Hello,
yesterday I collected this Phaeohelotium on a decaying trunk of Fagus sylvatica (in the field I though it would be Bisporella/Calycina). The apothecia measured up to 7 mm, but mostly up to 4 mm, were vivid yellow, not reddening.
Ascospores (13.9)15.4-18.2(19.7) × (4.1)4.2 4.7(4.8) µm, Q = (3.1)3.5-4.2(4.6), n = 40, 
Me = 16.9 × 4.4 µm, Qe = 3.8. Most of them were non-septate, some 1-septate, a few 2-septate and a single 3-septate ascospore was observed. 
Asci bb (Hymenoscyphus-type), with croziers. 124-135 x 8-11 µm.
Ectal excipulum textura globulosa-angularis, medulla t. intricata.
Using Bernard´s key I came to Phaeohelotium monticola, but still feel a bit uncertain due to the possible confusion with P. epiphyllum. Based on the information in this forum and after comparing photos on reliable webpages, it seems P. epiphyllum should have less vivid colour, smaller guttules inside paraphyses and should become red when damaged. Nevertheless, I would like to consult this find. 
Zuzana