Perhaps Heterosphaeria on a dicot stem? is the substrate woody? But that does not grow so gregarious and hasn't gel outside.

Hi Zotto
Yes, it's definitely wood!
(Salix, Prunus, and others)
I'll take pictures of the substrate later. I wait for the fruiting bodies to ripen but I ask because I would like to know what to pay special attention to?
I don't think I've ever had such microscopes?
Mirek

Do the conidia occur inside the asci?

Zotto,
So far, I haven't seen it?
I didn't want to spoil the material. Everything is very small. Sporocarps up to 0.5mm. I couldn't get a thin section today. I'll try later!

Hi Adam
Yes, of course P. padus very likely!
Thank you! It will probably be this species.
I will let you know how they mature !!
Once again, thank you everyone again!
Mirek

Hi Adam, indeed this possibility I also had in mind, but I could not remember that the apos are cleistohymenial there.

Hello all, 

yes, indeed, immature teleomorph + anamorph. I found the anamorph already on 25th December, seems to prefer the wet and colder part of the year. It's great, another locality.

Mirek, would you please send me the collection data? Was it a thin branchlet? Still attached to a living tree or recently cut? There are some spores visible inside one ascus, maybe those "conidia" are immature spores from damaged ascus? They look rather similar.

Viktorie

Hi Victorie.
As I mentioned earlier, this part of the forest was almost completely cut down. I found the sporocarps on a small fragment of a twig lying along with others on the ground. I suspect that the fruiting bodies of the fungus developed on growing branches. The felling was carried out not long ago.

I didn't have time yesterday, so I only took a few pictures. The reason for this was poorly ripe fruit bodies so there was no point in cutting them. Of course, I still grow them and I will try to check everything thoroughly. What I have marked as conidiospores are them. Proper spores are bigger but the pictures have not kept scale so it can be misleading.

The location is shown on the map:
https://www.google.com/maps/d/u/0/viewer?mid=1CccqU7DQhbqU9ynURZjauxQ7GVEWdWS0&hl=pl&ll=53.18188550000004%2C23.28406289999998&z=17

The macroscopic features are very similar to Godronia ribis, which I encountered several times on Ribis. I thought so at first, but the microscopic features are completely different.
Here are my Godronia ribis:
http://www.grzyby-pk.pl/gat_g/gat_godronia_ribis.php

Regards
Mirek