Common on horizontal branches of broad leaved trees in moist habitats. It forms small circular patches of bright-green to olive-brown warted and often sorediate granules. Flat, brownish black apothecia, about 1 mm diameter

Determiner: 
Brian Coppins

References: 
Smith et al. editors (2009) The Lichens of Great Britain and Ireland
Dobson (2018) Lichens: an Illustrated Guide to the British and Irish Species