More unidentified lichens from my latest walk.

[diatom dave]

Here are my latest finds from Sundays walk. I think the first could possibly be Ramalina farinacea except for a niggling doubt about the nature of the soralia. According to Dobson these should be disc-like or oval which these don't seem to be. Neither are they entirely confined to the margins of the branches (see first enlargement). Could this specimen be subfarinacea? Dobson does say the soralia are more excavate in this species. The second enlargement shows the tips of the branches....what are the little dark dots at the ends of the tips? My next offering seems to be very common in my area coating the boles of many trees, leprose I think but this really has me guessing...as does the next crustose type which is K-, if that's any help. The last one I found encrusting a wall of a derelict building, is this actually a lichen? Any help is greatly appreciated.

[JennyS]

Hi Dave,
The last photo is an algae, a Trentepohlia: Irish lichens, algae - Trentepohlia

[Lancashire Lad]

I will more than likely be proved wrong (again ), but to me, the second to last one looks like it might be Porpidia tuberculosa.

Regards,
Mike.

[diatom dave]

Thanks Mike...I wondered whether it was P. tuberculosa but with my very limited knowledge I was far from sure. The crustose types are not easy at all.

[diatom dave]

Originally Posted by JennyS

Hi Dave,
The last photo is an algae, a Trentepohlia: Irish lichens, algae - Trentepohlia

Thanks Jenny for your help. Now I know what it is, I've been looking at Alan Silverside's really excellent site and found out quite a lot about them. The Trentepohlia genus are fascinating in themselves and I can see me being sidetracked to study them in more detail! In my area of the South Pennines there seems to be at least two or three different species for me to get to grips with. Once again thanks for the info.

[Lancashire Lad]

Originally Posted by diatom dave

....The crustose types are not easy at all.

You're not kidding - and my knowledge is probably just as limited, if not more so, than yours. - It's very fortunate that there are some very knowledgeable contributors to WAB, (like AlanS & JennyS), otherwise I'd be up the creek without a paddle on most occasions.

Regards,
Mike.

[AlanS]

Originally Posted by diatom dave

Here are my latest finds from Sundays walk. I think the first could possibly be Ramalina farinacea except for a niggling doubt about the nature of the soralia. According to Dobson these should be disc-like or oval which these don't seem to be. Neither are they entirely confined to the margins of the branches (see first enlargement). Could this specimen be subfarinacea? Dobson does say the soralia are more excavate in this species. The second enlargement shows the tips of the branches....what are the little dark dots at the ends of the tips? My next offering seems to be very common in my area coating the boles of many trees, leprose I think but this really has me guessing...as does the next crustose type which is K-, if that's any help. The last one I found encrusting a wall of a derelict building, is this actually a lichen? Any help is greatly appreciated.

Hi Dave,

Sorry to be away from the forum for a while (pressure of other work). [Probably also the shock of meeting JennyS at a workshop - efficient, hard-working people are scary. ]

Anyhow, I have looked carefully at your first three photographs and I am confident they are Evernia prunastri, not a Ramalina. Sometimes Evernia can look quite like Ramalina farinacea, but as you correctly recognised, the soralia are different. The black spots are the conidia of the lichen (probably a precursor to the sexual stage, but surpisingly this is still uncertain.) As you see here, in Evernia they are inconspicuous and often marginal.

Black spots on lichens can also be parasitic fungi, or even other parasitic or invading lichens, but not here I think.

Photograph 4 is a Lepraria and here is where problems start. It used to be simple a few years ago and we called them all "Lepraria incana", and this name was much used for powdery crusts in areas of fairly high sulphur dioxide pollution. However, there are now several rather poorly defined morphological entities (I use the term "morphospecies" for these), but chemical testing, especially thin-layer chromatography, reveals the existence of quiet a number of extra "species". As in other taxonomic groups where reproduction is entirely asexual, defining a workable species-concept is difficult or impossible.

Two of the most common "species" on trees are true Lepraria incana, which is usually distinctly bluish, thin and lacking a white medulla under the granules, and grows on acidic bark, and L. lobificans, which has a thicker, pale blue-green thallus with an underlying white medulla and minutely projecting hyphae (like "hairs") visible with a good lens, often coating the boles of trees, just as you describe. However, I cannot see a medulla in your photograph and the overall thallus looks a little thin.

If this were my specimen and I had the necessary chemicals and other apparatus to hand, I would:
a) seriously question why I didn't have something else more useful to do;
b) initially check the possibility of it being L. sylvicola (supposedly common in the west).
But this is just speculation.

Agree Porpidia tuberculosa.
Agree Trentepohlia, looks like T. aurea.

Alan

[JennyS]

Sorry to be away from the forum for a while (pressure of other work). [Probably also the shock of meeting JennyS at a workshop - efficient, hard-working people are scary. ]

Ow. Me efficient - I don't think so!

If I seemed hard working and efficient at that workshop it was only that I was totally out of my depth, floundering and trying desperately hard (but without much success) to get the * microscope in focus........
By the end of Sunday afternoon I finally succeeded in cutting a section I just about got into focus and even then it turned out to be a fungus spore I was peering at!

[diatom dave]

Thankyou AlanS for your invaluable help. Even though there are numerous other things I should really be doing, like mowing the lawn, planting the flower beds etc. I will somehow manage to find the time to subject my Lepraria specimen to a few chemical tests and tell you what I find. As for JennyS and her skills as a microscopist... I bet she is far more adept than she's letting on.