Many thanks, Otto,

Dactylospora is a great suggestion.  Certainly, I assume the amyloid halo is the amyloid gelatinized layer on the clavate asci.  In the absence of available literature, i do not think that i can get any further.  I am pretty sure that it is not lichenicolous.  The apothecia are tucked into splitting lenticels, in what would be very low light and there is no evidence of any algal cells, either in these 'pits', or, indeed, on the surrounding bark. From what I gather there are saprobic species in the genus, but I cannot find anyhing that would take me to a species.  Unfortunately, the Dactylospoaceae appear to be somewhat out on taxoomic limb.  Again, thanks for your help. I remain open to any suggestions of where i can explore this further. I have spent a long time trying to find a name and it would be nice to get it to species.

Simon

There exists a non-lichenicolous species with warted spores which occurrs on Prunus spinosa and Crataegus, with an excipulum that turnes bright purple-red in KOH. You can view images in my folder "Dactylospora muriform" in 6b Lecanoromycetes - Lecanorales. We have no name for it.

The name Dactylospora was recently replaced by Sclerococcum.

Again, thanks, Zotto,

My apologies, but I do not know how to locate the document to which you refer, on 'Dacytylospora muriform".    It would be good to see images of your muriform spores. 

I am finding it hard to believe that there is not a name for this fungus, out there somewhere.  It has a combination of quite distinctive characteristics.  At least it looks a bit odd, from my position of relative ignorance.   On what basis has Dactylospora been tranferred to Sclerococcum?

Best wishes,

Simon

Sclerococcum is an anamorph and it was during 1 fungus 1 name that the transfer was necessary.

go here: https://www.in-vivo-veritas.de

there to Ascomycetes illustrations.

Many characteristic species are undescribed or so badly that it is impossible to recognize them.