What is Sphinctrina tubiformis Parasitising, one of my Lockdown Projects

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Neil Sanderson
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What is Sphinctrina tubiformis Parasitising, one of my Lockdown Projects

Post by Neil Sanderson » Sat May 16, 2020 1:34 pm

One product of the lockdown and me walking daily the local woods and dealing with backlogs of records is one getting the measure of finding the rare crust Pertusaria pustulata and also working out that the host of the very rare Sphinctrina tubiformis is not the common Pertusaria leioplaca as was thought, at least in the New Forest.

Pertusaria pustulata is a sub-oceanic Beech specialist, which I have found on Beech and Holly in the New Forest, Hampshire and Ebernoe Common, West Sussex. It appears to be occasional but widespread in the New Forest. There are few other records but it is probably being overlooked. It has been recorded from Oak and Ash, habitats on which I may be over looking the species myself. It looks very similar to Pertusaria leioplaca but has a subtile jizz. The opening to the fertile wart widens with age, becoming raged and torn, with a black disk showing. In contrast in Pertusaria leioplaca, the disc is narrowly exposed in a punctiform, ostiole-like opening. This is a hint but not that reliable, to prove Pertusaria pustulata the asci need to be examined. These have only two rather beautiful spores (typically 80 - 125µm long). Pertusaria leioplaca has 4 spores per ascus, which are smaller (typically 50 - 80 µm long). A good tip is that the spores and asci are so big that thick sections are need or you will cut up the acsi. There is however, a good spot test difference in the field in that both Pertusaria pertusa and Pertusaria leioplaca are K + yellow but C -, while Pertusaria pustulata has both K + yellow and C + yellow spot tests. The C + yellow reaction is patch and can be absent in parts of the thallus, it is mostly seen on the fertile warts. Pertusaria hymenea looks different and is C + yellow but K -.

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A nice big spread of Pertusaria pustulata on the base of an old Beech, Plian Green, Busketts area, New Forest.

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A close up of typically obscure material of Pertusaria pustulata, very like Pertusaria leioplaca on Beech, but the exposed dark disks are a tell, Plain Green.

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A striking wet thallus of Pertusaria pustulata on Holly, east of Millyford Bridge, New Forest

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Asci of Pertusaria pustulata showing the two spores per asci, Beech, Matley Wood, New Forest

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A spore of Pertusaria pustulata, lovely things with an ornamented spore wall, Beech, Anses Wood, New Forest

Further pictures, including the spot tests, at http://www.lichensmaritimes.org/index.p ... 28&lang=en

In recent my lockdown wonderings around my local Beech woods I was getting a much better eye in for this species and I was finding that there was lot more of it was about than I had realised on the old Beech and Hollies. I then began wondering about the very rare parasite Sphinctrina tubiformis, a short stocked pin head parasitic on Pertusaria species. Unlike the more widespread, but still uncommon Sphinctrina turbinata mainly found Pertusaria pertusa, Sphinctrina tubiformis is supposed to be confined to Pertusaria leioplaca on trees. (It is also recorded on Pertusaria pseudocorallina on rock in the west, but if the pictures in the Lichens Marins website http://www.lichensmaritimes.org ... 88&lang=en named Sphinctrina tubiformis and shown parasitising Pertusaria pseudocorallina is the same taxa as recorded in Britain on Pertusaria pseudocorallina, then it is certainly not Sphinctrina tubiformis. This dark, apparently distinctly stalked and clustered licheicolous fungi looks nothing like the New Forest Sphinctrina tubiformis on trees). Sphinctrina tubiformis had first been recorded in Britain from the New Forest from “near Brockenhurst” by the Rev. Crombie in 1869 and not seen again until Andy Cross and I rediscovered it parasitising a big spread of Pertusaria midway up the fallen Beech in New Forest in 2010, at Coomy Hat, Busketts Wood, on which we recorded systematically and found 68 lichens and lichenicolous fungi. I have since found it at two nearby sites in this area (the Busketts Wood area) and recently found it in Mark Ash Wood. Barbara Benfield has had it once in Devon. Extraordinarily rare for a supposed parasite of the common Pertusaria leioplaca.

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Sphinctrina tubiformis parasitising a Pertusaria on Beech, Mark Ash Wood, New Forest, the host is badly suppressed and not easily identified

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Sphinctrina tubiformis parasitising a Pertusaria on Beech, Mark Ash Wood, New Forest, here stalkless but it can have a short stalk

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Sphinctrina tubiformis parasitising a Pertusaria on Beech, Mark Ash Wood, New Forest, the distinctive ellipsoid spores

We wrote up this discovery in the BLS Bulletin https://www.researchgate.net/publicatio ... _Hampshire and I was reminded of this in a recent conversation on the lichen list server. In this exchange I learned that we had unknowingly recorded a very rich tree for temperate woodland and one that would be respectable in a tropical rainforest. Not a patch on the record number, however, Andre Aptroot’s 172 taxa from a tropical rainforest tree in South America! This set me thinking what exactly was Sphinctrina tubiformis parasitising, was it actually Pertusaria leioplaca? Sphinctrina tubiformis depresses the growth of the lichen, so it is not actually all that recognisable. Looking at my pictures with my newly improved Pertusaria pustulata search image it really looked rather more like Pertusaria pustulata than Pertusaria leioplaca. So I got out the Mark Ash Wood specimen and put a little C on a poorly developed apothecial wart on the edge where the Sphinctrina damage was less, yes a tiny patch of C + yellow, so not Pertusaria leioplaca. This was not completely convincing, it was a tiny area of thallus that reacted, so I sectioned another partially surviving apothecial wart. It was a bit poor inside with a lot of empty asci and some malformed spores, but yes there were some healthy asci with two spores of the correct size. So on this specimen the Sphinctrina tubiformis was parasitising Pertusaria pustulata not Pertusaria leioplaca. The original Coomy Hat specimen is now in the Natural History museum, so out of bounds at the moment, but I took a couple of the dogs out for an evening walk to the second site, and yes the parasitised Pertusaria was giving a clear C + yellow reaction, and the unparasitised adjacent material was clearly Pertusaria pustulata. Of the others the third Busketts Wood site had a large spread of Pertusaria pustulata on the neighbouring Beech tree when found and the photos of the original find on the fallen tree were also obviously also Pertusaria pustulata. So I am know convinced that all modern records of Sphinctrina tubiformis from the New Forest were of material parasitising Pertusaria pustulata.

This would certainly explain its rarity in the New Forest, Pertusaria pustulata is assessed as Vulnerable in the current Red List. This conclusion leaves much more work to do. Sphinctrina tubiformis has a wide distribution in western Europe and the rest of the world, where the literature, always gives Pertusaria leioplaca as the preferred host on trees; is it really? Is the odd looking thing on Pertusaria pseudocorallina in Brittany, the same as has been recorded on Pertusaria pseudocorallina in western Britain, if so what is it? The Brittany fungus does not appear to be Sphinctrina tubiformis. This is an important point, because if it is not Sphinctrina tubiformis, then Sphinctrina tubiformis would also at least Vulnerable in a new Red List, potentially Endangered.

Keep safe

Neil
Neil Sanderson

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