Thallus: crustose, up to 2.5 cm broad, continuous to discontinuous; areoles scattered to clustered, verruculose or sometimes cracked, mostly convex to strongly convex, occasionally plane, 0.1 - 0.6 - 0.9 mm wide, 0.10 - 0.25 - 0.5 mm thick; cortex indistinctly paraplectenchymatous; margin indistinct, of scattered areoles or fading, or distinct, sometimes minutely lobate. Colour yellow or rarely with orange tinge, never orange, not pruinose. Prothallus sometimes present, yellow to greyish, thin and often spot-like. Apothecia mostly present and abundant, scattered to aggregate, zeorine, sessile when young but soon raised, 0.3 - 0.8 - 1.1 mm, round to irregular. Disc mostly + plane, deep yellow to orange yellow. Proper margin rather thin, 25 - 40 - 80 µm, mostly somewhat raised above disc, lighter than disc, consisting of irregular to radiating, thick-walled hyphae with elongate, 5 - 16 µm long cells that towards the rim become shorter and almost isodiametric, c. 4 µm wide. Thalline margin mostly present but rather thin, up to 75 µm, even to crenulate. Hymenium 65 - 85 µm thick, hyaline. Hypothecium 40 - 70 µm thick, hyaline. Paraphyses simple to occasionally sparsely branched above, 1.5 - 2.5 µm wide, tips capitate, 3 - 7 µm wide. Asci with eight spores, or sometimes less. Spores polaribilocular, ellipsoid, 10.0 - 11.6 - 16.8 / 4.5 - 6.0 - 8.5 µm, septum 3.5 - 4 - 6.5 µm. Pycnidia mostly present, immersed, pale orange. Conidia narrowly ellipsoid, 2.5 - 4.5 / 1.2 - 1.5 µm (based on Arup 1997: 505).

Photobiont: Data lacking.

Chemistry: Parietin (main substance), emodin (minor), parietinic acid (minor), teloschistin (minor), fallacinal (minor). Thallus and apothecia K+ red, C-, PD-, I-. Group A according to Santesson (1970), group 1 according to Arup (1995) (Arup 1997: 505).

Ecology: On seashore rocks in the supralittoral zone (Stephenson & Stephenson 1949) as well as above the littoral zone and in maritime sites up to some kilometres inland. Found on a wide range of rock types, from hard siliceous rocks to limestone, mortar, and concrete. Also on wood (Arup 1997: 505).