Lichens to ID/confirm

[lettuce]

Hello again!

1) I visited some Prunus spinosa bushes yesterday and found Physcia aipolia on some of its twigs. I also found this lichen which resembles it, but doesn't have any apothecia, only pycnidia. Can you confirm this is also P.aipolia? Is there a specific reason that one lichen has apothecia while the other has pycnidia only?

*lower left corner presents conidospores

2) Not far from the location above was a felled Fraxinus angustifolia, so I decided to check its twigs and branches for any interesting lichens, primarily those new to me. I found what, at first glimpse, looked like a lichen belonging to one of those genera like Graphis etc. I made a section through an apothecium and found no algal layer. So this might just be an Ascomycota fungus? Also, I couldn't make out any spores in the asci, even after squashing.
If this is a fungus, perhaps some of you may be familiar with this species because of its specific looks? Should I post it under the Fungi main forum? I'm really interested to find out what this is!


3) This one really packed a headache - identification wasn't easy and cutting a section was one of the fiddliest things I've done. Anyway, using Smith 2009 and Wirth 1995, it keyed out as Lecania. Smith mentions blastidia, soralia and papillae, but because I was working only with apothecia, I had no ways of observing these structures. This brings up a question: if you take a look at the 1st photo, is the thallus that whitish mass near the brown apothecia? It is so minute and even though I know what blastidia are in theory, I wonder if I would recognize it in this case.
Sorry for chatting you up... Here are some details: spores mostly 1 septate (some are simple; perhaps yet immature spores), colorless, 8 per ascus; asci Bacidia - or Biatora-type (couldn't make out the fine detail); epithecium brown; paraphyses simple or dichotomous near the top, apex a bit swollen and dark brown. Substrate: concrete. No chem.reactions, though on a couple of occasions the part below the algal layer leaked yellow in K (was visible in sections only), not sure if this is relevant. Using Wirth 1995, keys out as Lecania inundata... would you agree?

Spore discharge video




Thanks for reading, I appreciate any insight.


Dragan

[AlanS]

As I posted before, those of us habitually in this forum are likely not to have much knowledge of Croatian lichens. We might suggest names, but we don't have much means of checking that they will be applicable away from the oceanic west. So anything I post is speculative and has to be checked against local information.

Anyhow:

1. I am fairly sure this is not Physcia aipolia. It looks rather more like P. stellaris - which can have inconspicuous pseudocyphellae, especially on older parts of the thallus, contrary to the account in Smith et al. In doubtful cases it is best to test the medulla with KOH (yellow in aipolia, no reaction in stellaris, but the cortex of both species reacts yellow so it is necessary to strip this off). I would expect P. stellaris to have apothecia, but not so abundantly as aipolia and this is a young thallus. The thallus is rather "lumpy" as in P. stellaris, and the younger lobes seem to lack pseudocyphellae. But I am not at all positive.

2. I agree this is a graphoid lichen but it is not one I know (which still leaves a lot of scope!). I don't think any of these have algae in the apothecial tissues (he says not bothering to check). In view of the fact that mature spores are often needed for certain identification of these species, it is surely inevitable that many collections will not have them, even in seemingly mature apothecia. This may be sheer bloody-mindedness on the part of the lichen but I suspect it is actually an evolutionary effect - if we are repeatedly discouraged we may give up collecting samples of these things. Surely parallel evolution in Porpidia!

3. I don't know Lecania inundata, it is a rather local and rare species with us, but I agree your photo shows a member of the Lecania erysibe group, and the conspicuous (and non-blastidiate?), thalline margin does favour L. inundata. I would expect L. erysibe to be the more likely on concrete, so worth double checking, but I think you are right.

Alan

[lettuce]

Alan, thanks very much for another detailed reply! Regardless of your knowledge of Croatian lichens, I very gladly accept and value all opinions.

1) Oh, thanks for pointing that out, it does seem more like P.stellaris! I managed to scrape off a bit (thallus was, by the way, quite brittle) and it gave no reactions with K. I guess I was confused by the pseudocyphellae on the older part of the thallus. So next time I should only check the younger lobes for pseudocyphellae and these will be more conspicuous in P.aipolia, correct?

2) This mysterious graphoid lichen has just increased my interest to find out what it is.


Dragan