Possibly Cladonia squamosa?

[pleb]

Hi,

Another Cladonia which I think is probably Cladonia squamosa. This was growing on the western edge of Dartmoor on a granite boulder.





Any opinions or comments would be very welcome.

Phil

[synangium]

I agree, Phil.

Like many Cladonia spp. it's very variable, but I have seen and photographed C. squamosa resembling this, with its characteristic peeling squamules and holes in the tops of the podetia.

Nigel

[pleb]

Thanks Nigel,

It's good to know we agree so far

I have never been very confident about the differences between Cladonia portentosa and C. ciliata.

This lichen below, though, seems to be in very good agreement with the descriptions of C. ciliata with dichotomous branching and heads leaning over in one direction and it does seem more delicate than C. portentosa.

Found in the same area as Cladonia squamosa, again on a granite boulder.





It would boost my fragile confidence if people agreed with me here

Phil

[synangium]

I think you're right again.

There isn't much of a confidence boost to be found in this sort of tentative agreement!

Nigel

[pleb]

Nigel,

I will take any sort of confidence boost I can find. Cladonia seems so inviting; so many of them just sitting there waiting to be identified, all keyed out in the Floras with detailed descriptions, lots of images on the web, but we know just how frustrating they can be.....

Phil

[synangium]

Yes, often very frustrating - and not just Cladonia - but that must be part of the appeal. Either that, or we've got masochistic tendencies!

Nigel

[AlanS]

I agree with the C. squamosa.

The 'C. portentosa/ciliata' is much more tricky and possibly it is neither, though it is very difficult to tell from photographs.

It could indeed be C. ciliata but it doesn't have the uniformly reflexed branch tips I would expect, and I am not at all convinced.

It could well be C. portentosa, but with it being on Dartmoor, looking a bit delicate, and partly dichotomous, my thoughts turn to someting more unusual.
I suspect, but quite possibly wrongly, that this is C. azorica.

I still haven't seen C. azorica - though it is very high on my photographic hit-list - but this looks a possible candidate. Differs from C. portentosa in being more slender in habit and greater degree of dichotomous branching, but is best separated with a Pd (paraphenylenediamine) test, it reacting orange whereas C. portentosa does not react. Local amongst heathery rocks, etc., predominatly in Wales and the south-west, but not common.

Alan

[pleb]

Alan,

Thanks for your thoughts on the Cladonia which you think is a possibility for C. azorica.

It would be interesting to know exactly which species it is. Not being a lichen specialist, there is nothing more that I can do, but I still have the specimen and I am sure that Barbara Benfield, the Devon based lichenologist, would have a look at it if I asked her, and Pd test it. When I have some feedback from her I will post a message to the WAB Forum.

In my 1992 edition of 'The Lichen Flora of Great Britain and Ireland' by Purvis et. al., C. azorica is not mentioned. Your web site pointed me in the right direction so that I have found images at:

http://www.azoresbioportal.angra.uac...iaazorica1.jpg

but I have no written description to look at as I have no access to 'The Lichenologist'.

Phil

[pleb]

I have had an opportunity to look at a 'Lichenologist' article, read a description of Cladonia azorica, and study a table setting out the differences between C. azorica, C. portentosa and C. ciliata.

With the advantage of still having the specimen to look at, I am sure in my own mind that the lichen in the photo is C. ciliata. It differs from C. portentosa by having mostly dichotomous branching and being more delicate in appearance.

C. azorica is said to have terminal branches that are "never recurved or orientated" while the specimen in the photo has these characters.

So, purely on observable characters and without any chemical testing, I feel that it is C. ciliata.

Phil

[AlanS]

Hi Phil,

I have delayed replying to this for various reasons. Heavy workload and health problems have kept me away from this forum for a while, and also I have been going through a lot of my Cladonia ciliata material and have revised and extended my web page:

Cladonia ciliata (images of British lichens)

I still agree that your photographed material quite likely is rather poor C. ciliata, but I should also point out that delicate states of C. portentosa are often dichotomously branched and can be deflexed and somewhat oriented at the tips.

Many of the branches of your material look straight and there is little sign of the "combed" appearance of C. ciliata. Inasmuch as it provides diagnostic value, the whitish colour of your material is more that of C. portentosa.

As I say, I have yet to see C. azorica and consequently have no understanding of it, but the original description of the species (Ahti's monograph on this group) states that the ultimate branch tips are "erect or deflexed". His photograph of the material on which the name is based (i.e. the most authentic possible azorica) was unhelpfully of more or less white material against a white backgound, and then the printing quality was not good. However, looking at it with a magnifying glass and comparing it with your photographs, I still wouldn't rule out azorica as a possibility. Regarding your quote from the Lichenologist paper, "never" is not a good word to use in subgenus Cladina. Probably you are right, the branches of your material are indeed too recurved and maybe oriented, but these characters are not totally diagnostic.

On balance, I think this is a delicate state of C. portentosa, but I really do find that Pd testing is necessary in these doubtful cases. A general rule seems to be that if the material is not clearly and obviously C. ciliata, then most likely it isn't! But there again you have the actual material and can judge it better than I can.

Alan