Chris Cant
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chriscant.bsky.social
Chris Cant
@chriscant.bsky.social
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Lichens: the closer you look the more you'll see; zoom out and you'll read the habitat
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chriscant.bsky.social
We have had Sarea resinae from Stanley Ghyll, Cumbria west coast by resin. Can't remember any details but I took these photos.
Sarea resinae Sarea resinae in resin Sarea resinae apothecium ascus tip Sarea resinae apothecium section
September 21, 2025 at 10:34 PM
chriscant.bsky.social
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.
September 20, 2025 at 3:27 PM
chriscant.bsky.social
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
September 20, 2025 at 3:23 PM
chriscant.bsky.social
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
September 20, 2025 at 3:13 PM
chriscant.bsky.social
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
September 20, 2025 at 3:10 PM
chriscant.bsky.social
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!
September 20, 2025 at 3:06 PM
chriscant.bsky.social
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
September 20, 2025 at 3:04 PM
chriscant.bsky.social
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
September 20, 2025 at 3:02 PM
chriscant.bsky.social
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
September 20, 2025 at 2:58 PM
chriscant.bsky.social
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.
September 20, 2025 at 2:53 PM
chriscant.bsky.social
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.
September 20, 2025 at 2:49 PM
chriscant.bsky.social
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
September 20, 2025 at 2:43 PM
chriscant.bsky.social
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
September 20, 2025 at 2:39 PM
chriscant.bsky.social
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
September 20, 2025 at 2:34 PM
chriscant.bsky.social
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
September 20, 2025 at 2:30 PM
chriscant.bsky.social
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
September 20, 2025 at 2:20 PM
chriscant.bsky.social
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
September 20, 2025 at 2:17 PM
chriscant.bsky.social
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.
September 20, 2025 at 1:10 PM
chriscant.bsky.social
@ilichenmoss2.bsky.social‬ We found this possible bryophilous fungus BF on a moss near the first top of Ben Alligin in Torridon in May as lichen by-catch. Hairs coming out of two fruit. Asci and spores seen inside. Spores: 1-septate spores around 20x6.5μm. Any ideas? #Bryophilous #BryophilousFungus
possible bryophilous fungus - spikes/hairs just visible on two black fruit. possible bryophilous fungus - asci possible bryophilous fungus - 1-septate spores around 20x6.5μm possible bryophilous fungus - more 1-septate spores and asci with spores
June 22, 2025 at 2:10 PM
chriscant.bsky.social
Another specimen from Torridon on a terricolous bryophyte mustbe Micarea lignaria var. endoleuca with pale green granular thallus and black apothecia. The thallus has C reaction and is KC+orange as well as P-. Like other M lignaria, it has green epithecium K- and multi-septate spores. #LichenGBI
Micarea lignaria var. endoleuca thallus with apothecia on a bryophyte on the ground Micarea lignaria var. endoleuca epithecium green and our spores up to 6-septate Micarea lignaria var. endoleuca thallus showing C+ yellow/orange ish... Micarea lignaria var. endoleuca: A tissue pressed on to the thallus with K, then with C applied goes orange
June 21, 2025 at 6:37 PM
chriscant.bsky.social
A specimen from Bealach na Bà in Applecross was a lovely lichenicolous fungus Polycoccum trypethelioides forming galls on lichen Stereocaulon condensatum. The black dots are perithecia containing 1-septate brown spores, 8 per ascus. First record of this in the west highlands. #LichenGBI
Polycoccum trypethelioides galls with perithecia on Stereocaulon condensatum at Bealach na Bà in Applecross Polycoccum trypethelioides perithecium section with 8 brown spores in each ascus Polycoccum trypethelioides brown 1-septate spores Polycoccum trypethelioides brown 1-septate spores, with lower cell smaller
June 20, 2025 at 8:19 PM
chriscant.bsky.social
Female ghost moth
Female ghost moth
June 8, 2025 at 10:51 PM
chriscant.bsky.social
Along the Beda Fell ridge were small outcrops and nice heath. Beside the path on peat was Trapeliopsis glaucolepidea, on rock: probably Acarospora subfuscescens infecting another lichen, Nesolechia oxyspora infecting Xanthoparmelia conspersa and Porpidia striata on a pebble. #LichenGBI #springwatch
Trapeliopsis glaucolepidea on a short peat side to the path, puffed up with soredia - no fruit in this case Probably Acarospora subfuscescens fruit infecting another lichen eg Acarospora fuscata. Its fruit have large carbonised and broken margins. Inside were lots of tiny spores in each ascus. Second record for vice-county. This is lichenicolous fungus Nesolechia oxyspora infecting the thallus of Xanthoparmelia conspersa. The black dots are the LF fruit which contains slightly pointed spores, 17.6x5.6μm. First record for vice-county. Porpidia striata on a pebble. The younger fruit just have visible striations on their margins. The fruit exciple is carbonised on the outside. Spores: 19.2x8μm, simple.
June 8, 2025 at 8:05 AM
chriscant.bsky.social
On Friday we had a shortish walk along Beda Fell from Martindale near Ullswater in a dry spell - though still chilly on the 500m top. We saw a Ruby tiger moth and various interesting lichens though round here Lasallia pustulata indicates a lot of sheep. @LichenGBI
Looking along Beda Fell towards High Street Looking back at Yew Crag on the other side of Ullswater Ruby tiger moth Lasallia pustulata - dry
June 8, 2025 at 7:51 AM
chriscant.bsky.social
We had an introduction to the Rhizocarpon genus from a visiting expert who took many samples to confirm some identifications. Lots of other saxicolous species on the rocks and dry-stone walls, including Ochrolechia tartarea and Schismatomma umbrinum. #LichenGBI
Rhizocarpon introduction A lovely Rhizocarpon awaiting identification, with R geographicum also in the picture. Ochrolechia tartarea Schismatomma umbrinum, scratched paler mid-central - this area glows brightly white in UV.
May 23, 2025 at 9:45 AM