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Thelotrema lueckingii everywhere

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  • August 31, 2024 at 4:44 pm #32865
    SylviaD
    Participant

      Spurred on by a recent post from Pete Martin about the Graphidaceae workshop about Thelotrema lueckingii, I decided to visit Eridge Rocks SWT reserve in Sussex where I always assumed I was seeing Thelotrema lepadinium. Tested Thelotrema on six trees that I could get to and all gave a yellow/orange/brown reaction to KOH indicative of T. lueckingii – before and after photo attached of a sample I brought home.

      Is this K reaction sufficient to confirm T. lueckingii?

      Thank you

      Sylvia

      September 3, 2024 at 1:21 pm #46170
      petemartin
      Participant

        That’s my understanding. Ihe medulla should look yellowish too.

        I haven’t seen a lot of Thelotrema since the course, but that I have has all been lueckingii so far ( Cumbria/ Dumfries).

        Pete

        September 3, 2024 at 7:46 pm #46171
        SylviaD
        Participant

          Thanks Pete,

          That’s what I thought but I was rather taken aback when the Thelotrema on every tree I tested went K+ orange. Well this is going to call for a bit of alteration to my records. Only one site done so far, it’ll be interesting in other areas where I’ve found Thelotrema.

          Best wishes,

          Sylvia

          September 4, 2024 at 9:21 am #46172
          Paul Cannon
          Participant

            I find this interesting too – we know that T. lueckingii is widespread but still don’t have much clue as to its overall distribution. However, I’ve read elsewhere on this site (if my memory serves me correctly) that the K+ brown reaction is rather unspecific, and I would prefer to identify the species by sectioning the apothecial warts to see the yellow coloration underneath.

            I’ve done a species page for T. lueckingii – see https://fungi.myspecies.info/all-fungi/thelotrema-lueckingii” class=”bbcode_url”>https://fungi.myspecies.info/all-fungi/thelotrema-lueckingii – the yellow pigmentation varies in intensity so look at all the images using the “media” tab.

            That’s assuming that the site is accessible – we have been having yet more problems with accessibility. Feedback on your user experience will be appreciated!

            Best wishes

            Paul

            September 4, 2024 at 9:40 am #46173
            SylviaD
            Participant

              Many thanks Paul,

              I have brought a few samples back and will get sectioning and see what I find. I am really intrigued now as to how the two Thelotremas are distributed. I managed to see the media files OK, but I have had a few issues over previous days/weeks – the occasional error message and having to reload to get to a page, but never not being able to access it at all, which happened a while back.

              Best wishes,

              Sylvia

              September 5, 2024 at 1:41 pm #46174
              SylviaD
              Participant

                Hi,

                I did sections from four samples (four Oak trees). Photos are attached. The yellow was even more obvious in real life, in some of the medulla there was a very intense yellow, in other places a more mellow and buttery yellow, something impossible to capture with a photo. There was also variability within the same sample. These were all from Eridge Rocks near Tonbridge Wells, so almost in Kent, which is quite far east. It’s ancient woodland that is fairly humid.

                I don’t think T Lueckingii has been recorded before in Sussex.

                Thanks for your help,

                Best wishes,

                Sylvia

                September 5, 2024 at 4:50 pm #46175
                Paul Cannon
                Participant

                  Certainly looks good to me. It has to be said that to my knowledge, T. lueckingii hasn’t been sequenced so we don’t know what the significance of the colour change is in phylogenetic terms (or what chemical produces the colour).

                  Good wishes

                  Paul

                  September 5, 2024 at 6:11 pm #46176
                  Di N
                  Participant

                    Out of curiosity, I just looked at the (only) three samples of Thelotrema that I have, all from Wales (around Dolgellau), and all three have distinct yellow pigment within the apothecia, that goes brownish with K, though the K reaction wasn’t pronounced.

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