Mycol. Res. 108, 8: 882 (2004).
Basionym: Parmelia exasperatula Nyl., Flora, Regensburg 56, 19: 299 (1873).
Description: Lichen. Thallus foliose, appressed or slightly raised at margins, to 5 cm diam. Lobes short, broadly rounded, to 5 mm wide, contiguous to somewhat imbricate. Upper surface pale to dark olive brown, shiny, sometimes with a faint pruina in central pans, smooth or a slightly wrinkled and pitted; without pseudocyphellae and soredia; isdia common, in?ated and clavate to spathulate, hollow, originating from cylindrical papillae. Lower surface pale brown, darker in central parts, with concolorous rhizines. Apothecia rare, sessile, margins smooth to crenulated, to 3 mm diam. Spores 8-11 x 5- 8 μm. Pycnidia not observed.
Photobiont: Data lacking.
Chemistry: No lichen substances (by TLC).
Ecology: Preferably corticolous on deciduous trees. In the northern part of its Nordic distribution range now and then also on conifers, on lignum, or saxicolous on so? rocks.
Distribution type: Widely distributed in the Nordic countries up to the Arctic Circle. Most common in the south. Known from most parts of Europe and North America. Probably circumpolar but rare or poorly known in Asia.
Taxonomy: Data lacking.
Note:
Distribution Database: Distributions
Distribution Database: Discover Life
Picture Database: Tropical Lichens
Molecular Database: Genbank
Synonym Database: Index Fungorum
Synonym Database: Mycobank