Vainio, E. (1909). Lichenes in viciniis stationis hibernae expeditionis Vegae prope pagum Pitlekai in Sibiria septentrionali a Dre. E. Almquist collecti. Praefationem scripsit F. Almquist. Arkiv for Botanik, Band 8, No. 4: 11-175.
Thallus tightly adnate, radiate-laciniate and effigurate, laciniae 0.3(-0.5) millim. wide, well convex and thick, solid, yellow-orange, opaque, isidia and soredia and pruina absent, upper surface not rimulose, medulla closely woven together. Thallus opaque, somewhat to largely thicker than Pl. lucent Nyl. (Wain., Exp. Antarct. Belge Lichen., 1903, p. 23) and more completely colored and transparent than Pl. australi (Arn.) Wain. (whereas and also spores distinguish it from Placodium murorum). P. etesia (Nyl.) Wain. It is similar to this species in the size of the lacinia and the closely pressed together medulla layer, but it departs in the egg yolk yellow colour of the thallus.