The hemispherical cap can reach 6 cm diameter. It is smooth and sulphur yellow with an orange-brown centre and whitish margin. The crowded gills are initially yellow but darken to a distinctive green colour as the blackish spores develop on the yellow flesh. It has a purple brown spore print. The stipe is up to 10 cm tall and 1 cm wide, light yellow, orange-brown below, often with an indistinct ring zone coloured dark by the spores.
Found growing on the dead wood of both deciduous and coniferous trees; from spring to autumn.