On a barkless poplar branch, we found hairy discs that appear to be attached to a black subiculum.
We suspected Mollisia, but in KOH, we saw no green reaction of the excipulum and a faint yellow KOH reaction of the paraphyses.

Disc:
The inside is very dark gray, the underside is brown in the center and a bit towards the edge, the last bit towards the edge has white hairs. The transition is clearly visible in photos 29-042 and 29-048.
The dark brown hyphae of the subiculum are also visible in photo 29-042.
Does the brown structure appear to be broken or old?
There are strange, large spores lying between the hairs of this disc.

Structure:
Textura globosa angularis -> prismatica.

Asci:
Measured in water: 38.3 - 58.67 (58.7) × (5.7) 5.71 - 6.7 µm, Q = 5.7 - 10.1 Croziers + and Lugol +

Paraphyses:
Cylindrical, branched at the base, with a sept, filled with a large guttule.

Spores:
Hyaline, with two larger and smaller guttules.
Measured in water: (7) 7.1 - 9.1 (10.1) × (2.7) 2.72 - 3.25 (3.3) µm, Q = (2.2) 2.4 - 3.3 (3.5)

In Melzers and KOH + Congo Red, we see no amiloÏd or dextrinoÏd reaction in the hairs or excipulum. We see no solid tips in the hairs.

Thanks in advance for your help, Geert&Margot