Dioctria's picture

Crustose Lichen

Observed: 10th October 2008 By: DioctriaDioctria’s reputation in Fungi and LichensDioctria’s reputation in Fungi and LichensDioctria’s reputation in Fungi and Lichens
30D_00946 1

On acid rocks at Bradgate Park, Charnwood Forest, Leics. I'm not certain that the second photo is the same species but it has the same colour and form so I have included it. The closest I could find was Ochrolechia but I'm very unsure of that.


No identification made yet.

Species interactions

No interactions present.


AlanS's picture


Without being able to examine these with a lens and with chemical tests, these are very difficult to name (sez he pretending that he could name them WITH a lens and chemical tests).

I am tempted to add a 'revision' as "Nasty, white, indeterminate, crustose lichen on rock" - a very common taxon.

However, a few ideas kick around. I don't think the two are the same, different margins for a start.

Number two has the general appearance of "Unexciting grey-white lichen that I know is something very common but I can't quite put a finger on it". This sometimes morphs, after a few minutes of puzzlement, into sterile Ochrolechia parella, which it could be.

Number one looks a lot more interesting. It bears an intriguing resemblance to Lecanora swartzii, but rarity and geography suggest it cannot be that (but would be very interesting if the thallus was C+ orange and the rocks). Nevertheless, it could be one of that group. The most likely possibility may be Lecanora rupicola, a widespread and very variable species.

But I fear all this is speculation - I think I have to go with Nasty, White, Indeterminate, Crustose Lichen on Rock.


[note added in edit, 27.7.11: "C+ orange and the rocks" was intended to read, "C+ orange and the rocks are metalliferous".]

Dioctria's picture

Many thanks for that Alan,

Many thanks for that Alan, informative and entertaining! :-)


gardener's picture

:) I'd add 'Avert eyes and

:) I'd add 'Avert eyes and walk away quickly!'

Dioctria's picture

There's More!

Ah, that would explain why this one went unremarked! ;-) I might just be starting to get a feel for what can be done from a photo...

Unfortunately my last few from that day at Bradgate are also grey crustose lichens! I'll put them up as a job lot in case either of you could give them the once-over for anything identifiable, but I won't get my hopes up.


gardener's picture

Chemical spot tests

Hi David,

Some of these can be rendered a bit more more do-able if the results to at least K and C chemical spot tests are known:

Dilute caustic soda for K, Milton for C, small dropper bottles available via most chemists

AlanS's picture

Agreed, more or less.

Caustic soda is actually sodium hydroxide, which usually but not always gives the same results as potassium hydroxide (K).

Milton, as sold for sterilising babies (or is it their bottles?) is ok when absolutely fresh as a pure and trustworthy souce of 'C' (sodium or calcium hypochorite), but is less than the recommended strength and quickly loses its strength once the bottle is opened, even if the lid is replaced tightly and the bottle is rfefrigerated.

Nevertheless, an expert of my acquaintence doesn't even start thinking about most crustose species until she has done the tests, and she is right.