Hello Everyone,

I have been sent fruit bodies of a black pyrenomycete which does not seem to conform to the genus description of any of the main genera.

I have attached photographs of a fruit body, which was 13mm wide, when found and has shrunk to 9.5mm on drying. Tiny papillate ostioles pepper the surface, with the perithecia embedded below the dark brown crust.

The attached image of the section shows white flesh below the perithecia and the brown crust below this at the sides.

The host is believed to be a partially decorticated branch of Betula pubescens. Salix cinerea was also present and the location was very wet, near a stream. 

There are no KOH extractable pigments, either immediately or after 30 minutes.

The spores are initially hyaline, with 1 or 2 enduring guttules, becoming very dark brown by which time the guttules can no longer be seen. A faint germ slit at least two thirds of the spore length can be seen on some spores and all have a basal germ pore.

The microscopy sketch also attached.

I wonder if anyone has encountered this before and may know what it is?

Thank you,
With Best Wishes,
Peter.