A small white or cream coloured mushromm, wth a darker central spot and a pleated apprearance and scalloped edge.  The gills are whitish cream, attached to a collar surrounding the stem.  The stipe is stiff, slender and dark brown below, paler above.

Other small Maramius, including some with a collar, and Marasmiellus ramealis, the Twig Parachute, which has a pale, tapered woolly stipe 

Photograph from top down, in side-view and underneath to show gills and collar; ensure your photo clearly shows the length of the stipe from gills to base.  You must note substrate and habitat.

Deciduous woods, growing on dead twigs and leaves.

Found from summer until winter

Common throughout Britain

Common in Leicestershire and Rutland.

https://www.first-nature.com/fungi/marasmius-rotula.php