid, with a thick epispore and broadly attenuated apices, 12-15 x 5-8 µm without epispore, 17-23 x 8-9 µm with epispore. Photobiont cyanobacterial (Nostoc, the cells in clusters). Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: terpenoids and aliphatic acids.
Note: a rare European species with a boreal to temperate-high montane distribution, found on branches of various trees and shrubs near the ground, but also on rocks in very humid places, like in the spray zone of waterfalls; known from a few localities in the Alps.