Hi Zaca,
the substrate looks like bark, not herbaceous and the ascospores are not intact, most of them are burst with the germ slit wide open. I agree it is xylariaceous, likely Hypoxylon fuscum.
Cheers,

Jacques

Merci Jacques,
For your opinion . It has the overall appearance of Hypoxylon , but I do not know how to separate it from the other Xylareaceae . You must be right Also about the host, but the observation was made at a place with tropical vegetation (tropical garden inside the city) and I don't know how to classify the plant ; It was not a tree or shrub but it has some bulbous base where the fungus developed.
Thanks again for your help,
Grateful,
zaca

Dear all,This time I could see the spores well and at all stages of development. The dimensions are a bit different than previously:
(14) 14.8 - 16.5 (17.7) × (6.7) 6.8 - 7.9 (8) µm
Q = (1.9) 2 - 2.28 (2.3) ; N = 31
Me = 15.5 × 7.3 µm ; Qe = 2.1
I add a set of photos.

Best wishes,
zaca

Hi Zaca,
now that you have seen asci which are unitunicate, cylindrical, with an amyloid apical apparatus and brown one-celled ascospores you are indeed dealing with a Xylariaceae. The stroma surface is coloured, inside is homogeneous, a small chip of external stroma should yield pigments in a drop of 10% KOH. If the pigment is greenish yellow to dark olivaceous, depending on how big is the chip of stroma and if ascospores have a sigmoid germ slit and a perispore dehiscing in 10% KOH, you can consider H. fuscum.
The fact you found it in a tropical environment expands considerably the range of possible species, especially if there are tropical shrubs and plants imported from tropics.
Now check the pigments, the perispore and the germ slit and get back to the forum.
Cheers,

Jacques