Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
My suggestion of Porpidia tuberculosa is only tentative!
Details of whether the rock/substrata that the lichen is on is acidic or basic (limestone, mortar etc) are vital when trying to identify crustose species, as are results to the basic chemical tests.
Dirina massiliensis: On limestone, C+ rose-red, K-
Porpidia tuberculosa: On acidic rocks, C-, K-
I'll go back at some point, armed with that information, some chemicals and a dogged determination!
Hi Nigel - this link might be of help on the chemical front:
Unfortunately (nuisance though it is!) there is only only so far that its possible to go with lichen identifications before its necessary to resort to at least the K and C results.
So many of the crustose species are horribly similar that sometimes that's the only way of arriving at or confirming an identification. Of course some then need P results or spore examination or even thin layer chromatology, but K and C are good starters!
Thanks again, Jenny. I've read that page before, but I've been trying to ignore it due to the inconvenience of carrying dropper bottles around, but no - it's going to have to be.
2012 will be the year that I start bleaching lichens, and attract even more funny looks from walkers!
I am happy this is Dirina. One of the photographs shows it slightly damaged, and where it is wounded it is orange. Trentepohlia photobiont showing through!
(Of course, this doesn't separate it from Schismatomma decolorans if the latter decides to grow on a shady rock - I have seen the two together and looking near identical except the Dirina has more delimited colonies. Bleach sorted them out.)
Lat/Lng: 53.64107, -2.219574
OS grid ref: SD855160