Parmeliaceae Melanohalea exasperatula Growth type foliose Chemical reactions negative Occasional on branches and trunks of nutrient-rich wayside trees, also on rocks and walls. Olive-green or brown-green thallus, often with wavy, raised marginal lobes. The hollow, inflated isidia are very dense at centre of thallus and develop into divided lobules. Lobes pale brown beneath with scattered rhizines. Pycnidia absent, apothecia rare. Similar: M. elegantula, solid isidia. Melanelixia glabratula, medulla C+ red

Melanohalea exasperatula
On Oak. Holton Lee, Dorset. December 2012