Order: Lecanorales       Family: Parmeliaceae Species: Melanohalea exasperatula Growth type foliose. Photos: On Prunus. Dunmanway, Co. Cork, SW Ireland. Identified by John Douglasand Brian Coppins Thallus olive-green to brownish-green, adpressed at centre but often with wavy, raised marginal lobes. Lower surface pale brownish with scattered pale rhizines. Decumbent isidia are rounded, hollow and inflated, very dense at centre of thallus, developing into divided lobules. Apothecia are very rare, pycnidia absent. Occasional on branches and trunks of nutrient-rich wayside trees, also on rocks and walls. Chemical reactions negative. Similar: Melanelixia glabratula. Medulla C+ red

Melanohalea exasperatula. January and February 2010