Peltigera membranacea

[chrisjohnson]

I am reasonably sure about the identification of the following specimens as Peltigera membranacea. I have based this on the presence of bottle-brush type rhizines, white underside with a prominent network of white veins. Image 1 shows a typical tomentose grey thallus, whilst the others are green-olive with the hairs on the upper surface limited to the outer edge (only visible under a lens). However when dried the colour turns to grey and the hairs are more noticeable
Assuming my id to be correct, is this variation due to hydration, age or just natural variation? Images 1 & 2 were photographed in August and 3 & 4 in February. All were on South Uist, apart from 2 which was on North Uist. The habitats were similar - wet, grassy, moorland edge.

Chris

[AlanS]

Yes, I agree. The rhizines look very typical.

I think the variation in colour is OK, but one trap, especially with water-soaked material, is that P. praetextata can look surprisingly similar, and it can take a while to find the isidia that are diagnostic for that species.

Alan

[chrisjohnson]

Thank you Alan.
As a novice I tend to look at most things carefully and I've not seen any isidia on the specimens I've examined. However I have noted the tip. These small "what to look" for tips are very useful.

Christine