Kidney shaped or shell shaped, surface smooth to finely downy, lobed, margin often notched, whitish to pale brown, to about 20mm across, but often less. Gills fairly distant, whitish then pinkish brown. 

other Crepidotus 

microscope

Identification is very difficult, requiring microscopic examination.  If you have not done this or if the specimen has not been examined by an expert, please submit your record as genus only (Crepidotus).

On twigs and branches, usually from deciduous trees.

Autumn to winter.

Widespread and fairly frequent in Britain.

Fairly frequent in Leicestershire and Rutland.

https://www.first-nature.com/fungi/crepidotus-cesatii.php

Formerly placed in the Inocybaceae.