Hello.
Some small pycnidia sprouting abundantly on an acorn on the ground.
Blackish in color like grains, very superficial, poorly adhered to the substrate, with a size between 154.54 to 219.7 µm. wide and with a height of between 70.74 and 123 µm.
Hyphae from the wall of the perithecium are heavily pigmented brown and have a labyrinth-like arrangement.
Cylindrical conidiogenous hyphae with measurements of (10.7) 11 - 22.1 (24.8) × (1.6) 1.7 - 2.6 (3.6) µm.
Cylindrical conidia, many of them tapering, with guttulas inside and measurements of:
(6.7) 7.5 - 9.2 (10) × (2.1) 2.2 - 2.9 (3.4) µm
Q = (2.2) 2.6 - 4.3 (4.6) ; N = 40
Me = 8.2 × 2.5 µm; Qe = 3.3

I understand the difficulty of identifying species like this, but given the specificity of the host, perhaps there is someone here who knows it. It's just that I have the feeling that I've seen it before somewhere, but my memory is no longer enough.
Thank you very much in advance.
Kind regards.