[Mark Powell]

Hi Juliet,

The host would make Opegrapha hochstetteri ined. more likely (Thelidium decipiens being probably closely related to Verrucaria hochstetteri). The draft lichenic. key doesn’t have a couplet which includes O. hochstetteri (this species is just treated with a brief footnote). The couplet which would separate O. rupestris from O. hochstetteri (if it occurred in the key) suggests that it is only O. rupestris that has brown granules (in the perispore). I have just examined a specimen of O. hochstetteri and find that there are numerous brown granules in the vicinity of many of the ascospores. Whether or not these are actually within a perispore is difficult to ascertain but the granules often do seem to be contained in some gelatinous coating to some of the spores. Here are some micrographs of ascospores of O. hochstetteri.

There is some information about both O. hochstetteri and O. rupestris on FGBI website. Frustratingly, I couldn’t lay my hands on a specimen of O. rupestris to make a direct comparison, something that would be a very beneficial exercise.

I am not discounting the possibility of O. rupestris occurring on Thelidium decipiens but giving you the possibility of O. hochstetteri (which I find most commonly on Verrucaria muralis in my region). I think O. hochstetteri is yet undescribed.

Best wishes,

Mark

[Mark Powell]

I had the same reaction as Neil. The brown surface with cracks shows some superficial similarity to the upper surface of some Peltigera species but I think this is probably a non-lichenized fungus. I always carry a razor blade in the field and one of the uses for this is to check for any photobiont partner. In most lichens the algae or cyanobacteria can be detected by simple inspection of a cut or scratched surface under a hand lens. If a fresh-looking part of your mystery had been cut and examined with a lens, this would probably have helped settle the matter of whether lichenized or not. If it was a Peltigera there would be a blue-green coloured layer of cyanobacterial partner; if a non-lichenized fungus there would be no green or blue-green layer (except for degraded fungi which might become home to free-living algae).

Scratching the thallus of a lichen can help indicate which sort of photobiont is present – yellowish green indicates Trentepohlia, fresh green = ‘chlorococcoid’ green alga, blue-green = cyanobacteria.

These queries are always interesting, even if we can’t give a definite identification.

Mark

[Mark Powell]

Yes, I feel sure that you have the anamorph of the L. elaeochroma there. The pigment in the pycnidial wall is correct (blue-green) along with the thin, curved conidia. Here are some images of one of my specimens. In this case the pycnidium is not as immersed in the thallus as yours because mine was a young thallus just getting going. I do see pycnidia on L. elaeochroma quite often, though this is not mentioned in the Flora.

[Mark Powell]

I collected a bit of P. perlatum yesterday. I don’t observe a bright blue fluorescence of the medulla in my specimen using the Convoy S2. I do see an off-white reflectance that looks pale compared with the dull, mauve-brown of the cortex under UV. This reflectance is, if anything towards the yellow side of off-white rather than blue. It will certainly be interesting to compare specimens and observations at Cober.

I am not sure whether we are interpreting the same reflectance/fluorescence differently or whether there really is a difference between different specimens of P. perlatum. The latter would be an exciting prospect.

Best wishes,

Mark

[Mark Powell]

The ascospores of the fungus on X. mougeotii seem rather different in structure compared to ‘Pyrenidium actinellum’ on e.g. Caloplaca teicholyta. Those of ‘Pyrenidium actinellum’ remind me of those in Pyrenula with an unevenly thickened wall.

The first photograph shows the ascospores of the fungus on X. mougeotii.

Otherwise they are rather similar: perithecia with dark brown walls almost completely immersed in host, asci with a thickened apex, interascal filaments present (branched and anastomosed).

I have provided s a sketch of P. actinellum from C. teicholyta.

It is not very dramatic to look at under the lens except for the distinct bleaching of the host thallus. In one of the macro photographs an arrow indicates half an immersed perithecium which has been revealed by sectioning. Otherwise the perithecia appear as just black dots due to their apex protruding slightly.

This brief investigation has helped to enhance my impression that there may be several things with large brown, 3-septate ascospores which have been clumped under the name Pyrenidium actinellum.

Mark

[Mark Powell]

Hi Heather,

This is a coincidence because I am sure this is the same fungus that I found infecting X. mougeotii recently in a churchyard in Hertfordshire. I haven’t got around to studying it properly yet. The closest thing in the draft lichenic. keys seems to be Pyrenidium actinellum and this has been recorded from X. mougeotii. However, this fungus doesn’t seem identical to others which I record as P. actinellum on hosts such as Caloplaca teicholyta. I suspect that the name P. actinellum has been applied to various things with large brown, c. 3-septate ascospores.

Now that we have a potential second sighting of this thing, I will make the effort to produce a decent description of it and compare it with ‘P. actinellum’ from C. teicholyta.

Others might have different or contradictory comments to make but those are my provisional thoughts.

Mark

[Mark Powell]

Hi Juliet,

I agree with all your comments about these corticolous Caloplaca species.

C. pyracea does stand out as something different.

I check quite a few C. ‘cerinella’ specimens and find they ARE almost invariably C. cerinella.

I very occasionally come across 8-spored Caloplaca on smooth bark and my interpretation is that these belong to C. holocarpa s. str. I have recorded this on smooth poplar branches. I suspect that some or many records of C. cerinelloides are actually of corticolous C. holocarpa.

Mark

[Mark Powell]

I agree that it looks fine for C. pyracea. It has the definite grey thalline margin which then often becomes rather excluded as the apothecium matures. My decision is based much more on gross morphology than any microscopic characters.

It is turning up quite regularly in my part of the world, most commonly on aspen (twigs and small branches) but also sometimes on other trees. In Derbyshire, Brian, Steve and I were finding it on low-hanging Fraxinus branches. Perhaps one of the more surprising occurrences is on the trunk of a young Platanus tree in Exhibition Road near the Science Museum. I have also seen it on paint (which often develops a ‘twig’ community). LGBI2 (2009) mentioned it as a note within the description of C. holocarpa and at that time it was considered a rarity of Scottish aspen. I suspect two things have happened – that it has become more common but also that we now distinguish it from other Caloplaca spp.

In my opinion you could record this as the county first.

Mark

[Mark Powell]

I haven’t seen Phylloblastia cf. bielczykiae further north than Epping Forest. This is in contrast to the other two Phylloblastia species. I found P. fortuita in N.E. Yorkshire and P. inexpectata extends up into Scotland.

Just a note on filling in spreadsheets, I thought that we were discouraged from pasting things into the Taxon name column (L). For uncertain species I thought that Janet preferred the genus to be put in the Species column (J) and notes about it in the Record Notes column (R). There are various misspelt names in the database which I think have arisen by people over-writing or pasting into the Taxon name column. However, I am not entirely certain about this and will find out.

[Mark Powell]

Hi Chris,

I have sent you a message with my email address. I will be happy to send you the spreadsheet with the lichenicolous records in the BLS database (as of about a year ago). I had hoped that this would be made available as a download on the BLS website (along with a ‘health warning’ as there are undoubtedly some errors). However, it was decided not to until the data had been cleaned and, as far as I am aware, this has not been done. So we are currently circulating the spreadsheet ‘informally’. Despite some the issues with the data (most of which are fairly obvious mistakes) this spreadsheet is a really useful resource for simply finding out what has been recorded on what so far in GB&I.

Mark

[Mark Powell]

Hi Chris,

I really must try this spore-drop technique…

However, there may be reasons why lichenologists haven’t traditionally used spore-drops. We often examine herbarium material and I presume that spore-drops only work with fresh specimens. If we started to use spore-drops with fresh material and traditional gentle squashing for herbarium material, we might need two different sets of measurements (our method being probably an inferior method because we will include spores which aren’t quite ‘ready’ to be released).

A year ago an extract was made of all lichenicolous records in the BLS database. I am rather amazed at how few lichenicolous species have been found on Opegrapha s. lat. (the number giving the number of individual records in the database):

Opegrapha areniseda Muellerella 1

Opegrapha atra Milospium graphideorum 1

Opegrapha atra Muellerella polyspora

Opegrapha gyrocarpa Sphinctrina turbinata

Opegrapha herbarum Laeviomyces opegraphae 10

Opegrapha herbarum Muellerella lichenicola 2

Opegrapha niveoatra Laeviomyces opegraphae 26

Opegrapha niveoatra Muellerella lichenicola 1

Opegrapha ochrocheila Laeviomyces opegraphae 2

Opegrapha vulgata Laeviomyces opegraphae 6

Opegrapha xerica Blarneya hibernica 5

Opegrapha xerica Milospium graphideorum 1

The records of lichenicolous fungi in the database (including those presented here) appear to have some errors so don’t accept these unquestioningly. However, it will give you an idea of what has been found on Opegrapha. I don’t know what your fungus is likely to be. I have also repeatedly found a fungus rather like a Taeniolella on Opegrapha ochrocheila but haven’t identified it yet.

Mark

[Mark Powell]

On the subject of UV tests, I have been asked by several people about effective eye protection. The cheap glasses I bought didn’t work. Do you have make and model of the ones you use handy?

Thanks,

Mark

[Mark Powell]

Hi Neil,

Many thanks for these observations. I haven’t got far with investigating Pd/UV reactions except to notice, as you have done, that sometimes a bright fluorescence is seen. This is not the Pd fluorescing (in case anybody wondered) because Pd on an inert, non-fluorescent surface gives a weak mauve fluorescence. I have noticed a Pd/UV+ yellow-orange fluorescence with Pertusaria amara so presumably that was due to the presence of protocetraric acid.

Even if the subtleties of different Pd/UV+ colours are not diagnostic, this could still be very useful (as you suggest) to detect whether any reaction has taken place. I sometimes find it difficult to judge on these Trentepohlia-containing crusts, whether I am looking at a weak Pd+ reaction, or the dull orange of the photobiont showing through, or just the staining from some slightly discoloured Pd solution.

Even if this phenomenon merely shows presence or absence of a Pd reaction, that would be very useful. Chaenotheca stemonea?

Andre Aptroot provided a trial for the K/UV test with some blind specimens that he had previously analysed by tlc. Unfortunately the results were not a perfect match. This is a bit frustrating/interesting/puzzling but I still think that X/UV has value.

Mark

[Mark Powell]

I can’t give you a definite yes or no for M. lichenicola but I suspect that specimens like yours, in calcareous communities and with numerous brown, septate ascospores in the ascus, would often be named as M. lichenicola. One wonders whether there are several cryptic taxa involved. I once had a hypothesis that M. lichenicola on Lecanora campestris seemed a bit different to that on Caloplaca flavescens but I never pursued it properly.

The draft lichenic. key has a tricky couplet where M. lichenicola is separated from others by having more than 64 spores in the ascus. I don’t know whether anyone actually attempts to count them?

Mark

[Mark Powell]

*bluddy* great to see Brian on here. Yes, P. smithii is turning up with some frequency in the east now. The very talented Lewis first sent me a specimen of this from an orchard near Wisbech (?2013) when it seemed like a crazy exotic. Since then, in the past five years or so, we have found P. smithii turning up across the region – my impression is that it is now a scarce colonist. We found a few occurrences of it on oak twigs in Epping Forest on that field trip (where it wouldn’t have been recorded previously).

I don’t currently have any suspicion that the western material is different from the eastern colonists – but you know me, push an alternative hypothesis…

Mark

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