A bright sulphur-yellow Tricholoma with a convex cap, sometimes with a slight umbo.  It has a very unplesant smell of coal-gas.  The stem and gills are also sulphur-yellow.  A variety (var. bufonium) with a pinkish brown cap also exists.

Other yellowish-brown Tricholoma occur in the UK, but mainly as northern or Scottish species.  T hemisulphureum also has a yellowish cap and coal-gas smell, but is associated with Rock-rose; to our knowledge it has not been recorded in VC55.

smell

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

In deciduous and mixed woods, usually with Oak or Beech.

Late Summer to Autumn.

Widespread but local in distribution.

Occasional in Leicestershire and Rutland.

https://www.first-nature.com/fungi/tricholoma-sulphureum.php