Psathyrella ammophila

Psathyrella ammophila is a species of fungus in the family Psathyrellaceae and is found throughout Europe. Commonly known as the dune brittlestem, this agaric primarily grows on sand dunes near marram grass, feeding saprotrophically on the decaying roots. In the Northern hemisphere, the season of growth is generally May to November. P. ammophila is variable in appearance, changing colour and shape during its lifespan. Initially bell-shaped and tan or pale brown, the cap gradually flattens and darkens, becoming dark brown with a depressed shape as it ages....read more on Wikipedia.