Bonsoir tous
I recently collected a discomycete with abundant pale apothecia on dead stems of Phragmites, cut and moved away from the water. It had an abundant dark chocolate subiculum, and based on the shortish spore size in the past, and using Ellis and Ellis, I would have tentatively called this Mollisia (Tapesia) evilescens. However I note from Andreas Gminder's key that the type of that taxon has cells which are brownish all the way to the margin; in my fungus all except the basal attachment and cells immediately surrounding it were not pigmented. I also note from Andreas' key that this is one of the difficult areas of Mollisia studies.

A particular feature of this fungus was the presence of globose bodies comprising numerous tiny acicular crystals. I wondered at first whether these were from an external source, but found them in all the several apothecia I studied. In addition I also could see refractive bodies within cells of the medulla base (see 7th image below). NB In the accompanying images the colours in the crystal bodies are due to polarised light, used to accentuate them, they were in themselves colourless.

Apothecia were white to pale grey, and up to 1mm diameter. No KOH reaction noted at either the macro- or micro- level.
Asci 8-spored, apex IKI deep blue, with croziers.
Ascospores 9-10.9 x 2.5-2.7µm.
Paraphyses, typical Mollisia-type with vacuolar contents.

Mollisia hydrophila is perhaps the closest species, but I note that that fungus has abundant crystals (not the case here); also as I understand it those crystals are of the familiar octohedral type (again not the case here). In addition that species should show a KOH+ reaction. Plus, that species has basal pads of dark hyphae, whereas this fungus had an extensive subiculum, encircling the Phragmites stems. While I appreciate that presence of a subiculum is not significant at the generic level, surely it has some taxonomic significance at the specific level?

Any suggestions to help ease my confusion would be welcome.

Cordialement
Chris