A very variable grassland Mycena, with a brownish cap that may have pinkish, olive or yellowish tinges.  The gills are grey and usually have an edge coloured the same as the cap; sometimes only the gill edge closest to the margins si coloured.   It has a nitrous or radish-like smell. 

Several other grassland Mycena are similar; however the brownish gill edge should help identification

Photograph from top down, in side-view and from underneath to show gills; note smell, habitat and substrate.

Lawns and other grasslands

Autumn.

Widespread and fairly frequent in Britain.

Fairly frequent in Leicestershire and Rutland.