Op. Bot. 42: 140 (1977).
Basionym: Imbricaria lanata var. minuscula Arnold, Verh. Zool.-Bot. Ges. Wien 28: 293 (1878).
in IF nur (Arnold) Brodo & D. Hawksw.
Thallus: prostrate and decumbent, sometimes subcrustose in central parts, closely attached to the substratum, rosettes usually not exceeding 3 cm diam., dark brown to black, mostly shiny. Branching isotomic dichotomous, internodes distance 0.2- 0.5(-1) mm, branches mainly uneven and knobby due to pycnidia, terete, 0.2- 0.5 mm diam. but flattened at apices and to 1 mm wide, in central parts thinner and with numerous side branches. Apothecia rather common, to 3 mm diam., margins smooth to verrucose; disc dark brown. Spores ellipsoid, 8-10 x 5- 7 μm. Pycnidia common. Conidia slightly dumbbell-shaped, 6- 8 x 1- 2 μm.
Photobiont: Data lacking.
Chemistry: No secondary substances (by TLC).
Ecology: Siliceous rocks and stones in open areas, often alpine or arctic heaths or along sea and lake shores.
Distribution type: Mainly in the alpine and arctic areas, but scattered south to Denmark. Circumpolar arctic-alpine, extending to boreal zone in Europe, Asia, Australasia, North America, South America, Antarctic.
Taxonomy: Data lacking.
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