Saturday, 23 March 2013

More on the Exciting New Lichens in Sussex

Teloschistes chrysophthalmus - the Tangerine
Mark Jackson who lives in Southampton should be crowned the Teloschistes chrysophthalmus King. Recently, I received an e-mail from him saying that he had found eight bushes with Teloschistes to the north east of Brighton, and another two not too far from where he originally found it. Inspired by this news, I went over to have a look at areas between Birling Gap and Beachy Head where there were masses of thorn bushes in open country that seemed ideal. I was utterly convinced I would be successful, but in the event, I failed to find any. Having never ever actually seen Teloschistes chrysophthalmus without being shown it, I resolved to go and have a look at one of Mark’s sites for which I had very accurate grid references. In spite of this, it took me some time to find his two bushes with it on.

The bush supporting the impressive Teloschistes chrysopthalmus - the
'Tangerine', which can just be seen half way up on the left of the bush
The two bushes with Teloschistes in this case were distorted by fierce, no doubt salt laden winds. The sea could be seen in the distance. On one of the bushes the associated lichen flora was far from rich, the twigs being golden, dominated almost exclusively by Xanthoria parietina. On the other bush, where the Teloschistes was one of the most beautiful examples I have yet seen, in a tiny area the lichen assemblage was rich and contained all the usual associates. The lichen itself looked like a tangerine that had been pushed onto the spiky hawthorn twig.

Illosporiopsis christiansenii, parasitic fungus on Physcia tenella
Physcia tenella
Remembering that in the first two sites where I had seen Teloschistes recently I had also found Physcia tenella infected by the pink parasite Illosporiopsis christiansenii, it occurred to me that I had never seen Teloschistes without the association of Physcia tenella. It was while I was hunting for Teloschistes around Birling Gap that it occurred to me that this association might be the case. There was plenty of Physcia adscendens on the bushes, but I completely failed to find any Physcia tenella. It was an e-mail from Janet Simkin, lichenologist responsible for all computerised lichen records that underlined my thinking. She had suggested that there might be a link between Physcia tenella and Teloschistes as she had seen Physcia tenella and Xanthoria parietina in parasitic competition, with neither species apparently getting the upper hand. In these two species the lichen fungus is associated with the same algal partner, which is also the same as that of Teloschistes chrysophthalmus. Could it be that Teloschistes required to parasitise Physcia tenella in order to get started. The lichen Diploschistes muscorum inevitably requires to parasitise material of a Cladonia, usually Cladonia pocillum before it can become established as a free living entity.

Although Teloschistes chrysophthalmus does appear to be appearing ever increasingly in Southern and South-eastern England, its occurrence still seems to be patchy. It will be most interesting to continue to discover the parameters and associated species with which it appears. Cattle are frequent on the grassland around Beachy Head but the field behind us, and in the places I have recently seen Teloschistes are used as horse pasture. This observation is far from conclusive, but is one that seems to be worth considering. Certainly the smell of cattle urine in areas used intensively for their pasture can be overwhelming. The smell of horse is quite different. It seems possible that there might be a link.

Not far away from where we live, there is a church with a north wall covered in an ancient plaster giving ideal conditions for a rich lichen flora. Recently my wife and I visited it in the hope of finding that other newly recorded Sussex lichen Llimonaea sorediata. I must apologise here for the wrong spelling in my previously blog where I called it Llimonia. I was delighted to see large areas of the north wall were covered in pink, and this confirmed the first record of the species for East Sussex VC 14. It was a bitterly cold day, but the churchyard was surrounded with hawthorn and blackthorn bushes festooned with a healthy and varied lichen flora of just the sort that Teloschistes is associated with. A northerly wind made eyes water, and observation difficult. I was convinced I was going to find the first churchyard record for Teloschistes, but our suffering was to no avail. At that point, I had not thought about the possibility of an association with Physcia tenella, so I will have to go back and see if I can find it there.

Looking out of the window as I wrote the first part of this, the view was dominated by blizzard conditions. The chances of driving up minor roads lined with the sort of isolated hawthorn and blackthorn bushes of the Sussex downland were worse than remote. With a bit of luck, spring is just around the corner, but soon after any improvement, leaves will festoon suitable bushes making Teloschistes observation much more difficult.

Since writing this, a field meeting has taken place in Hampshire where Mark Jackson, now the undisputed Teloschistes King was able to show others a further eleven bushes with Teloschistes in another five new locations. It does seem that the wonderful Goldeneyes lichen is becoming a new, and very welcome aspect of our lichen flora. The reasons for its sudden appearance still seem to remain something of a mystery.

1 comment:

  1. Dear Simon,

    The use by X. parietina of the algae in one of the ciliate Physcia species was first documented by Sieglinde Ott (in 1988, I think, but I don't have her paper in front of me right now). The phenomenon is rarely mentioned in print, and one eminent lichenologist has questioned whether this phenomenon is real, though I don't think he has published his view. I'm sure it is real, as I remember seeing it myself many years ago, though I didn't collect the material. If you and/or Janet keep coming across good examples in the UK, then it might be worth taking some photos and publishing a paper. (I can give you the reference to Ott's paper if you need it.)

    With best wishes,

    Linda in Arcadia