A rare lichen last seen in Edinburgh in 1797 has made its reappearance in the Garden at Inverleith. RBGE's resident lichenologists Brian Coppins and Chris Ellis were examining the lichens growing on deciduous rhododendrons in the Azalea lawn when they discovered the gristle lichen, Ramalina fraxinea, attached to a rhododendron stem.
The gristle lichen has declined, sometimes to local extinction, in many parts of Britain due to high levels of sulphur dioxide air pollution prevailing since the Industrial Revolution. It is thought that rigorous and effective measures to reduce air pollution in the last decades have allowed lichens such as this to return to areas where they had previously died off.
The specimen found consisted of several rigid, strap-like lobes, the largest being 8cm long. Under ideal conditions, such as parkland trees in the north east of Scotland, this lichen can attain an impressive length of 30cm.