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Becky: It’s on the radar, but even with molecular data it’s still a mess. I’m hoping that as we sequence more collections, some well defined groups will emerge.This collection with a thick thallus is so obviously not P. macrocarpa s. str. that it deserves further investigation.
Alan
Looks OK to me Chris. I now recognize this taxon at the species level. It would be good to get sequence data from this specimen if Becky is agreeable… Looks good to me as well. I was a bit concerned with the UV+ orange reaction as there’s nothing in the chemical profile of this species that should give that reaction. However, I’ve just put some collections of
M. leucophaeaeunder UV and they mostly had a UV+ yellow reaction of varying intensity. This is probably due to the presence of carotenoids, which don’t show up in regular TLC. Alan
Hi Rob (& Neil and Paul): Apologies for my late response. I’m blocked from posting to this forum from my home network so have to wait until I go into the herbarium.
Haugania oederiand S. intrusumare both good suggestions but I don’t think it is either of those – H. oederiwould have gyrose apothecia and a dark hypothecium, and I have only ever seen S. intrusumwith 0–1-septate spores. The apothecial section has the look of a
Micareaand I rather suspect this is M. lignaria. Although that species usually has mutiseptate spores, it can also have 3-septate ones. I have collected such a specimen in Scotland and it had me fooled as well! An alternative, left-field, suggestion would be a lichenicolous
Arthoniain the hymenium of Lecidella stigmatea. It doesn’t look like A. intexta, but I’m sure there are others. Cheers – Alan
Looks more like Rehmia reductaaggr. to me (? R. postuma). Rehmia umbilicatahas a well-developed thallus and innate apothecia with a grey prinose margin. The limestone substrate is unusual, but I have seen this species on calcareous sandstone. I suspect the ‘soredia’ are just free-living algae. Note that the
Rh. reductumgroup is now recogonized as the distinct genus Rehmia. For this and other changes see: https://fuse-journal.org/images/Issues/FuseVol16Art12.pdf Alan
The C+ orange reaction indicates xanthones and suggests Lecidella of Lecanora s. lat., but the PD+ red (?fumarprotocetraric acid) is unusual and rules out most possibilities. Could it be a really weird L. meiococca, which reportedly sometimes grows on ‘decaying Armeria tufts’ and can have a variable chemistry. Martin: All that you say is very true. Morphology suggests R, saanaense bur spores and habitat suggest R. macrosporum.
As I said, I don’t know R. saanaense at all, and have collected R. macrosporum only rarely. You might want to post your photos to the Facebook group ‘Lichens Connecting People’. Einar Timdal is a member of that group and has a much better understanding of these species than I do.
Best of luck – Alan.
Hello Martin Rhizocarpon saanaënseis not a species I know – it is not known to occur in the UK and I have never knowingly collected it elsewhere. However, from your description, the only other species it could be is R. macrosporum– and from the spore size given by McCune (2017), which is the best current guide to the yellow Rhizocarponspecies, that species is the more likely ( R. saanaënse25–40 x 12-17 µm, R. macrosporum(32-) 42-54(-60) x 15-22 µm). R. saanaënseis also said to have only rhizocarpic acid or an additional unknown substance, whereas a stictic acid (K+ yellow) chemotype of R. macrosporumdoes occur. You say it was growing on ‘green slate, but was it acidic or slightly calcareous? R. saanaënseis a species of calcareous rocks, whereas R. macrosporumoccurs only on acidic rocks. Hope this helps – Alan
Hi Jenny: Definitely not
L. radiatum, which has spreading, elongate lobes. Perhaps L botryosum, but I don’t know Lichinalesat all well. Alan
Looks OK to me, John. Nice one! The photo on the cover of LGB3 40 is of an exceptionally well developed specimen – most are a lot more like your collection. I was wrong! Oh well. Not the first time. I’ll be interested to see where this fits into our big porpidioid phylogeny.
