Species: Physcia caesia
Photos: On rocks and wooden bench. Co. Cork, SW Ireland.
Adpressed, orbicular, pale bluish-grey thallus, convex lobes with small pseudocyphellae. Underside white to tan with scattered rhizines. Abundant farinose or globular soralia with bluish-grey flecks. Black, pruinose apothecia with prominent margins.
Usually occurs on nutrient-rich rocks, tombstones, cement and asphalt. Also found on basic-barked trees.
Cortex and medulla: K+ yellow
Physcia caesia. December 2008 and May 2012