Latin name: Caloplaca luteoalba
This very rare crustiose lichen previously occurred on the bark of veteran English and Wych Elms, often alongside Bacidia incompta (another rare lichen). It has also been recorded on limestone rock and lime mortar. The British Lichen Society has old records from the Arkengarthdale and lower Swaledale in the far North east of the Yorkshire Dales National Park. The National Park Authority is planning a carefully targeted specialist survey of rare lichens on veteran trees with the aim of finding out its current status.
The national population of this lichen declined due to the loss of Elms associated with the Dutch Elm disease in the 1970s. It is now a UK and local priority species for biodiversity action.