Hello.
A tiny ascomycete, appearing as erupting grains, barely embedded in the substrate, blackish in color, sprouting sparsely but massively from decomposing soil stems of Rubus sp.
It measures only 0.4 to 0.7 mm in length, 0.3 to 0.4 mm in width, and 0.2 mm in thickness. The asci are octoporous, lacking hooklets, and exhibit a very slight amyloid reaction in a tiny apical apparatus with Melzer's reagent. This apparatus, resembling two dots, is more visible when using KOH. Interascal material appears as filiform, narrow paraphyses or pseudoparaphyses with vacuolar content.
Spores between ellipsoid and fusiform, with one more pointed end and a septum near this end, this septum being more visible using Melzer's reagent. Measurements in water of the mature spores measured within the ascus are:
(20.8) 22 - 24.5 (25) × (9.4) 9.5 - 10.6 (10.9) µm
Q = (2) 2.1 - 2.56 (2.6) ; N = 20
Me = 23.2 × 10.1 µm ; Qe = 2.3

Based on the microscopic image obtained, I think it could be the sexual or perfect form of an Apiospora, which has left me stuck on this genus and I can't think of any other possibilities.
Consulting Index Fungorum, I came across a couple of Apiospora species, likely associated with Rubus: Apiospora rubi-fruticosi and Apiospora rubi-ulmifolii. However, I haven't been able to find any information about either of them.
I'm not sure if I'm on the right track. Any input would be greatly appreciated.
Thank you in advance.
Best regards.