Phylum: Basidiomycota Family: Mycenaceae
Mycena hiemalis (Osbeck) Quél.
A widespread species but not particularly common. Found on moss-covered trunks of broadleaved trees, often in association with other Mycena species
References:
Aronsen & Laessoe (2016) The Genus Mycena
Robich (2007) Mycena d'Europe