Lecanora (?) sp. from Denmark

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JonasRavn
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Lecanora (?) sp. from Denmark

Post by JonasRavn »

This one is causing me all kinds of problems. It was found in April in western jutland, Denmark, growing on the bark of an old Pinus sylvestris. I thought both morphology and ecology was good for Lecanora cadubriae, but the chemistry doesn't agree. The specimen is K+ yellow turning at most slightly orange (K/UV+ bright yellow), P- or P+ slightly yellowish (P/UV+ orangeish yellow) and C-. The spores measure around 13-15 x 5-6 µm and the ascus type looks to me like the bacidia-type, but judging the biatora/lecanora/bacidia-types is not straight forward for me. Furthermore some of the blue color went into solution when doing the K/I "stain" which might be of diagnostic importance?
There seems to be both epithecial and excipular crystals which are all soluble in K.
I have included a bunch of photos, hoping someone can point me in the right direction.
cf. Lecanora sp. 1-1.jpg
Section, 400x
Section, 400x
Spores, 1000x
Spores, 1000x
Spores in ascus, 1000x
Spores in ascus, 1000x
Excipulum, 1000x
Excipulum, 1000x
Section 100x, polarized light, mounted in water
Section 100x, polarized light, mounted in water
Section, polarized light, mounted in K
Section, polarized light, mounted in K
Section during K/I-staining. Blue colour going into solution.
Section during K/I-staining. Blue colour going into solution.
Ascus K/I
Ascus K/I
Ascus K/I
Ascus K/I
Last edited by JonasRavn on Sat May 07, 2022 1:34 pm, edited 1 time in total.
JonasRavn
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Re: Lecanora (?) sp. from Denmark

Post by JonasRavn »

Here's a photo of the K/UV-reactions
cf. Lecanora sp. 1-2.jpg
AlanFUSA
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Re: Lecanora (?) sp. from Denmark

Post by AlanFUSA »

My guess would be something in Ramalinaceae. Perhaps a Biatora, but no idea which one.
Mark Powell
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Re: Lecanora (?) sp. from Denmark

Post by Mark Powell »

Your enquiry prompted me to re-examine a specimen which I had, somewhat tentatively, identified as Lecidea exigua. There are many similarities between my material and yours but perhaps not an exact match. I am not providing a definite determination (I am hesitant even about naming my own material) but, in the absence of suggestions from others, perhaps my observations will provide another line of investigation.
exigua3.jpg
My specimen (above) is from the smooth bark of an apple tree in a Kent orchard. It has apothecia (250-)300-350 microns in diameter. The disc has a slight pruina due to coarse epithecial granules. The thallus is indistinctly warted, sits on a slight black prothallus (visible where the thallus is thin) and forms conspicuous black lines where it meets neighbouring lichen thalli. The thallus shows a patchy UV+ orange fluorescence, it is K+ yellow (yellow turning slightly orange as in yours). It is K/UV+ yellow (perhaps slight green hint). I suspect this K/UV+ yellow is indicating the presence of a xanthone (rather than atranorin). It is C- but I think the K reaction is slightly deepened more orange when C is applied to the spot (i.e. probably KC+ orange).
exigua1.jpg
exigua2.jpg
exigua7.jpg
exigua6.jpg
Above are three sections in water and one in K. The coarse epithecial granules dissolve in K. My specimen had rather inconspicuous small crystals in the exciple, mainly towards inner parts, soluble or mainly soluble in K. The ascospores look a bit fatter than in your material (typically e.g. 11 x 5.5) but similar dimensions.

I was particularly interested to see what the ascus tips were like in my specimen. The afl website states that L. exigua has a Lecidea-type ascus but this is not illustrated and may be an assumption (the same page states that Lecidella elaeochroma has a Lecanora-type ascus which is incorrect, an error also in LGBI2, L. elaeochroma having a Lecidella-type which is more like a Bacidia- or Biatora-type).
https://www.afl-lichenologie.fr/Photos_ ... exigua.htm
The asci of my material have similar ascus tips to your material, and rather similar to those in Lecidella as shown below.
exigua4.jpg
exigua5.jpg
I'm sorry that I can't give any definite identification but I was struck by some of the similarities between your material and my specimen which I have tentatively concluded must be L. exigua. L. exigua is supposed to grow mainly on smooth bark of deciduous trees but there may be overlap of species on deciduous trees and the smooth bark plates of old conifers. I am not even certain that our material is the same taxon but seems to be the 'same sort of thing'. Perhaps there is more than one taxon that has been named as L. exigua (it seems to be a rather poorly understood lichen with only scanty published descriptions).
JonasRavn
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Re: Lecanora (?) sp. from Denmark

Post by JonasRavn »

Thank you for your replies, Alan and Mark.

I have been/still am busy with field work, but tonight I had some time to follow up on your input.
I am not much closer to an ID, but your suggestions prompted me to do some more testing/staining that might help.
First of all, some apothecia have a bluish pigment in the excipulum (consistent with the Lecidea-hypothesis?):
Billede3070.jpg
The brown epithecial pigment reacts N+ red and the crystals are not soluble in N:
Section in water
Section in water
Section in N
Section in N
JonasRavn
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Re: Lecanora (?) sp. from Denmark

Post by JonasRavn »

I made an k/ink/vinegar-stain and found that while some paraphyses were simple, branching and anastomosis was common:
Billede3080.jpg
And much to my surprise, some spores appeared one-septate (I found three out of ~50 spores like this):
Billede3081.jpg
Lastly a picture of the excipular hyphae:
Billede3083.jpg

The thallus might have an extremely faint UV+ orange reaction (only barely visible with powerful torch in pitch black room, xanthone?), but it is too weak to capture on a photograph.

I have tried keying it as a Lecidea without much luck - it shares some characteristica with L. hypopta, but it is not a perfect fit. I cannot rule out L. exigua, but the paraphyses do not appear capitate above which causes some hesitation.
The Revision of British and Irish Lichens vol .11 (Ramalinaceae) points me in the direction of Biatora, but it does not key out to anything meaningful.


I hope these new pictures might shed some light on the true identity of my specimen.
Last edited by JonasRavn on Tue May 17, 2022 8:42 pm, edited 1 time in total.
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