Description: Thallus fruticose, tufted or decumbent, 3-7(-12) cm long, bicolorous, the basal parts brownish black to black, the apical parts pale brown to brown, usually shiny, isotomic-dichotomously branching, with coarse and distinct, c. 1 mm thick, terete or basally slightly compressed, shallowly foveolate main branches, and short lateral spinules arising at right angles to main stem. Soralia fissural, concave to plane, white, with isidioid spinules and farinose soredia. Pseudocyphellae absent or inconspicuous; medulla white, compact. Apothecia unknown. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-. Chemistry: no lichen substances.
Note: a temperate species found on large, more or less shaded rock walls, more rarely on bark, especially on twigs of conifers in damp montane forests.
Growth form: Fruticose filamentous
Substrata: bark and rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)