A small (up to 3 mm across), bright lemon yellow saucer-shaped disc on decaying wood. It dries to a more orange colour.  The surface is smooth and the disc has a short tapered stem.

Sulphur disco Calycina chloroflava is slightly smaller and associated with a pyrenomycetous fungi.  Bisporella are a paler yellow, and smaller

Photograph in habitat; note substrate and any associated plants or fungi

On the dead and decaying wood of deciduous trees, often in woodland.

Throughout the year

Fairly common and widespread in Britain.

Fairly common in Leicestershire and Rutland.