Lecanora hybocarpa the Answers

Anthony

Yes L. sinuosa s. lat. would also make sense, I will leave that decision to Brian Coppins.

I suppose the confirmed presence of L. pseudoargentata in Europe complicates matters a bit.

That was for another post but a slightly distinct Lecanora chlarotera s. str. like taxon from the New Forest, with a chlarotera-type epihymenium, dark brown disks, often slightly pruinose and found on horizontal branches in sheltered glades in the New Forest pasture woodlands may be L. pseudoargentata. A ITS sequence has returned a match for what I was told over the phone was L. pseudargentata, which at the time did not make sense. Now it does, but I need to double check I remembered right! If that is it, it is never going to be mistaken for L. sinuosa s. lat./Lecanora hybocarpa s. lat.

Neil

OK this is the sequenced specimen of Lecanora pseudargentata:

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Specimen, from Oak twig on low on Oak in glade in Beech – Oak old growth pasture woodland

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Closer view of older and younger apothecia

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High magnification view of disks with pruina

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Apothecia cross-section in polarised light

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Epihymenium with a darker brown pigment and granuals

Neil

Been working over the weekend on herbarium specimens and in the field on Lecanora pseudargentata. It seems to be widespread if local on the New Forest, so to be looked for elsewhere. One interesting development is I had noticed some UV+ fluorescence from the pruina on the disks previously and looked into this. This has been confirmed and seems very useful. The pruina (presumably actually the epihymenium crystals), fluoresce a distinct grey-blue:

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Lecanora pseudargentata, on Beech twig on glade edge, Stubbs Wood, New Forest.

There is also a week but distinct UV+ orange-brown fluorescence from the thallus, strongest on the margin (likely from gangaleoidin; see Lecanora gangaleoides), but this is much less obvious.The disk UV fluorescence was strongest on disks with well developed pruina, but usefully was also visible on disks with little or no visible pruina and also chewed up and poorly developed thalli; so very useful. From other specimens the disk UV fluorescence is absent in Lecanora argentata (not surprising, as it has no crystals) and Lecanora chlarotera s. str. Some Lecanora hybocarpa s. lat. specimens occasionally had a hint of this fluorescence but it was weaker and it was not always visible. The fluorescence is particularly good in separating Lecanora argentata from Lecanora pseudargentata, which is the only other Lecanora which would typically have dark chestnut brown disks. None of the others showed distinct UV+ orange-brown fluorescence from the thallus

As Lecanora argentata also has gangaleoidin, so I also scanned my specimens of this species for gangaleoidin fluorescence. Yes there actually is some on the thalline margins but it is much weaker that in Lecanora pseudargentata and would not be field visible. Occasionally it was stronger in the medulla in cut specimen edges or on damaged thalline margins. One specimen was different, however, this had noticeable UV+ grey-blue fluorescence on the disk, but not as strong as some specimens, and the thallus was also distinctly UV+ orange-brown, especially on the thalline margins. I then checked an apothecia cross section and yes there was a thin and patchy crystal layer above the paraphyses tips I had missed before: so also Lecanora pseudargentata. This was from a parkland Oak in Ethy Park, East Cornwall, collected in 2013.

Also just for interest a Lecanora chlarotera s. str. collected from an Oak branch with Lecanora pseudargentata this weekend:

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Lecanora chlarotera s. str., Oak Branch, on edge of pasture woodland Rans Woods by wet grassland. The glow below the epithecium is reflection from the asci or the paraphysis not from crystals.

Neil