Foliose macrolichen.

Very common in Southern and Central Finland, often the most abundant epiphytic macrolichen species, sparse only in northernmost Lapland.

3–8 cm.

Lobes rather narrow (1–5 mm), tubular and hollow, lobe tips ascending. Upper surface light gray to gray or with brown tint. Underside black, without rhizoids, fastened to the substrate with little differentiated attachment site. Lobes often with terminal soralia.

Ascoma

Apothecia rare, on upper surface, sitting up with narrowed base, flat to concave, with thalloid margin. Hymenium brown.

Ascospores one-celled, hyaline.

Green alga (Trebouxia).

In all types of forests, relatively resistant to atmospheric pollution.

Predominately epiphytic, on acid bark of conifers and deciduous trees, also on snags and coarse woody debris, and on silicate rock surfaces, sometimes even on soil.