Sheathed Woodtuft - Kuehneromyces mutabilis

A smallish brown mushroom found in clusters and troops on deciduous stumps and logs.  The cap is broadly convex with an umbo, tan brown with a paler centre, giving a zoned appearance . The gills are pale ochre, darkening as the spores mature.  The stipe is fibrillose and whitish above the ring; covered in small brown scales below the ring.  The section of stip above the ring of older specimens may become darker. Spores oval, brown and smooth. 

The extremely toxic Funeral Bell (Galerina marginata) is very similar but has a silvery fibrillose stipe below the ring, and larger spores with small warts. The two species can be very difficult to tell apart.

Photograph the whole clump, plus a mushroom from top down, in side view and underneath; your photos must show the stipe clearly.  Also note habitat and substrate. 

On stumps, felled trunks and logs of broadleaved trees

Throughout the year, but most plentiful in summer and autumn.

Widespread and common (Kibby, Vol.3, 2021)

Fairly frequent in Leicestershire and Rutland.

https://www.first-nature.com/fungi/kuehneromyces-mutabilis.php