Ark. Bot. 30A, 11: 13 (1943).
Basionym: Parmelia subsimilis H. Magn., Ark. Bot. 30B, 3: 5 (1942).
Protolog: Data lacking.
Protolog type data: Data lacking.
Type locality: Hawaii, Kauai, Lehua Makanoe [Lihue Makahuena], on Wikstroemia, 15.3.1938, L. M. Cranwell, O. Selling & C. Skottsberg 6034 (UPS - isotype).
Type locality coordinates: Data lacking.
Molecular barcode: Data lacking.
Thallus: foliose, often forming rosettes, to c. 10 cm diam., closely adnate. Lobes to c. 2.5 mm wide, hollow, with rounded tips, indented, branched, radiating. Upper surface grey or greenish grey, usually darker along the margins, smooth, shiny and perforate; perforations rounded-elongated, mostly < 0.5 mm diam.; soralia in the lobe tips, labriform, lacerate, fiinnel-shaped with flange-like margins, early with a central opening into the medullary cavity. Lower surface black, wrinkled, without rhizinles. Apothecia not known in the Nordic countries, sessile, margin ? sorediate. Pycnidia infrequent. Conidia c. 5 x 1 μm.
Photobiont: Data lacking.
Chemistry: Cortex C-, K+ yellow, KC-, PD-; atranorin. Medulla C- K+ yellow, KC-, PD+ yellow orange; stictic, constictic, menegazziaic and ? norstictic acids.
Ecology: Corticolous, most common on acid bark as Betula and Alnus but also on Fraxinus and Sorbus, occasionally saxicolous, on shaded, vertical rocks.
Distribution Type: Widespread in temperate and montane areas including Oceania, Asia, North and South America and the Caribbean. Rare but locally common in southwestern Norway. Suboceanic, in Europe occurring along the Atlantic coast and in the Alps.
Note: Bjerke (2003: 393) cites the years of publications as "Ark. Bot. 30A, 11: 13 (1942)" and "Ark. Bot. 30B, 3: 5 (1941)".
The type is currently unavailable, see Bjerke (2003: 394).