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Chris Cant @chriscant.bsky.social · 20d

We have had Sarea resinae from Stanley Ghyll, Cumbria west coast by resin. Can't remember any details but I took these photos.

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Chris Cant @chriscant.bsky.social · 20d

Great intro to two remnants of Scotland's Caledonian Forest in the Loch Lomond and Trossachs National Park: Glen Falloch and Coille Coire Chailc with a brief shot of Platismatia glauca. These woods need to be allowed to regenerate and join up.
www.youtube.com/watch?v=DSDV...

Loch Lomond's Hidden Caledonian Forest

YouTube video by cridhe

www.youtube.com

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Chris Cant @chriscant.bsky.social · 20d

Sigh or swear is the usual first response. Then: nothing. The old names should always work in the spreadsheet. The new names are in the taxon dictionary, but not marked as "Current" yet. And they are not in the spreadsheet. Eventually we may get used to them.

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Chris Cant @chriscant.bsky.social · 21d

There is a suggestion that the I needs to have some acid in for it to work. We'll have to try it with our K and I to see if it works.

I've seen pics of the more-than-2-celled Caloplaca but don't think we've seen it. Nice one

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Chris Cant @chriscant.bsky.social · 21d

At RGBE, "E" herbarium there is a searchable database of some of their specimens, which includes a Fissurina alboscripta specimen that we collected in 2019 from Assynt. #LichenGBI
data.rbge.org.uk/herb/E01002151

Royal Botanic Garden Edinburgh - Herbarium catalogue

Royal Botanic Garden Edinburgh (RBGE) is a world-renowned scientific centre for the study of plants, their diversity and conservation.

data.rbge.org.uk

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Chris Cant @chriscant.bsky.social · 21d

As some light relief we were given a tour of the Royal Botanic Gardens Edinburgh (RBGE) herbarium "E" by Assistant Herbarium Curator (Cryptogams) Heleen Plaisier. We had an intro on how specimens are stored and how they can be accessed. #Rhizocarpon #LichenGBI
data.rbge.org.uk/search/herba...

In the E herbarium at a set of drawers with British Lichens

In the E herbarium an open cabinet of specimens

There were several specimens of Catolechia (Epilichen) scabrosa, some in matchboxes so as to help preserve the shape, no doubt provided by eminent lichenologists.

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Chris Cant @chriscant.bsky.social · 21d

Eric then shared his PhD work on the Poeltinula hochstetteri complex which could be split into an s.str. etc. We looked at a couple of samples and saw differences in the observed features which might show to different species. Our razor blades were seeing cutting edge stuff! #Rhizocarpon #LichenGBI

Eric Möller presents his work-in-progress on the Poeltinula hochstetteri complex.

A specimen from Norway with a Poeltinula hochstetteri species.

Where another Poeltinula hochstetteri species had been sampled for TLC.

Poeltinula hochstetteri s.str. (I think) showing dark capitate paraphysces

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Chris Cant @chriscant.bsky.social · 21d

Stretching our brains, Einar discussed the various techniques that they have used in Oslo to analyse the DNA sequences that they've seen. Various tools help build putative taxonomic trees, grouping specimens together into clades that may or may not represent (new) species. #Rhizocarpon #LichenGBI

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Chris Cant @chriscant.bsky.social · 21d

John Douglass looked at our specimen of Rhizocarpon geminatum. However he re-determined it as Rhizocarpon subgeminatum as the epiithecium was green, the spores were colourless (except over-mature ones), the spores were small and has more than two spores per ascus. #Rhizocarpon #LichenGBI

Rhizocarpon geminatum re-determined as Rhizocarpon subgeminatum

Rhizocarpon geminatum re-determined as Rhizocarpon subgeminatum notes

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Chris Cant @chriscant.bsky.social · 21d

The colour of the epithecium and whether it changes colour in KOH can be an important indicator - if you can see it. I think the options are a K- dark epithecium and green upper hymenium - or a dark epithecium which goes slight red in K. #Rhizocarpon #LichenGBI

Poeltinula hochstetteri has a dark epithecium and K- green upper hymenium

Rhizocarpon polycarpum showing the K+red epithecium

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Chris Cant @chriscant.bsky.social · 21d

Looking at Rhizocarpon spores will be of great help to get something to species. #Rhizocarpon #LichenGBI

In the Rhizocarpon group, many spores are 1-septate, some are sub-muriform and others are more fully muriform. The size of the spores is important, so measure a few mature ones. You also need to decide whether spores are colourless or brown/green when mature. The ones shown here are mostly colourless but the R alpicola ones are most green when mature. Some colourless ones do shrivel and go brown when over-mature!

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Chris Cant @chriscant.bsky.social · 21d

Back on day one of the Rhizocarpon course, it was demonstrated that testing the medulla with KI was a good test for these genera. Some species show an amyloid I+blue reaction. #Rhizocarpon #LichenGBI
en.wikipedia.org/wiki/Amyloid...

Pick off a chunk of thallus onto a slide then put blobs of KOH and Lugol's Iodine nearby. The Iodine we were using had lactic acid in to help the reaction. Under a dissecting scope, drag in some K then drag in some I.

We tested Rehmia reducta and, as expected, found it I-

Rhizocarpon geographicum showed a swirl of I+blue

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Chris Cant @chriscant.bsky.social · 21d

On yellow map lichens Mike Haldeman gave a great talk from North America, heroically early in the morning before work. Mike had been looking at the Rhizocarpon geographicum group, an extremely polymorphic and still poorly understood species complex. #Rhizocarpon #LichenGBI @brucemccune.bsky.social

Mike Haldeman suggested counting the spokes of areole joints of apothecia in Rhizocarpon geographicum

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Chris Cant @chriscant.bsky.social · 21d

We were very pleased to be able to have a look at three separate Rhizocarpon alpicola specimens as we had been looking for this in Langdale. The specimens varied quite a bit and only a few areoles exhibited the classic eyeball of an apothecium surrounded by one areole. #Rhizocarpon #LichenGBI

Rhizocarpon alpicola behaving and showing a classic eyeball with an areole bulging and surrounding the apothecium.

Rhizocarpon alpicola showing a Pd+yellow medulla top right

Rhizocarpon alpicola spores were 1-septate, possibly with an extra very thin septum just visible, turning green/brown as they matured.

Rhizocarpon alpicola GB distribution map

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Chris Cant @chriscant.bsky.social · 21d

When looking at the yellow-green Rhizocarpon species the arrangement of the areoles and apothecia is important. (Click for more) But these characters are not clear. There are other things to look for eg R alpicola has 1-septate spores.#Rhizocarpon #LichenGBI
claude.ai/public/artif...

Rhizocarpon geographicum is surrounded by angular areoles (A), less common Rhizocarpon lecanorinum is surrounded by one areole for more than half its circumference a C shape (B) while rare Rhizocarpon alpicola has areoles that go all the way round the apothecium. Both Rhizocarpon lecanorinum and Rhizocarpon alpicola can have a bulging eye-ball look.

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Chris Cant @chriscant.bsky.social · 21d

For #Rhizocarpon the apothecia arise from the hypothallus, not from areoles. Apothecia may look as though they are sat on an areole, but they aren't. Apothecia are surrounded by areoles, providing energy to make the fruit. I need to do a vertical section to prove this. #LichenGBI

Rehmia amphibia (Rhizocarpon amphibium) showing large and small apothecia. It's probably just visible that the apothecia arise from between the areoles.

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Chris Cant @chriscant.bsky.social · 21d

The most common UK Rhizocarpon is R. reductum now called Rehmia reducta. It's got a grey to brown, cracked areolate thallus, rough disc, small muriform ascospores and usually K+ yellow, Pd+ orange colour reactions. #Rhizocarpon #LichenGBI

Rehmia reducta thallus and black apothecia with roughened surface

Rehmia reducta showing a K+yellow chemical reaction

Rehmia reducta (Rhizocarpon reductum) distribution map for GB and Ireland

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Chris Cant @chriscant.bsky.social · 21d

In the UK, Rhizocarpon geographicum is ubiquitous in the uplands on siliceous rocks with its multiple yellow-green thalli with dark edges giving it its common name "map lichen". There are other yellow-green species but R geog always has angular areoles around fruit. #Rhizocarpon #LichenGBI

Rhizocarpon geographicum is ubiquitous in the UK uplands on siliceous rocks with the yellow-green thalli having dark edges which give the appearance of a map giving its common name map lichen.

Rhizocarpon geographicum always has angular yellow areoles around the black fruit

UK and Ireland distribution map for Rhizocarpon geographicum

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Chris Cant @chriscant.bsky.social · 21d

Here's a list of the Rhizocarpaceae name changes affecting the UK, including an earlier Rhizocarpon oederi change.

Perhaps Poeltinula cerebrina needs moving from Poeltinula???!

#Rhizocarpon #LichenGBI

claude.ai/public/artif...

Rhizocarpon oederi → Haugania oederi

Epilichen scabrosa → Catolechia scabrosa
Rhizocarpon amphibium → Rehmia amphibia
Rhizocarpon anaperum → Rehmia anapera
Rhizocarpon caesium → Poeltinula caesia
Rhizocarpon chioneum → Rehmia chionea
Rhizocarpon cinereovirens → Rehmia cinereovirens
Rhizocarpon furfurosum → Rehmia furfurosa
Rhizocarpon hochstetteri → Poeltinula hochstetteri
Rhizocarpon infernulum f. infernulum → Poeltinula infernula
Rhizocarpon infernulum f. sylvaticum → Poeltinula sylvatica
Rhizocarpon lavatum → Rehmia lavata
Rhizocarpon petraeum → Rehmia petraea
Rhizocarpon postumum → Rehmia postuma
Rhizocarpon rubescens → Rehmia rubescens
Rhizocarpon reductum → Rehmia reducta
Rhizocarpon subpostum → Rehmia subpostuma
Rhizocarpon timdalii → Rehmia timdalii
Rhizocarpon umbilicatum → Rehmia umbilicata

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Chris Cant @chriscant.bsky.social · 21d

The Rhizocarpaceae genus changes can be summarised in this diagram, with Epilichen scabrosa becoming Catolechia scabrosa and Rhizocarpon splitting into Rhizocarpon, Rehmia and Poeltinula. #Rhizocarpon #LichenGBI

claude.ai/public/artif...

Catolechia → Catolechia
Epilichen → Catolechia
Haugania → Haugania
Poeltinula → Poeltinula
Rhizocarpon → Rhizocarpon
→ Rehmia
→ Poeltinula

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Chris Cant @chriscant.bsky.social · 21d

And they are looking at possible splits in Poeltinula (Rhizocarpon) hochstetteri s. lat., while lichenologists in North America are looking at the Rhizocarpon geographicum agg. - more later.

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Chris Cant @chriscant.bsky.social · 21d

By looking at DNA sequences from Norway and across the world, Einar and Eric from Oslo have recently published a paper with some taxonomic name changes in the Rhizocarpaceae Rhizocarpon group.
#Rhizocarpon #LichenGBI

fuse-journal.org/images/Issue...

fuse-journal.org

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Chris Cant @chriscant.bsky.social · 21d

Thanks very much to Rebecca Yahr for being the local organiser at RGBE, providing the workshop and lab facilities for the enthusiastic group of BLS rhizocarponeering lichenologists from all over GB.
#Rhizocarpon #LichenGBI @britishlichensociety.org.uk @thebotanics.bsky.social

Lichenologists at work in the Teaching Lab at RBGE on the 2025 Rhizocarpon course

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Chris Cant @chriscant.bsky.social · 21d

Thanks very much to Einar Timdal and Eric Möller at the Natural History Museum, University of Oslo for leading the @britishlichensociety.org.uk #Rhizocarpon course last week at Royal Botanic Gardens Edinburgh (RBGE). And John Douglass for presenting a guide to UK Rhizocarpon. #LichenGBI

Einar Timdal from the Natural History Museum, University of Oslo giving an introduction to the Rhizocarpaceae genera

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Chris Cant @chriscant.bsky.social · 21d

You can now get free Extended Security Updates to Windows 10 for another year. You need a Microsoft account and have done a backup. This can be a full system backup onto an external USB disk, no cloud. Use Backup and Restore (Windows 7) then Create a system image.

techonthego.co.uk/2025/07/micr...

In Windows 10, go to Files backup then Backup and Restore (Windows 7). Once there, select Create a system image.

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