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Exciting Stuff in the Elan Valley

Posted: Wed Sep 11, 2019 10:35 pm
by Neil Sanderson
Last month I did a contract survey in the upper Elan valley for Natural Resources Wales. This produced one of the more intense bits of field work I have carried out with two lichens new to Wales and a refund of a species lost to Wales found in succession on three Oaks!

The site was Caban Lakeside SSSI, but the actual site was the upper part of Coed Gelynnen as left over from the flooding of the late 19th century reservoir. This wood was based on an ffrith pasture woodland and include some truly immense ancient Oaks at 260 – 300m altitude, so very high for an ancient Oak site. There had been some 19th C forestry activity and the wood was now little grazed but there were still some fantastic trees here.

I was already getting excited when I came across a particularly enormous Oak. This had a good bit of dry bark and lignum with the latter supporting a Chaenothecopsis sp (latter determined as Chaenothecopsis pusilla) and Chaenotheca chrysocephala. The bark also had an odd lichen with orange apothecia and a grey-white granulose thallus. This was odd, I dismissed Chrysothrix flavovirens apothecia (the wrong colour) and then noticed orange barrel shaped pycnidia. This rung a bell and I looked up a paper stored on my iPhone ... -113.2.333, YES! this must be Biatora ligni-mollis. This was the second British record of an intentionally scarce old growth dependant lichen and new to Wales. Interestingly the other British site, in east Sutherland, was also on a huge ancient Oak in an upland pasture woodland.


The tree with Biatora ligni-mollis

Biatora ligni-mollis, field picture using Lichen Candelaris/iPhone

Biatora ligni-mollis specimen, with pycnidia in centre

Top, Biatora ligni-mollis apothecia cross-section in water, howing the hyaline hypothecium & hymenium; middle an pycnida squash showing conidia, which area mostly ovoid (2 x 2.5µm) but with some bacilliform (5 x 1µm) conidia present & bottom spores 1 septate, 8–12 x 2–2.5µm

Cont. below

Re: Exciting Stuff in the Elan Valley

Posted: Wed Sep 11, 2019 10:50 pm
by Neil Sanderson
The next Oak produced small amount of a Calicium with a thick granulose yellowish thallus, I put this down as Calicium lenticulare, previously record from the site. Later a bigger spread of the same lichen, on another tree, brought home the yellowish colour of the thallus: Calicium lenticulare should have a granular greyish-green thallus. A quick dab of C gave a yellowish-orange spot test, definitely not Calicium lenticulare! This had to be Calicium hyperelloides, a widespread tropical species but recorded from Britain only in two locations, a single tree in the New Forest, which has subsequently fallen over, and several trees in Boconnoc Park Cornwall. Otherwise this species has only been recorded from Portugal in Europe. In the end I found it in 10 Oaks in this wood with this lichen. This was confirmed in the lab by the lack of a I + blue reaction of the stalk, a positive reaction is is definitive for Calicium lenticulare. In the field I found that Calicium hyperelloides has some good UV enhancements for the spot tests, the K + dirty yellow spot fluoresces bright yellow-green and the C + yellow-orange spot fluoresces bright yellow. The latter is the first useful C/UV test I have found.


The first tree with Calicium hyperelloides

A scan of a Calicium hyperelloides specimen

Closer view of Calicium hyperelloides showing the granular yellow thallus

Calicium lenticulare (Powerscourt Park, Co Wicklow), showing the grey-green thallus (ignore the pale Lepraria sp)

This is to look out for, at the recent Lake District BLS field recording meeting, Nichola showed me a recent specimen from Dartmoor, which also also clearly Calicium hyperelloides.

Continued below

Re: Exciting Stuff in the Elan Valley

Posted: Wed Sep 11, 2019 10:58 pm
by Neil Sanderson
The next Oak after the first Calicium hyperelloides tree then produced, not only Opegrapha fumosa, previously recorded from the site, but also a big spread of Tylophoron hibernicum (Blarneya hibernica) smothering Lecanactis abietina. This was remarkable, this extreme south western species had only been previously known from a single Oak in west Wales, which died a few years ago. Not at all what I expected at 260m in central Wales! Latter I found a second large colony, so this species is now a bit more secure in Wales.

Tylophoron hibernicum overgrowing Lecanactis abietina on the first tree

That was just three trees, there was a lot more of interest, but it did not come as fast or as stunning as this afterwards!