Panaeolus foenisecii
Panaeolus foenisecii, commonly called the mower's mushroom, haymaker or brown hay mushroom, is a very common and widely distributed little brown mushroom often found on lawns and is not an edible mushroom. In 1963 Tyler and Smith found that this mushroom contains serotonin, 5-HTP and 5-hydroxyindoleacetic acid. In many field guides it is erroneously listed as psychoactive; however, the mushroom does not produce any hallucinogenic effects. Habitat. The species may be the most common to appear in lawns in the Pacific Northwest. Gallery. The following two images are of "Panaeolus foenisecii" in the wild with  two magnifications of the spore print. Similar species. Similar species include "Agaricus campestris", "Conocybe apala", "Marasmius oreades", "Psathyrella candolleana", and "Psathyrella gracilis". It is sometimes mistaken for the psychedelic "Panaeolus cinctulus" or "Panaeolus olivaceus", both of which share the same habitat and can be differentiated by their jet black spores. This is probably why "Panaeolus foenisecii" is occasionally listed as a psychoactive species in older literature.