I'm completely stumped by this little ascomycete.
I'm sure you can help me out.

The oak twig comes from the crown of an older oak tree;
it has been completely stripped of its bark and was snapped off by the wind.
After two days of rehydration, these cushion-shaped apothecia, growing in clusters and measuring approx. 0.3–0.8 (max. 1) mm, appeared amongst the 'green algae'.
A striking feature is the light-coloured fruiting layer with a dark margin, caused by 'marginal hairs' or the excipulum.
The outer surface of the cup is completely dark, featuring elements of a "Textura oblita"???.

Asci crousier +, IKL -. approx 90–115 (120) × 12–14 (16) µm.
Paraphyses approx. 1.8–3 µm wide, serpentine, with vacuoles that partially react to IKL.

Notable are the multigutulate spores, approx. 33–42 × 4.5–5.5 µm in size, some of which are septate.

Thank you very much for your help.

Kind regards,
Dirk