Xanthoria sp ??

[kiltoncomp]

i found this one on a dead elder bush at the edge of a field in a sunny position, there were lots of them all over the branches in patches like this one,

i have narrowed it down to possibly Xanthoria polycarpa or parietina,
or then again, is it something else
is there any way to differentiate between the two ?? or is it a microscope job?

thanks,
Brian.

[CapAndBracket]

From the image i would think Xanthoria polycarpa, but microscopy is the
definative. seeing rather a lot of lichen on trees at the moment looking very
dry and shriveled, but i'm sure as soon as there is rain they will look healthy
again, know little about them but marvel at their ability to survive.

Cheers J.P.

[JennyS]

From the look of the lobes I'd say its X. parietina - if you compare the two images below from AlanS's site you'll see the difference even though the lobes on yours are very small and pretty much hidden by the apothecia:

Xanthoria parietina (images of British lichens)

Xanthoria polycarpa (images of British lichens)

[kiltoncomp]

Thanks JP & Jennys for your comments,

I was swayed to X.polycarpa due to its size and the way it was growing in the axils of the (thin)twigs it was on, (as described on AlanS's excellent site)as were the several dozen other specimens of it on the same bush
The specimens of X.parietina I have found have always been on oak trees on much more substantial branches, giving the impression of much larger specimens, I had wondered if being on these small thin twigs that they were just adapting to the twigs smaller surface area instead of the more usual rosette shape , (the X,parietina specimens I found on oak were all of a larger rosette shape)
But as Jennys points out, the lobes look right for X.parietina

Many thanks for your invaluable help in a subject I know very little about as yet,

( I was out in the Pleasley area of notts today, and was amazed at the quantity of lichens growing on the hedgerows, and trees , mostly of the same species, which looked like the specimens above, but also one on top of a stone wall that was orange in colour like these but more crust like in appearance, I will post a pic as soon as I get time to transfer the pics to computer,)

Brian,

[kiltoncomp]

Originally Posted by kiltoncomp

( I was out in the Pleasley area of notts today, and was amazed at the quantity of lichens growing on the hedgerows, and trees , mostly of the same species, which looked like the specimens above, but also one on top of a stone wall that was orange in colour like these but more crust like in appearance, I will post a pic as soon as I get time to transfer the pics to computer,)

Brian,

these are the pics of the one on the stone wall, i assume that they are the same species ,Xanthoria parietina ,as the ones on the twigs ??


Brian.

[RobSutton]

Can I add another Xanthoria for help - as with Brian I came down to a choice between X.parietina and X.polycarpa and until I read this thread was coming down on the side of polycarpa on the basis of habitat (in the armpit of a hawthorn twig) and largely obscured thallus but now I'm not so sure.



Any suggestions? And what do you look for microscopically? - there seems to be a lack of easily accessible info about microscopic preparation and examination of lichens.

Thanks

[JennyS]

Hi Brian, yes the new photo's are X. parientia too.

Hi Rob, ooh aah eee, ones like this really throw me!
I'd still reckon X. parientia though I wouldn't be as sure as I was with the first one Brian posted..... the lobe at the top left of the pic is definitely X. parientia but the two species can grow together.
Sorry, not too much help on this one!

[kiltoncomp]

Originally Posted by JennyS

Hi Brian, yes the new photo's are X. parientia too.

Hi Rob, ooh aah eee, ones like this really throw me!
I'd still reckon X. parientia though I wouldn't be as sure as I was with the first one Brian posted..... the lobe at the top left of the pic is definitely X. parientia but the two species can grow together.
Sorry, not too much help on this one!

thanks for the confirmation Jenny, this one was more like the ones i found on the oak trees, being much larger and of a spreading habit,

Rob, if its of any help, there were a few like these(almost covered in the disc shaped apotheica (hope ive got that right!)) on the elder bush i found the first ones on, which i assumed were all the same species,
but Jennys saying the two can grow together has put a new outlook on things,
and there was me thinking that lichens were much easier to id than the usual fungi

Brian.

[RobSutton]

Thanks Jenny & Brian - I've always steered well clear of lichens, apart from one or two really distinctive species, but this was such a nice looking specimen I thought I'd have a go at identifying it properly. Having similar species growing together just makes it even more difficult - oh well back to the mosses until the next flush of fungi.

[AlanS]

I agree with Jenny that everything posted in this thread is Xanthoria parietina, but this thread well illustrates the difficulty at times of separating the two species.

Microscopically, X. parietina is said to have longer conidia (obtained by a squash of a pycnidium, an orange pimple in the thallus surface), 2.7-3.6 μm in X. parietina, 2.2-2.9 μm in X. polycarpa, but these figures are from an American source (Lindblom, 1997) and I don't know how well they apply to British/European material.

Alan