Hi Josep
Thanks to you, I narrowed down the circle of suspects. At first I hesitated between Nemania and Hypoxylon.
Nemania serpens was initially rejected from the circle of suspects, although the macro was very similar. The dimensions of the apical apparatus in this genre are too large.
In my:
Me = 2.7 × 1.8 µm; Qe = 1.5

2.60 1.92
2.67 1.78
2.68 1.99
2.59 1.65
2.85 1.78

I considered Nemania atropurpurea. However, I have comments on the color of the spores. I would rather consider them light brown, whereas N. atropurpurea should be dark brown ??

I looked at all the possibilities and came to the conclusion that N. serpens is probably the most suitable for my collection.
However, taking into account the fact that the dimensions of my collection, despite being within the limits of this species, are however close to their limit values, therefore I should consider mine as:
Nemenia serpens sensu lato !?

I also measured the spores in KOH and they come out a bit bigger ??

I also measured the thickness of the spore wall. It turns out that they have> 0.5um which according to Czech Mykol can be a decisive feature in distinguishing these species. Nemania atropurpurea should have thinner.

Thank you and best regards
Mirek

Hello Mirek and Josep,

Hi Jacques
Thank you very much for valuable suggestions.
This is my first Nemania collection which I microscoped so please forgive me for not providing all the features needed for identification. Beginnings are difficult and especially in such a difficult kind.
A comparison with N. serpens and N. atropurpurea at present is not possible. I don't have fruiting bodies for these species, but in time I'll try to make up for these shortcomings.
I downloaded the monograph on Granmo et al. (1999). if someone was also interested, it is available at:
https://www.researchgate.net/publication/259034689_The_genus_Nemania_sl_Xylariaceae_in_Norden

Regards
Mirek