Hello!
On a fallen twig (possibly Corylus) I found what I assume is Nectria sp (let's say Nectria sp1, because I have another one, more on that later) Location Slovenia-Bovec 480 m altitude, mixed forest, January 2025.
The first photo is a fresh specimen, the second and third are cross-sections of the air dry fungus. I used KOH and Meltzer. I have no knowledge of growing in culture. Maybe someone will recognize the fungus based on this information. Although A monograph of Allantonectria, Nectria, and Pleonectria (Nectriaceae, Hypocreales, Ascomycota) and their pycnidial, sporodochial, and synnematous anamorphs is an excellent work, unfortunately I was not successful?
The spores are 15.4 x 5.8 microns
Please help!