Physciaceae Physcia tribacia Growth type foliose Chemical results: Cortex K+ yellow, medulla K- Found on sheltered, nutrient-rich bark and on +/- vertical walls and rocks. Most frequent in southern Britain. Light greyish overlapping lobes with ascending tips, faintly pruinose, pseudocyphellae absent. Lobe margins with granular soredia. Apothecia very rare. Underside whitish, cilia absent, rhizines sparse. Similar: Physcia tribacioides. Cortex and medulla K+ yellow

Physcia tribacia
On old Ash. Upton Park, Dorset. January 2013