I found some Hymenoscyphus-like apothecia on cupules and acorns of Quercus robur, spores seem to fit with Hymenoscyphus fructigenus too.

Habitat: Found yesterday (late August) after some rain, on acorns and cupules of Quercus robur, in damp and shady areas under a dead hedge fence (stacked dead wood), generally quite a damp muddy area, in mixed deciduous woodland with lots of Quercus and Corylus, ~25m elevation, Lower Weald, England.

Apothecia: Several with 0.5-1.5 mm diameter and some larger ones observed, < 10 mm stipe length depending on evironment, initially whitish and more translucent, yellowing with age (especially noticeable on disc), singular to caespitose, superficial, cyathiform and eventually discoid, margin more whitish and often undulating when mature, appearing to display geotropic growth and growing out of holes in the acorns.

IKI: Rings bb, hymenoscyphus-type, VBs with strongly dextrinoid reaction.

Spores: Elongated lacrymoid in face view, base acute and apex hemispherical, constricted at the middle and scutuloid in profile view, many small to medium VBs and some tiny LBs, appearing aseptate and uninucleate.

Free spores measured in water: 17.3-20.6 (21) x 4.4-4.7 um, Q = (3.7) 4-4.6 (4.7), n = 14, mean 19.3 x 4.5 um, Q mean = 4.2.

Asci: Cylindrical-clavate, apex appears acute-truncate, 8-spored, poroid, simple septa (furcations not clearly observed).

Paraphyses: Narrow cylindrical, with many small VBs, especially towards apex, apparently several at least 2-septate, most branching close to the base.

Ectal ex: Looks like textura prismatica (typica?), some narrower external hyphae with VBs.

Medullary ex: Looks like textura intricata.