aspeca
Forum Replies Created
-
Many thanks for starting this forum topic, Mark. Last month I found ostensibly the same mould-like anamorphic conidial fungus in a specimen of
Lecanora hybocarpafrom near Lavenham, Suffolk (VC26/TL921498). The thallus is on I think a Corylustwig — the twig was broken and could have come from another tree, but it was well caught in a hazel at the edge of an arable field, and most of the surrounding trees seemed to be hazel. As with Mark’s specimen, the LF shows up as a red staining and ‘rotting’ in the apothecia. It doesn’t seem to affect the thalline margins or the thallus more generally.
[attachment=9]20231005-PA050262.jpg[/attachment] Even apothecia that seem relatively unblemished are affected. In this section, mounted in water in cross-polarised light, a reddish stain appears within the hymenium. The LF seems to have inhibited or degraded the normal development of the apothecium. The descending POL+ epithecial granules characteristic of
L. hybocarpaare missing, except in the ‘healthy’ part of the apothecium. Asci with spores are visible, but again only in the healthier part. Where the reddish stain is present, there seem to be no asci at all. The LF seems to have inhibited or destroyed them as well. 
[attachment=8]20231005-PA050265.jpg[/attachment] An overview section of a visibly fully parasitised apothecium, again mounted in water, shows that the reddish stain of the LF dominates the fruiting body. No asci are seen at all (nor POL+ epithecial granules, not shown here due to the limit on the number of photos per post).
[attachment=7]20231005-PA050268.jpg[/attachment] However, the LF’s hyaline conidia can be made out peeping about the surface of the apothecium (a different apothecium than the one above). As with Mark’s specimen, the conidia are 1-septate (1 div = 1 µm).
[attachment=6]20231110-PB100790.jpg[/attachment] Clearing and staining in K-ink-vinegar brings out the LF’s hyphal network. Again, the LF appears confined to the hymenium of host apothecia, seemingly drawing its nutrients from the hymenial tissue, not the photobiont. Clearing and staining also make obvious that the host’s asci and paraphyses are nearly entirely inhibited or degraded or destroyed. Essentially only the LF’s own hyphae remain (1 div = 10 µm).
[attachment=5]20231110-PB100793.jpg[/attachment] The LF’s hyphae appear mostly to be trending towards the surface of the host apothecium to sporulate. Developing conidia and perhaps also phialides are visible near the 5 to 8 marks on the scale (1 div = 2.5 µm).
[attachment=4]20231110-PB100797.jpg[/attachment] The hyphae themselves are hyaline as the unstained images above show. They seem to be roughly 3-4 µm wide, including a roughly 0.5 µm cell wall. It’s hard to get a sense of the length of each hyphal cell, as the hyphae seem to twist. They don’t seem to branch too much, though (1 div = 1 µm).
[attachment=3]20231110-PB100800.jpg[/attachment] A close look at free and developing conidia shows that fully mature spores are roughly 13-16 µm in length and 4-5 µm in width, including a roughly 0.5 µm cell wall — in line with the size of the conidia in Mark’s specimen (1 div = 1 µm).
[attachment=2]20231110-PB100803.jpg[/attachment] 
[attachment=1]20231110-PB100806.jpg[/attachment] 
[attachment=0]20231110-PB100809.jpg[/attachment] Apart from this thallus, there are other
L. hybocarpathalli from the same twig that appear to be similarly infected. I also have a more recently collected L. hybocarpaspecimen from near Glandford, Norfolk (VC27/TG037408) that I think might also host this LF. Many thanks, Paul, for your suggestion of
Acremonium pedatum/ Pronectria anisospora. Acremoniumhas come up in the Twitter discussion, which has also brought forward additional finds that others may wish to post here. Grateful for any further advice about next steps towards identifying or describing this LF.
Many thanks, Alain — that’s very helpful. It’s interesting that you think the lichen may be a cryptic taxon within the broader conception of H. maura s. lat.I hope you’re able to recommence your study of Hydropunctaria. I wonder if
H. oraecan be completely discounted? [list][*]The image is from the interior of the thallus, so the prothallus wouldn’t be visible. I don’t particularly remember a white prothallus, but as I was unaware ofH. oraeat the time, I wouldn’t have looked for it specifically. [*]Alan Orange does indeed mention that H. orae likes freshwater, but he says it can be found ‘especially where slightly irrigated by rainwater’. The Scottish coast on which I found this specimen is extremely rainy, and that location might have been ‘slightly irrigated’ by rainwater fairly regularly. I don’t really remember it as a rainwater channel — but again I wasn’t looking specifically.[*]The colour in the image could easily be an artefact of the camera. When I reduce the colour temperature even slightly, it looks yet greener to me (see below). But I suppose it’s hard to say.[*]The thin patches in the thallus, and the limited cracking even in the thicker parts, seems more like Alan Orange’s description ofH. oraethan anything else — especially considering that he says of H. maurathat ‘The thallus is always well-developed and cracked into mostly discrete areoles’. But that doesn’t rule out another cryptic taxon apart from H. orae. [/list] 
[attachment=0]20230807-P8070802-2.jpg[/attachment] As for
H. oceanica— yes, the reason I downplayed that possibility below was that the perithecia didn’t seem pointed in the way you suggest, and as shown in Alan Orange’s pictures. In any case, it seems perhaps that the image (regrettably the only one, as I took it uncontroversially to be
H. maura) doesn’t suggest H. oraeor another known Hydropunctaria taxon clearly enough to follow up. Perhaps I’ll return there next summer! Thanks again for your help.
Following on the post above — on the same large twig there were many other similar Lecanora chlarotera-type thalli. 
[attachment=4]20230317-P1130729.jpg[/attachment]
I examined the thallus at the bottom of the photo here in an attempt to ascertain whether it might also beLecanora hybocarpa. It shows the flat-to-concave, more dispersed pink-brown apothecia mentioned in LGBI3 (as well as perhaps some apothecial initials characteristic of L. sinuosa? — which LGBI3 suggests might actually be the correct taxon for at least some European forms of L. hybocarpa). 
[attachment=3]20230326-P3260652.jpg[/attachment]
K+ yellow as expected, but less convincingly as the earlier thallus above (perhaps I hadn’t scratched the cortex properly, but for some reason I didn’t try again).
[attachment=2]20230326-P3260660.jpg[/attachment]
An overview of an apothecial section in cross-polarised light — and what seems to be a much more central section this time! The polarisation arrangement was the same as with the thallus above. This section shows the expected large crystals in the thalline margin, and perhaps some characteristic descending epithecial granules.
[attachment=1]20230326-P3260669.jpg[/attachment]
Another apothecial section (more or less from the centre) in brightfield.
[attachment=0]20230326-P3260668.jpg[/attachment]
The same section as above in cross-polarised light.Any advice welcome on this thallus, as well as the one above!
Thank you,
Anthony
