Thanks to ðJ - we have a link to the Specimen Image at the Smithsonian
And thanks for the suggestion that I should set up the project - everything (well not everything yet) is coming together. I have identified three similar specimens so far.
AND added a tag so they may be viewed without too much effort - remembering that these may not be correct [Xanthoparmelia Fig16]
NOTE the first observation looks slightly paler but this may have been due to time of day.