Odd Micarea from my First Social Distancing Lichen Trip

[Neil Sanderson]

Last Friday afternoon I had my first experience of lichening in the shadow of the carona virus. I went for a walk on the New Forest with Andy Cross and one of my dogs. Walking at least two meters apart and pointing and stepping away from interesting finds.

We went to Wormstall Wood in the south of Beaulieu Heath West. This is a small but rather different old growth pasture woodland, with Oak dominant over old Hazel and little Holly. It is also the only New Forest Ancient and Ornamental wood in 10km OS grid square SZ39, and, until this year, had not been looked at much since the 1990s, so need a visit to update the BLS maps. The wood is bit of away from any car parking and I already had a go from the east in February, when I had added Bacidia incompta, Porina hibernica and Arthonia invadens to the 10km square list. This time we walked in from the west. This was another successful trip with Arthonia zwackhii, parasitising Phlyctis argena, on both Oak and Maple, new to the square and a small non-soredate Syncesia myrticola thallus without any soralia and with developing stroma found. The non-sorediate morph is normally very coastal and mostly found on rock and was new to Hampshire. The sorediate morph (Enterographa sorediata) was abundant on the old Oaks. We also found more Porina hibernica and refound Lecanora alboflavida and Parmotrema crinitum for SZ39. Only Agonimia octospora is left of the rare species to refind for SZ39.

We did also find one very odd Micarea, which I will described here incase anyone can identify it:

Thallus grey-green, crustose, C –; photobiont cells 4 – 5µm diam, clumped in the thallus; no apothecia; doliiform (barrel shaped) pycnidia, some short stalked and supporting two or more pycnidia, 0.25mm diameter, pycnidia walls straw coloured, K + darkening, C –, tipped by whitish masses of macroconidia so appearing tomentose but not; with macroconidia 30 – 38 x 1µm curved. The thallus and macropycnidia suggest Micarea peliocarpa, but the doliiform to short stalked pycnidia and the C – reactions do not; so I have no idea, does anyone?

Micarea with short stalked doliiform pycnidia, with two pycnidia on each stalk.

Micarea with doliiform pycnidia, masses of Macroconidia spilling out of some

Doliiform pycnidia in water above; in K below

Macroconidia

Keep safe it is going to be a rough few weeks

Neil

[Mark Powell]

Hi Neil,
Have you considered Fellhaneropsis vezdae? That is just a suggestion off the top of my head at the moment but it might be one to check; most of the characters seem to fit fairly well.
Mark

[Neil Sanderson]

Mark

Ah yes you are probably right, in the sterile key I followed 31 at couplet 30. My algal cells were cells 4 – 5µm diam and globose:

30(1) Photobiont micareoid, cells 4-7 μm, ± globose, thin-walled ......................................................... 31
Photobiont chlorococcoid, cells mostly >8 μm diam. .................................................................... 41

If I go with 41, then yes I end up at Fellhaneropsis vezdae, where the algal cells are stated to be:

photobiont cells 4-7 μm diam.

in the full description.

So it is a bit difficult to actually get to Fellhaneropsis vezdae in this key!

The short stalked pycnidia supporting two or more individual pycnidia seem a bit unusual to me, but presumably just a well grown thallus?

I have not seen Fellhaneropsis vezdae on the New Forest for some time and there are few post 2000 record for all of Britain but many pre-2000 records. Recorder bias or declining with de-acidification?

Fellhaneropsis vezdae distibution Jan 2019

Thanks

Neil

[Mark Powell]

I remember Brian describing Fellhaneropsis vezdae as a species that has 'gone out of fashion'. I suspect that your suggestion of a decline due to de-acidification is highly likely. Sterile F. vezdae was one of the first 'mysteries' that I came across in my early days (2008). Then I found fertile thalli very occasionally on ash trunks while working in woods in the late noughties. Although inconspicuous, I would readily recognise candidates for it on sight and I have only seen it once in the last decade.

It is useful that this has highlighted the issue in the sterile key.

Micarea nitschkeana on twigs and Scoliciosporum pruinosum are other lichens that have 'gone out of fashion' across much of lowland England at least. Also Amandinea punctata, Scoliciosporum chlorococcum and Xanthoria polycarpa are much declined on twigs (partially replaced by Catillaria nigroclavata and Halecania viridescens). There are rapid changes and there is much that lichenologists can do even if they have to stay local in the current coronavirus circumstances.

[janetsimkin]

The number of records in the database by decade, shows the decline nicely.

[Neil Sanderson]

Interesting, certainly the case with some, although in the case of Scoliciosporum pruinosum, I think recent under recording might be a factor in Hampshire, we will see with the revived Hampshire lichen survey. Andy and I refound it in SU61 in a large wood in the Hampshire Basin, recently, but perhaps it might be gone from smaller woods on the chalk?

Neil