Caloplaca xantholyta (Nyl.) Jatta
Leproplaca xantholyta (Nyl.) Hue
Thallus leprose, surface powdery or minutely granulose (under magnifying lens), margin sometimes lobulate, yellow, bright yellow to lemon yellow, tinged greenish in shaded areas, typically showing white medulla in thallus eroded sections. Apothecia unknown. Photobiont: chlorococcoid. Thallus: C-, K+ purple, Pd-. Rare in our prospection area, on vertical shaded walls of calcareous or more or less neutral rocks. See Caloplaca chrysodeta of which the thallus is also leprose, but brown-yellow or golden yellow without white sections and with un-lobulate margin.