Order: Teloschistales       Family: Teloschistaceae Species: Polycauliona polycarpa (Xanthoria polycarpa) Growth type foliose Photos: On urban trees. Dublin and Macroom, Ireland. Thallus forms small rosettes of orange-yellow to greyish-yellow crenulate lobes with finely divided apices. Abundant apothecia, often completely covering the thallus. Orange-brown discs become contorted, margin sometimes excluded. Isidia and soredia absent. Ascus 8-spored, spores colourless, polarilocular, 11-15 x 6-8 µm. Microscope photographs below. Occurs in urban and rural areas on nutrient-rich or high PH bark in angles of twigs, often on Elder. K+ crimson / purple. Can be confused with immature Xanthoria parientina.

Microscope photographs



Polycauliona polycarpa (Xanthoria polycarpa)