‘Lepraria ecorticata’ on Bark is Andreiomyces obtusaticus

I now have my specimens back from Alan Orange (see end of this thread https://www.fungi.org.uk/viewtopic.php?t=3252” class=”bbcode_url”>https://www.fungi.org.uk/viewtopic.php?t=3252). Another problem he solved as well as Micarea subviridescens, was the pale yellow-green Lepraria like lichen found deep in cervices on dry bark on older mature and veteran Oaks. This had been previously identified as “Lepraria ecorticata“, but it has long been known not to be this. Alan kindly looked at a specimen with TLC and sequencing and proved it to be Andreiomyces obtusaticus, a little known species that he had recorded once before on a Hazel in Dorset.

[attachment=0]2021-12-29 Andreiomyces obtusaticus.jpg[/attachment]
Andreiomyces obtusaticus, collected from deep in an crevice in dry bark on an older Oak in the New Forest. Growing with Lecanactis abietina, a typical associated species.

The loose Lepraria like thallus with the very distinct colour and a lack of spot tests (only K+ brownish possibly on this specimen) is reasonably distinctive. Lecanora expallens occurs in the same habitat, but is more yellow, sorediate rather that leprose and should be C+ orange and we also have the new K/UV+ lime green test for arthothelin, if the C reaction in Lecanora expallens is week.

Neil