Unknown Orange/Yellow Lichen.

artysen · #1 (**permalink**) 16-05-2009, 09:48 AM

Hi Folks,

My first forum post so I thought I'd say hello. Need help to try and identify this lichen.

It's a bright yellow/orange, very dry and powdery but quite hard. I've tried doing some research and think it may be Mustard Powder lichen or Gold Dust lichen, Chrysothrix candelaris. That seems to be the closest to it, but not 100% sure. Any help would be appreciated.

JennyS · #2 (**permalink**) 16-05-2009, 07:09 PM

Hi artysen, what was this growing on - wood, rock etc?

artysen · #3 (**permalink**) 17-05-2009, 08:56 AM

Hi JennyS,

Thanks for getting back to me. It's growing on a tree, I've included an image of it below. I'm afraid I'm a bit new to all this, so wouldn't be able to tell you what species.

There is quite a bit of it on the bark and on another tree just to the left and a bit further back in the photo.

Lancashire Lad · #4 (**permalink**) 17-05-2009, 04:09 PM

Hi artysen,

I think your photo shows an alga, one of the Trentepohlia species.
It is very common on tree trunks, (usually concentrated on one side of the trunk), in large expanses similar to that shown in your second pic.
Regards
Mike.

AlanS · #5 (**permalink**) 17-05-2009, 08:35 PM

Hello Artysan

Welcome to the Forum.

I agree with Mike that this is a Trentepohlia, officially a green alga but full of orange pigment that is assumed to be a protection against strong light. Consequently it is able to be more exposed than most green algae.

Trentepohlia species have spread rapidly in Britain in recent years - it is suggested that this is a climatic warming effect, since Trentepohlia is a largely tropical genus. This one that forms a very firm crust seems to be a recent phenomenon - I am not sure that it is one of the species listed in the British algal flora but I have not looked at myself in detail. The usual species on trees is T. abietina, but that forms a thin "fluff".

If it was a lichen it would be a Caloplaca of the C. citrina group (i.e. not one of the soft, powdery Chrysothrix species), but the surface doesn't really look right for any individual member of that group.

The annoying thing with photographs is that we cannot put a sample under a microscope, but lacking that facility, I have to go with Mike on this.

Alan

artysen · #6 (**permalink**) 17-05-2009, 10:59 PM

Hi Mike, Hi Alan,

Thanks for your replies.

I did a search on what you've said it might be, Trentepohlia...It's looking like your spot on.

I found an image on geograph that looks exactly like mine, it also added that "Trentepohlia are commonly found on trees and also on rocks, especially in the damper western regions of Britain". That seems to fit the habitat quite well as I live in Bristol and the area I found it in is very damp with impeded drainage. I agree with you Alan, it gets a bit frustrating trying to identify finds just from photographs. I think I'll need to invest in a microscope at some point, just so I can keep a more accurate record of what I've found. This fungi hunting lark can become a bit addictive, eh?

Appreciate all the extra info as well...just makes it more interesting.

Many thanks

John

RingwayRoy · #7 (**permalink**) 19-08-2009, 10:53 PM

New lichen spotter here..

I found something similar on a recent walk which also had me stumped.

AlanS · #8 (**permalink**) 20-08-2009, 01:17 AM

Quote:

Originally Posted by RingwayRoy

New lichen spotter here..

I found something similar on a recent walk which also had me stumped.

Yes, this is the same bright orange Trentepohlia that is evidently spreading in western Britain, forming extensive sheets on trees. I have collected material myself but have not got around to looking at it yet.

It is evidently causing confusion - a new Wikipedia page shows the same thing, as "Mustard Powder lichen"! The author even cites the Chysothrix candelaris page on my lichen site, though he/she evidently hasn't actually looked at my photograph or read my text (or, indeed checked how I spell my name). But I suppose that is Wikipedia ...

I have a webpage on Trentepohlia at Trentepohlia (University of the West of Scotland: Biodiversity Reference), which gives some background, but I feel sure that this one is different from the two species I feature. I do have to look into it. (Note that this page will have to move during the next month, as the old server will be retired, switched-off and sent to server-heaven. My pages there are being moved to Biodiversity Reference, but this site is not properly in operation yet. With luck I shall add better photographs of T. abietina and of this new orange one.)

Alan