Hi Ake, 

Did you test IKI (Lugol) on asci apex ? This would give an essential character to a Hymenoscyphus possibility and would reject - or not - an Ombrophila species , which I suspect. 
 Amitié
Michel

The spore areclearly scutuloid, so I am sure it is not an Ombrophila. Anyway, IKI reaction and croziers are essential. H. ombrohiliformis occurs on branches or pericarps of Fagus and has croziers. The similar H. syringaecolor, which has spore guttules very similar to this one here on Carex, occurs on Fagus leaves and lacks croziers.

Thanks for your comments!
I searched for croziers, and couldn't find any (but they are not always easy to see). Unfortunately I have no IKI, so I couldn´t check the reaction. Anyway - the substrate (Carex) is a bit confusing. There was a discussion about H. ombrophiloformis vs. syingaecolor in Ascomycetes of the world a year ago. Björn Wergen wrote that he was convinced that "there are additional undescribed species, growing on different substrates, all under the name 'H. syringaecolor'." Maybe that´s the problem? Now I will look for croziers a second time, and I´ll see if I can check the IKl reaction as well.

Regards
Ã…ke

I d not know on which data Björn relies. H. syringaecolor is very rarely reported in the literature. Did he say which substrates he means to have similar species?

He just mentioned this:
"According to the key from Declercq, H. ombrophilaeformis has somewhat broader spores and grows on 'twigs and branches of Acer and Fagus in wet habitats'. I also have a collection of a Hymenoscyphus species growing on soil and buried wood."

In another discussion (with pictures) about the species, back in 2023, he wrote: "Hymenoscyphus cf. ombrophiliformis (also H. "ombrophilaeformis"), on plant debris on wet muddy soil, Schwarzwassertal (Austria), 28.08.22.fb 2-5 mm, with distinct stalk, purplish all over and somehow looking like a species of Ombrophila.                                                          spores (20.2) 20.5 - 23.9 (26.4) × (4.6) 4.7 - 5.2 (5.3) µm; Q = (3.9) 4 - 5 (5.4) ; N = 8. Me = 22.2 × 4.9 µm ; Qe = 4.5.                                                                           
Asci without croziers, IKI+bb.                                                                                               
Any better ideas? Its a true Hymenoscyphus as far as I can see and there are only H. ombrophiliformis and H. syringaecolor described with such purplish colour, the latter one way smaller than the collection shown here."

Regards
Ã…ke

Can you provide a link to this species and discussion?

The links:

https://www.facebook.com/groups/ascomycetes/posts/3889408634644645/

https://www.facebook.com/groups/ascomycetes/posts/3340592739526240/