Salut,
Après avoir lu la clé de Bernard Declercq à Hymenoscyphus (2004) je pense que cela est un ensemble difficile des Ascos. Nous avons trouvé ce spécimen à proximité de la Hymenoscyphus repandus que j'ai posté récemment (sur une fleur-tête mort de Cirsium arvense). Je pensais que ce serait la même chose - elle est aussi de couleur jaune jolie - mais il est tout à fait différente au microscope.

Hi,
Having read through Bernard Declercq's key to Hymenoscyphus (2004) I'm aware that this is a challenging set of microfungi. We found this specimen close to the Hymenoscyphus repandus on a dead Cirsium arvense flower-head which I posted recently. I assumed it would be the same, as it is a similar nice shade of yellow – but it is quite different microscopically.
Habitat –single specimen on rotting herbaceous debris in a bog on Carboniferous Millstone Grit, Peak District, N. England, altitude just over 300m.
Size: "cap" 2mm, "stalk" 2mm x 0,5mm. Stem base possibly from sclerotium (from photo) – but unfortunately the small piece of stem has gone missing.
Surface smooth with no hairs on x 45 stereomicroscopy.
Texture gelatinous, very difficult to section or to squash. I had to eventually make a few crude squash preparations, so no specimen remains for the herbarium. Much of the fungus consisted of what seemed to be thin- walled gelatinised hyphae, with amorphous material staining in Congo Red. One hypha was much thicker and looked like a Hyphomycete.
The spores were quite different to Hymenoscyphus repandus – oval, with rounded ends, 10-12 x 4-4.5, hyaline with small inclusions (difficult to see).
Asci were typically 120 x 6, no croziers, blueing only faintly in Lugol. 8 spored, uniseriate.
Paraphyses thread-like, 2 um wide.
As the fungus wasn't soft in texture I suspect it may not by Hymenoscyphus at all – but am at a loss to assign it anywhere else except Sclerotinia.
Cordialement,
Steve