Physciaceae Physcia dubia Growth type foliose Chemical results: Cortex K+ yellow, medulla K- Found on nutrient-enriched siliceous rocks, walls and bricks. Greyish thallus, the narrow, radiating lobes with terminal, lip-shaped soralia. Marginal cilia absent. Similar: Physcia caesia. Basic substrates, cortex and medulla K+ yellow. Physcia tenella has marginal cilia

Physcia dubia
Sturminster Marshall, Dorset. March 2014