Protoblastenia lilacina?

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chriscant
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Protoblastenia lilacina?

Post by chriscant »

(Very close to our Porpidia specimen,) we found this lichen that looks like it could be Protoblastenia lilacina as there's no K reaction and some hints of violet in the hypothecium. The rock was definitely not limestone but with some basic influence eg Collema glebulentum and Dermatocarpon luridum not too far away - a crag in Swindale not far from Haweswater, eastern Lake District. It had a flaky white thallus and only a few of the larger apothecia were strongly convex. The spores were simple, approx 14x6.5um, some tear-shaped. The apothecia glowed red in UV - which looks like other Protoblastenia do in a quick test outside.

Does this look right for P. lilacina?
Attachments
In situ
In situ
In situ
In situ
Specimen with K applied bottom right
Specimen with K applied bottom right
Section in water
Section in water
Section in K
Section in K
Thallus and apothecia in UV
Thallus and apothecia in UV
Spores
Spores
Hints of violet in hypothecium in K
Hints of violet in hypothecium in K
Neil Sanderson
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Re: Protoblastenia lilacina?

Post by Neil Sanderson »

I have only collected Protoblastenia lilacina once, when the violet in the hypothecium was more extensive, but LGBI3 says:
hypothecium often violet
So the violet in the hypothecium can be absent, or limited as in your specimen and it is the K– reaction that is critical, so this identification looks fine.

Neil
Neil Sanderson
Mark Powell
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Re: Protoblastenia lilacina?

Post by Mark Powell »

I have encountered what I record as P. lilacina occasionally (rather rarely) on limestone memorials in Home Counties' churchyards. At first I was disconcerted by the lack of violet hypothecium in these specimens but such material certainly seemed significantly different to the much more common P. rupestris. Fortunately I often found both on the same memorial, sometimes side by side, allowing for convenient comparison, both in the field and microscopically. I decided that the reaction of the epithecial granules was probably a more reliable taxonomic character than the colour of the hypothecium and currently base my decisions on a combination of morphological characters and (especially) the reaction of the epithecial granules to the addition of K.
Protoblastenia rupestris and P. lilacina growing side by side.
Protoblastenia rupestris and P. lilacina growing side by side.
The epithecium of P. lilacina has a slight reaction when K is added to a section, a proportion of the epithecial granules become deep, dark reddish in colour but there is no bleeding out of substances as reddish solution and the reaction is less dramatic. It is useful to conduct this reaction on some P. rupestris for comparison, when trying to decide whether a specimen in question is P. lilacina.
Sections of P. rupestris and P. lilacina mounted in water.
Sections of P. rupestris and P. lilacina mounted in water.
The same sections after adding K.
The same sections after adding K.
Apothecial sections of P. lilacina (left) and P. rupestris facing each other, after adding K.
Apothecial sections of P. lilacina (left) and P. rupestris facing each other, after adding K.
GFet5sGWIAAks-l.jpeg (21.74 KiB) Viewed 70 times
I suspect that some of the old churchyard records of 'P. calva' were really P. lilacina, a species which seems to have been poorly known by churchyard recorders. P. lilacina is somewhat more like P. calva than P. rupestris in the field, with its darker, more convex discs and less well-developed, often mainly endolithic thallus.
chriscant
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Joined: Mon Jan 28, 2019 9:29 am

Re: Protoblastenia lilacina?

Post by chriscant »

Thanks Neil and Mark

I had reviewed Mark's pics on here, which generally support my proposed id:
https://fungi.myspecies.info/taxonomy/term/7510/media
However my apothecia weren't red, the substrate wasn't hard limestone and the thallus wasn't really thin/endolithic.
Anyway: I'm going with P. lilacina based on the K reaction and faint violet hypothecium.

At one point I thought that we had P. calva on the limestone pavement near us, but now I'm more inclined towards it largely being P. rupestris based on the colour of the thallus; don't know if there's a sure fire way to tell them apart. This P. lilacina was certainly quite white and so could be mistaken for P. calva on that basis.
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