Hello,
there is an interesting collection of a tiny Pyrenomycete:

black perithecia near thallus of Lemmopsis lutophila, perithecia egg-shaped with one rounded and one somewhat tapering end, c. 200 µm long and 150 µm wide, upper part of perithecia with dark prorate cells
paraphyses lacking, hymenium J-
asci J-, with 2-4(5) spores, spores 2-celled with mostly one large oil droplet per cell
spore size in 2-spored asci: 14-15 x 5-5.5 µm
spore size in 3-spored asci: 10-14 x 5-5.5 µm
spore size in 4-spored asci: 6-13 x 5 µm

I first thought of an lichenicolous fungi but there is nothing even remotely resembling this collection. Maybe someone has another idea.

Best regards and a happy Easter
 
Jan