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Lichenicolous fungus on Lecania cyrtella?

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  • November 12, 2023 at 3:03 pm #32717
    Di N
    Participant

      On apothecia of Lecania cyrtella, on a twig of Sambucus nigra, from the same hedge as the Erythricium with basidia. Warwickshire

      Not sure these are distinct enough to be pycinidia, but the tiny brown circles on the Lecania discs are about 50 μm across. Conidia are 16-24 x 1.25-1.5 μm, curved and pointed both ends. The brown pigmented parts look somewhat like Intralichen, and similar hyphae are elsewhere in the apothecium.

      The conidia dimensions are similar to the description for Lecania cyrtella microconidia, though somewhat broader. But I wouldn’t have thought they would be produced from within an apothecium? LGBI3 mentions Epithamnolia sp under Lecania naegelii (a few 3-septate spores initially made that seem a possible host). It seems rather similar to ‘Hainesia sp. MP4706’ on fungi.myspecies

      November 13, 2023 at 1:47 pm #45742
      Mark Powell
      Participant

        I’m not sure I can help with the lichenicolous fungus but the host looks rather more like Lecania naegelii rather than L. cyrtella based on the appearance of the apothecia. The margins are rather conspicuous and the discs are becoming quite darkened, presumably due to pigmentation. The discs of L. cyrtella can vary a bit in depth of colour, from whitish pink to shades of pale brown but when I see the sort of mauve-grey colour seen in your specimen, I tend to think of L. naegelii. In my experience L. naegelii often has a considerable proportion of 1-septate spores even though the literature implies that they are mostly 3-septate in this species. Rather than use up infected apothecia, you could section one of the unaffected ones, as long as they appear to belong to the same lichen, and see if you can find any of the more typical relatively large and 3-septate spores of L. naegelii.

        Screenshot 2023-11-13 1.18.22 PM.png

        [attachment=0]Screenshot 2023-11-13 1.18.22 PM.png[/attachment]
        Although pycnidia are sometimes seen growing as part of the same structure as apothecia in lichen species, I have never seen pycnidia arising within the hymenium. I seem to remember seeing pycnidia within the exciple of Micarea erratica apothecia but that is one of the few examples that come to mind. In addition, and if I am correct that your host is L. naegelii, I don’t recall ever seeing the pycnidia of that species.

        I’m sorry I can’t provide anything more definite, just a strong suspicion that your host is L. naegelii and that the specks in the discs belong to a lichenicolous fungus. I can’t absolutely guarantee that I am right on either matter.

        November 13, 2023 at 7:51 pm #45743
        Di N
        Participant

          Thank you. Very helpful.

          Yes, I had already had a strong suspicion that the host might be Lecania naegelii, not L cyrtella, as I sectioned some more apothecia from the same source today, and found far more 3-septate spores, and some with more than three septa, and most were 20 um or more long, although a few were shorter and with only one septum. I presume that the previous spores were immature (perhaps affected by the infection).

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