Protolog type data: British Isles, England, V. C. 1, West Cornwall, Scilly Isles, Bryher Island, narrow peninsula between Rushy Bay and Stony Porth. Sheltered seashore granite rocks, on both horizontal and vertical surfaces, elev. 4 m, Arup L92121 (LD-holotypus, BM, MIN-isotypi).

Type locality: United Kingdom, Great Britain, England, V. C. 1, West Cornwall, Scilly Isles, Bryher Island, narrow peninsula between Rushy Bay and Stony Porth, sheltered seashore granite rocks, on both horizontal and vertical surfaces, 4 m, s.d., U. Arup L92121 (LD - holotype; BM, MIN-isotypes).

Type locality coordinates: Data lacking.

Molecular barcode: Available.

Thallus: 0.2-1-2 cm diameter, composed of scattered to contiguous areoles, that occasionally form small, verruculose cushions; margin usually thin and indistinct but occasionally with up to 0.2 / 0.1 mm large lobes; areoles convex and often with an incised base or forming minute squamules, 0.1-0.4-0.5 mm across, 0.1-0.25 mm thick, up to 0.8 mm when forming cushions, pale yellow to orange-yellow, sometimes grey, with an even surface, usually soon covered by soredia; soralia punctiform, 0.1-0.35-0.5 mm, round to somewhat irregular, one on top of each areole, often covering most of the areoles, slightly concave to slightly convex, intense yellow to yellowish orange, usually more intense than thallus; soredia fine, without protruding hyphae, 20-26-30-40 µm (n=6), occasionally as consoredia or blastidia-like, up to 50 µm diameter. Prothallus absent. Apothecia unknown. Pycnidia unknown (Arup 2006: 499).

Photobiont: Green alga.

Chemistry: Parietin (major), small amounts of fallacinal, emodin, teloschistin, parietinic acid corresponding to chemosyndrome A of Søchting 1977 (Arup 2006: 501).

Ecology: "Caloplaca sorediella grows both on seashore rocks of various kinds, for example hard silicious rocks, sandstone and volcanic rocks, and plant debris or on the base of plants, e.g. Armeria or Spergularia. When growing on rocks it was found on steep surfaces, usually exposed or very exposed, but also more sheltered. All collections [of the author] were made in the mesic supralittoral zone or just above it, but in one locality in Scotland (W. Sutherland, Assynt, Achmelvich) it seems to occur a short distance away from the shore. In one maritime locality the steep cliffs were manured by birds, but C. sorediella does not seem to benefit from it. ... In extreme maritime sites. It is likely that C. sorediella is a true marine or maritime species, but it should also be looked for elsewhere in western Europe (Arup 2006: 499, Arup 2006: 501).

Molecular data: Genbank

Distribution: Western England, Scotland and Wales, e.g. Lands End, the Scilly Isles, Bardsey Island and Skomer Island. North American specimens probably belong to C. citrina s. str. or a similar species (Arup 1993).

Note: Molecular analyses carried out on the C. citrina group showed that C. sorediella does not belong to this group and nor does it belong to the large Xanthoria clade to which the C. citrina group belongs (Arup 2006, Arup 2006: 501).