Variable in colour; caps greyish-brown but can be blackish in var. leucogala (nigra) or white in var. candida.   Gills whitish. The stipe is pale brown, may be pruinose.  Fresh specimens exude a whitish juice when stem is broken near the base.  The smell is slightly radish-like. 

other Mycena

white 'milk'

This is a difficult speces to identify with certainty unless the white 'milk' is observed.  If this is not recorded, it should be microscopically examined from a specimen.  Expert verification prior to submssion to NatureSpot may be neeed.  Also photograph from top down, in side view and from underneath to show gills and full length of stipe.  Note habitat and substrate.

It is found in mixed woodland

Autumn

Widespread and common in Britain.

Common in Leicestershire and Rutland.

https://www.first-nature.com/fungi/mycena-galopus.php