Possible Reichlingia or Arthonia ?
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December 7, 2025 at 12:52 pm #33122
Could I seek an opinion on this crustose lichen growing on a middle aged Oak tree bark in a mixed local Wood. The embedded rough surfaced slightly sunken apothecia had me baffled at first but after further research am now leaning towards one of the Reichlingia or Arthonia lichen. December 7, 2025 at 3:17 pm #46782This looks quite a bit like Lecanographa lyncea. Did you find it in Warwickshire? The map shows a couple of old records so a brilliant find if it is this species. It reacts ice blue with the UV torch but negative with all other reagents. December 7, 2025 at 3:23 pm #46783Not any Reichlingiaspecies, as too robust. I would need to know what the spores are like, but Lecanographa lynceais a strong possibility as Maxine says. Otherwise, potentially an oddly developed Phaeographisspp, most likely Phaeographis dendritica, but it looks much more like Lecanographa lyncea. Neil
December 7, 2025 at 4:43 pm #46784You can check out P. dendritica by seeing if it gives a red reaction with KOH. December 7, 2025 at 4:48 pm #46785Lecanographa lynceaalso gives the UV/K(wet)+ mauve spot test for confluentic acid. Neil
December 8, 2025 at 3:23 pm #46786Maxine many thanks – the sample was indeed VC38 on the West side – and everything visually seems to fit Lecanographa lyncea perfectly. I had previously tried the usual K & C & UV tests on the Thallus and there was no reactions.
I retried the UV on the Thallus again today but no reaction that I could detect.
I then moved onto Neils K/UV when still wet and again no colour mauve was detected on the Thallus. When drier some orange maybe.
Whether its my technique or not I don’t know although the UV has worked on the few other samples I tested in the past.
Lastly I rechecked the dry Kred and this was still -ve.
For now I have retained the sample until I can move onto using a microscope.
Thank you both for the Input.
December 19, 2025 at 7:32 pm #46787Just an update to fully close this one out. Brian very kindly assisted by having a look at the sample and his reply back to me was –
” It’s funny how misleading a photo can be. I immediately recognized it when taking it out of the packet (confirmed microscopically) as Phaeographis smithii. So, the second record for this species from Warwickshire”.
Many thanks again particularly to Brian for his valuable time with this.
January 11, 2026 at 12:51 pm #46788As a postscript to this lengthy thread I would like to add an observation re Phaeographis species. During a recent survey in South Devon and Dorset I examined every Phaeographis thallus encountered and found a huge predominance of P. smithii over P. dendritica. Looking at our distribution maps P. dendritica has been more widely recorded. Is this due to a decline in P. dendritica now or were few of those records checked microscopically? Luckily the difference between these 2 can be seen using a handlens or dissecting microscope in most cases.
Happy new year everyone!
Maxine
January 12, 2026 at 10:30 am #46789Maxine What habitats was this in?
Phaeographis smithiidominates on twigs (where yes Phaeographis dendriticaprobably has been over recorded), has very definitely spread a lot beyond its core 20th C area and maybe has also recently increased in abundance within that core area. Phaeographis dendriticadominates on trunks in older woodland. In the New Forest it is the only one on the trunks of the older and veteran trees, but yes further west Phaeographis smithiican also occur on trunks and stems and one does have to check where the thalli are not large and well developed. I would be very surprised if Phaeographis dendriticahad declined, but over recording in mixed populations is more possible I think, along with increases in the density of Phaeographis smithiipopulations. Neil
March 10, 2026 at 3:52 pm #46790I was sent an interesting specimen of Phaeographis dendritica by James Rowland, collected from a young Fraxinus in Aversley Wood in Huntingdonshire. Since this occurrence was so far out of its known geographical range James wanted to be sure of the identity. Everything seemed to fit, thallus K+ yellow turning red, ascospores turning pale brown when young-mature and dark excipular layer continuous beneath the hymenium. The one thing that disconcerted both of us was the septation of the spores, neither of us could find any with more than seven septa, while the published accounts state that the septation is (5-) 7- to 9- (10-)-septate. Brian has kindly confirmed the specimen as P. dendritica and provided the following note: “The majority of P. dendritica specimens I’ve seen have mainly 7-septate spores, so no worries there”. -
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