Confidence: It's likely to be this, but I can't be certain.
Notes: I cannot be certain, as the diagnostic marginal isidia are not visible here, but they are very often hard to find when the material is producing apothecia (fruitbodies), as it is doing here. It is clearly one of the species with a tormentose upper surface, and as habitat and rhizine characters rule out P. canina or P. rufescens, this leaves P. membranacea as the only other contender. This has a more uniform tomentum, a more regularly wrinkled upper surface and a generally neater appearance. So, by elimination, this is P. praetextata. It looks reasonably typical. Alan.