Light Crottle - lichen - Ochrolechia tartarea - once used for dyeing.

As more info is found, names of lichens are often changed or modified.
Ochrolechia tartarea can be found in old records and museum herbarium collections, listed as Lecanora tartarea.

Used as a dye in the UK (red/purple), aparently collected in May - June then soaked in urine for weeks before being dried  in 'cakes' in peat smoke to dry.   

It was also used as a dye in Sweden.

Light crottle - Ochrolechia tartarea.
Growing on Dunnet Head and samples from Manchester Museum Herbarium.

The house dress was often worn by women when dyeing yarns with lichen (crottle /crotal) in the Scottish Highlands & Islands.
Traditionally the house dress had small repeat floral patterns.
I'm drawing crottle for a new housedress pattern.