The descriptive text, below the map, is from the Cornish Red Data Book (2009). The map on this web page depicts the organisms distribution and shows the records made pre-2000 and those made since.
Range & Status
A crustose species which has a wide overall distribution in Britain, but is currently known in England from only a few sites, south Somerset and two sites in Cornwall: on Ash Fraxinus excelsior twigs near Mawnan Smith and also on Ash in East Cornwall. It has not been found in its former localities elsewhere in southern England or in North-east Yorkshire. In Scotland it is known from five localities and has recently been discovered in Ireland, in County Fermanagh. It is mainly a boreal species growing on more or less smooth bark of deciduous species, especially Ash but also Aspen Populus tremula and Hazel Corylus avellana , in sheltered woodland.
I.J. Bennallick, S. Board, C.N. French, P.A. Gainey, C. Neil, R. Parslow, A. Spalding and P.E. Tompsett. eds. 2009. Red Data Book for Cornwall and the Isles of Scilly. 2nd Edition.Croceago Press.
The Cornish Red Data Book Project was led by the Cornwall and Isles of Scilly Federation for Biological Recorders (CISFBR). The full text and species accounts (minus the maps) are available on the CISFBR website.