Picture taken at Querigut, Ariege, France, Oriental Pyrenees, on granite, among mosses.
Granulous thallus, yellow. Scattered tiny granules, on a black prothallus. The name comes from the colour yellow egg ("jaune d'oeuf") of the apothecia´s discs. Apothecia thalline margin paler than the disc becoming crenulate.
K-. It helps to separate it from the Caloplaca citrina group species.
? Doubt due to the clusters of granules, because they are normally more scattered. For the rest it fits with the type.