A crustose lichen with a mustard-yellow to brownish thallus that consists of largish granules that are irregular in shape, and sometimes somewhat flattened. The granules clump together to form a thick, coarsely cracked crust with a distinctive upper surface that resembles the top of a cauliflower. The apothecia are dirty yellow and may have crenulate margins.
Candelariella vitellina f. vitellina can be found throughout Scotland on nutrient-enriched siliceous and calcareous rocks, especially those used by birds as perches. BLS distribution map
Candelariella vitellina f. vitellina is distinguished from Candelariella aurella f. aurella on basis of the granules being clumped into a thick crust rather than thinly scattered onto a distinctive black prothallus.
scottishlichens.co.uk 