I can't make out any pink sclerotia, but is Marchandiomyces corallinus likely to be the cause of this assault?
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Some fungi are very poisonous so a mistaken ID could have serious consequences.
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As I have said, I am going to put up a picture of mite damage on my site sometime (not sure when, enmeshed in Hypotrachyana just now). The damage is bright orange.
Now whether the pigment is produced by the lichen as a result of such damage, or whether the mites are feeding on parts of the lichen infected by the fungus, I am not sure. Your photo 2 certainly looks like the spreading infection of a pathogen.
My own practice is NOT to record Marchandiomyces (and bearing in mind there are two species anyway) unless I see the sclerotia. This is in line with my practice with microfungi on higher plants, when I do not accept lesions as proof of a particular fungus. Ellis & Ellis have nice descriptions of microfungi on plants, including their characteristic leaf-spotting patterns, but too often the microscope disproves the expected identity. I think the same approach should apply to orange patches on Parmelia - yes, very likely Marchandiomyces corallinus, but best not to record it without seeing the fungus itself. My own view.
Sounds very reasonable to me, and good advice for the day when I trust my lichen ID skills enough to submit records.
Lat/Lng: 53.6745274, -2.510697
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