Description: Thallus fruticose, attached with a basal holdfast, shrubby to subpendulous, up to 8(-10) cm long, irregularly branched, grooved and weakly ridged between grooves, pale greyish green to yellowish green on all sides. Branches with diffuse, granular to subcylindrical, finally sorediate isidia originating from cracks along the ridges. Medulla white, dense. Apothecia rare, lecanorine, to 6 mm across, with a brown disc and a wrinkled thalline margin. Asci 8-spored, clavate, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, 8-9 x 5-6 µm. Pycnidia terminal on short lateral branches. Photobiont chlorococcoid. Spot tests: cortex K-, C-, KC+ yellowish, P-; medulla K-, C-, KC-, P-. Chemistry: cortex with usnic acid; medulla with divaricatic acid.
Note: a boreal-montane, circumpolar lichen found on bark (often on twigs) of conifers, sometimes on lignum (e.g. on wooden poles, decorticated branches), with optimum in the subalpine belt; most common in the Alps, but also found in the southern Apennines (Mt. Pollino).
Growth form: Fruticose
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)