Psilocybe semilanceata or liberty cap is a psychedelic mushroom that contains the psychoactive compound psilocybin. They grows in grassy meadows, grassy heath and in the most unexpected sites; they have a distinctive conical cap with a small nipple on the top, often described as a pixies hat. They are yellow to brown in colour, almost transparent when young and wet, then they fade to a lighter buff color as they mature. Their stems tend to be long and the same colour or slightly lighter than the cap. The psychoactive content and relative safety, when taken in small to moderate doses, makes them a popular hallucinogenic, still illegal though.