Österreich. Bot. Zeitschr. 9: 8 (1904).
Protolog: Data lacking.
Protolog type data: Gran Canaria: Tafira 400 m corticola ad ramos emortuos Pelargonii.
Type locality: Spain, Canary Islands, Gran Canaria, Tafira, on twigs of dead Pelargonia, 400 m, Bornmüller, Pl. Canar.: 3500 (W- isotype). [TLC: divaricatic acid].
Type locality coordinates: Data lacking.
Molecular barcode: Data lacking.
Thallus: fruticose, 1 - 3 - (6) cm high, with one to few palmately or irregularly branched laciniae from a narrow holdfast, occasionally with short, divergent secondary branches from the lobe margins. Laciniae 1 - 3 - 5 mm broad, stramineous or pale grey-green, more or less longituinally ridged from raised chondroid strands near the base, uneven and pitted distally, pseudcyphellae indistinct or absent. Soralia parietal, the green soredia erupting through marginal and laminal cracks, sometimes leading to separation of upper and lower tissue layers and thereby giving a false impression of a fistulose thallus. Cortex 10 - 20 µm thick, chondroid cylinder mainly continuous, medulla lax, with groups of algal cells and individual soredia throughout. Pycnidia not seen. Apothecia rare, subapical, mature spores not seen (Krog & Østhagen 1980: 265).
Photobiont: Data lacking.
Chemistry: Divaricatic acid (Krog & Østhagen 1980: 265). Usnic acid in the cortex.
Ecology: Corticolous. Seems to prefer well lit sites with a certain influence of mist. In the Canaries between 400 and 1000 m altitude.
Distribution Type: Mediterranean and Canary Islands: Hierro, La Palma, Gomera, Tenerife, Gran Canaria, Lanzarote.
Note: A variable species, ranging from a single palmate lobe to a dense, eroded, ragged cluster of lacerate-contorted branches. Soredia are often in subterminal, inflated vesicles. Eroded specimens, especially when on rocks, can resemble R. lacera which lacks a cartilaginous subcortex, has soredia on the surface and a different chemistry (Smith et al. 2009: 783).