[AlanFUSA]

Hi Jenny:

I didn’t want to say too much in my previous post because I wanted to check some collections. We have an undescribed species from southern Sweden that is close to L. erythrophaea but has smaller spores (10–12 × 4–5 µm), which is more or less the same as those of your collection. The Swedish collections are all on Fraxinus and the young apothecia have a distinct proper margin so I can’t say for certain that your collection is that species, but it certainly appears to be close.

Please hang on to your collection because we may want to sequence it – and if you can find more, that would be even better.

Alan

[AlanFUSA]

I also wondered if the spores were truly muriform. I think Mark is on the right track here. If it is an Aspicilia the epihymenium will become bright green in nitric acid.

[AlanFUSA]

Can I just throw Lecidea erythrophaea into the mix. I think of that species as resembling Catillaria (lax paraphyses with a distiinct pigmented cap) but with a different ascus structure, and that fits the photos of this collection. The ascus appears to be Bacidia-type (penultimate photo), which is the same as erythrophaea but not J. tavaresiana (Lecidella-type). We still have the small spore problem ((8–) 9–14 (–18) × 3–4.5 (–5) µm in L. erythrophaea) but at least the spore width fits.

Alan

[AlanFUSA]

I’m still not convinced. I could tlc it here – or Becky might be able to do it at E (or even sequence it).

[AlanFUSA]

Of those two, I would go with P. contraponenda (semi-immersed apothecia), but I still think P. zeoroides is an option.

Below is the illustration of Porpidia exciples from Gowan (1989): P. rugosa is albocaerulescens-group (9). P. contraponenda/irrigua is cinereoatra-group (14), P. zeoroides is P. macrocarpa-group (11-13).

Unfortunately, spot-test are unlikely to of any use – although P. zeoroides sometimes has sticitc acid, so K+ yellow would be conclusive, but K– would prove nothing. You really need tlc (or DNA),

Measuring the width of exciple medulla is difficult. The best way I have found is to decolourise the section with C and counter-stain with Phloxine-B, but even then you need a good microscope and oil-immersion to have any chance. Just partially decolourising with C also works sometimes.

Alan

[AlanFUSA]

Interesting… Not P. rugosa – the exciple medulla is completely hyaline in that species. The macroscopic photo looks like contraponenda/irrigua, but I don’t think it’s that either, because that group has a more uniformly dark exciple. This looks more like a macrocarpa-group exciple, but I’m struggling to suggest a species.

Where is the pruina located on the apothecial margin? Some of the apothecia appear to have an almost completely white pruinose excipe. If the pruina is on the outside of the margin it could be P. zeoroides, which would be a nice find!

Alan

[AlanFUSA]

Not all species are lichenicolous – some species occur on liverworts. The green spores are immature.

[AlanFUSA]

Looks like a Sclerococcum sp. to me -Alan

[AlanFUSA]

Try Luca Borgato <luca.borgato@skynet.be>

Borgato, L., Fryday, A. M. & Ertz, D. 2020. Preliminary checklist of the lichens and lichenicolous fungi of Martinique, with 144 new records. – Herzogia 33: 139 –178.

[AlanFUSA]

Vezdaea leprosa?

[AlanFUSA]

Jonas:

Any reaction with K?

Alan

[AlanFUSA]

Maxine recently found something similar – see the post Possible commensal association between a cyanobacterium and Lecidella elaeochroma on this forum earlier this year. We also briefly discussed similar structures in our recent paper describing the new genus Gilbertaria <https://link.springer.com/article/10.1007/s11557-022-01838-5> open-access), although in both these cases the “photobiont” is a green alga. Are you sure this is not what you have here?

Alan

[AlanFUSA]

Hi:

Impossible to say for certain, but I suspect the orange ones are a Porpidia sp. (possibly P. crustulata) and the grey ones Rhizocarpon reductum. Close up photos are needed for a more positive ID, but even then identifying crustose lichens from macro photos is near impossible because microscopic characters are usually required.

Alan

[AlanFUSA]

Mark is correct. The distinction between T. coarctata and T. elacista are subtle, and I went for T. elacista solely on the presence of the crack between thallus and apothecia. The T. coarctata map should really be renamed T. coarctata s. lat. as all pre-2028 collections of T. elacista would have been called T. coarctata.

Also agree about your ascus staining. The Trapelia-type ascus is described as “tholus I–, with I+ blue flanks, which is exactly what you photo shows!

The C– reaction is puzzling. I always check for C+ reaction under a compound scope, so you should try that, but without tlc there’s not much more to be done – except to note on the packet that it is C–.

Cheers – Alan

[AlanFUSA]

Porpidia flavocruenta looks OK. It is much more frequent in the UK than P. favicunda. I’ll pass on the ?Endococcus.

Alan

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