High Quality Content by WIKIPEDIA articles! Psilocybe semilanceata, commonly known as the liberty cap, is a psychedelic (or "magic") mushroom that contains the psychoactive compounds psilocybin and baeocystin. Of the world`s psychoactive mushrooms, it is the most common in nature, and one of the most potent. The mushrooms have a distinctive conical to bell-shaped cap, up to 2.5 cm (1.0 in) in diameter, with a small nipple-like protrusion on the top. They are yellow to brown in color, covered with radial grooves when moist, and fade to a lighter color as they mature. Their stems tend to be slender and long, and the same color or slightly lighter than the cap. The gill attachment to the stem is adnexed (narrowly attached), and they are initially cream-colored before tinting purple as the spores mature. The spores are dark purplish-brown in mass, ellipsoid in shape, and measure 10.5–15 by 6.5–8.5 micrometers.