aspeca

Dear Neil —

Very many thanks for this advice. It really clarifies matters for me. I was looking for K+ yellow turning red because LGBI3 glosses the ‘K+ yellow-red’ in LBGI2 as ‘presumably yellow -> red’. It’s helpful to know that you yourself haven’t ever seen that reaction with C. cryptochlorophaea, and I’m pleased that my suspicions weren’t misplaced that I was perhaps just looking at a typical brownish K-reaction to fumarprotocetraric acid.

Your pointer on the KC-test is especially useful. I was a bit excited about the possibility of having witnessed this ‘KC+ wine-red’. I thought the phrase meant perhaps more a light beaujolais than a deep cabernet — but from your description it sounds more the other way round. Perhaps I should just stick with the catch-all C. chlorophaea sens. lat. going forward!

Thanks for the steer to C. cyathomorpha, which I’d discounted because I thought the veining would be more obvious than you’ve explained. Another bit of fieldcraft that’s good to know. I’ll examine the larger squamules on my specimen for any evidence.

Enjoy your Cornish fieldwork — glad the goats are cooperating with rare lichen conservation!

Thanks again,

Anthony

Pier-Luigi did reply to the specific question about the value of differentiating between the two varieties of P. furfuracea. He agrees that they’re just chemical strains, and he suggests that the rank of forma (lower in the taxonomic tree than varietas, and indicating more minor differences) might be better in this case.

At the same time, he favours retaining the two varieties because he thinks that evidence suggests that there are important ecological/distributional differences between them. As you pointed out, Di, LGBI3 also agrees that P. furfuracea var. ceratea appears more common in the UK, and particularly more abundant in the north. Not sure if there’s an explanation why, but without recording varieties, the data wouldn’t exist to support one.

And more generally, Pier-Luigi takes the view that ‘taxonomists should provide names not only for taxonomists’, and that infraspecific epithets such as varietas and forma are a good way to capture information such as ecology, distribution, etc. I take it that he’s reminding us that taxonomy isn’t wholly the same as phylogeny, at least below the level of species.

Screenshots of his thread:

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Excellent stuff, Di! I’d seen that Hawksworth and Chapman paper on P. furfuracea before, but I’d completely forgotten it. The further references that you’ve dug up on a KC+ reaction to physodic acid makes me more confident to leave my record as P. furfuracea var. furfuracea.

It also adds to the question of whether it’s valuable to revisit the species description for P. furfuracea in LGBI3, if not to correct then perhaps at least to qualify the spot-test results listed there. Also the description in ITALIC 7.0 — perhaps I’ll send a message to Pier-Luigi to ask for his views.

Of course, this is all compatible with Paul’s point that the production of physodic or olivetoric acid in P. furfuracea isn’t phylogenetically significant. So his implied question remains over whether we should be recording these varieties separately in the first place.

That said, insofar as the various BLS numbers are all there to use, your finds certainly help to clarify the way forward for us in the field!

Many thanks for that very helpful reply, Di. It’s good to know that others have shared my experience with C- but KC+ red P. furfuracea, and what’s more that I didn’t simply mistake a fleeting or weak C-reaction for a negative! I collected my specimen while on holiday in the North Pennines, and as it’s pretty uncommon in East Anglia, it would be difficult for me to investigate further.

It does seem to make sense to consider such specimens as P. furfuracea var. furfuracea, because as you say the C-test is decidely negative. As mentioned, I recorded my specimen back in December as P. furfuracea var. furfuracea following Dobson, and I’m happy to leave it there for now for the same reason.

But that’s to say that the KC-test isn’t diagnostic, but the C-test is. I’m wary of completely committing to this Dobson/Lichens Marins/Wirth position without understanding why the LGBI/ITALIC 7.0 (and as you found also AFL Lichenologie) species descriptions differ!

I’m also wary of using the BLS number for P. furfuracea sens. lat. to record these specimens, unless e.g. Paul Cannon specifically directs it. My worry is that it’s possible that number was used at a time when P. furfuracea hadn’t yet been distinguished from other species, and the data tagged with it is classed as unreliable. But maybe not — I don’t know myself what the history of that BLS number might be.

If you find more of this C- but KC+ red P. furfuracea in Warwickshire, I’d be keen to hear about it!

Thanks, Neil.

I was originally thinking Pertusaria hymenea as well. But I discounted it not only because the thallus wasn’t C+ yellow and because there were only four spores per ascus, but also because the epihymenium didn’t appear to be K+ violet. (I should have mentioned that the unstained micrographs were mounted in K.)

On an unrelated note — if you have the chance, I’d be glad of your opinion on a previous post about Cladonia chlorophaea (7th June).

Thanks again,

Anthony