Small white toadstools on fallen, mossy tree

Small white toadstools on fallen, mossy tree

Observation - Small white toadstools on fallen, mossy tree - UK and Ireland. Description: Small. About half an inch across. On mossy, fallen tree in mixed woodland. I don't know what kind of

Small. About half an inch across. On mossy, fallen tree in mixed woodland. I don't know what kind of tree. White gills.