A brittlegill. An edible species fairly common in beechwoods and mixed woods. Just make sure any species you collect don't have a volval sac at the base of the stem which would put them in the deadly Amanita group. Should have a mild taste - some are peppery or bitter , but not poisonous. One of a great range in a great variety of colours, but the white gills and stem, and the yellow cap tending to ochre give it away. I thank Andrew Wright and Jonathan Revett for their help in identifying this mushroom.