perhaps compare M. revincta.
Yours, Lothar

M. revincta ist wohl bezüglich der KOH-Reaktion recht variabel, ist vermutlich auch noch eine Sammelart.
Hier kannst Du wertvolle Infos lesen:
https://asco-sonneberg.de/pages/gallery/mollisia-revincta-epilobium-koh-110910-01xs21751.php
Dort steht u.a. auch:

Auf die KOH-Reaktion kann man sich wahrscheinlich nicht gut verlassen. Zwar ist sie meist mittelstark und vergänglich, jedoch sind mir von Rubus auch stark gelbe und anhaltende Reaktionen bekannt

Dein Fund ist ja von Rubus.

Ich weiß nicht, warum die Art in Pyrenopeziza geführt wird. Und ja: die Vakuolenkörper in den Paraphysen stehen für Mollisia.

ah - sorry that I wrote in German. I thought you would be German, too, but now I see you are Danish :-)
Yours, Lothar

I see that Zotto has a folder called "clavata (=alcalireagens) Rubus + Reynutria KOH+, ap. smooth, 7.5-11,5 " which to me looks similar too. Could M. clavata, M. revincta on rubus, M. alcalireagens all be the same thing?

Hello,

Mollisia revincta is a complex of species with small spores on herbaceous stems. According to my own collections there are quite many genetically different species which I used to "determine" as revincta. There are collections with strong and with weak yellow reaction and even without. I did not study that complex ion detail, but I'm convined that Mollisia clavata is a different species characterized by the marginal cells. What concerns Mollisia alcalireagens, there is the problem that the i examined the holotype collection PRM899458 and found it to be completely KOH-negative (also NH3-negative). I don't know how to interprete this. On the other hand I have collections from Rubus which are strng yellow whereas collections from Filipendula (which I think to be the "true" revincta" are usually only weakly positive.

No great information all in all, I know. That group needs revision ....

all the best,
Andreas