Panaeolus acuminatus

Panaeolus acuminatus, also known as Panaeolus rickenii is a common little brown mushroom.

This species contains small amounts of serotonin, 5-HTP, and tryptophan.

Description
This is a little brown mushroom that grows on dung and has black spores. It has a cap that is less than 4 cm across, hygrophanous, conic to campanulate to plane, usually with an umbo. The gills are dark purplish black, crowded, with several tiers of intermediate gills.

Habitat and distribution
Panaeolus acuminatus is a mushroom that grows in grass and in dung. It has been found throughout North America and Europe and is very widely distributed.