Psilocybin mushrooms are not specifically named in the U.S. federal scheduling system, however their two primary active chemicals Psilocybin and Psilocin are both Schedule I in the United States. This means they are illegal to manufacture, buy, possess, or distribute (sell, trade or give) without a DEA license.
Fresh and dried psilocybin mushrooms are considered containers of Psilocybin and Psilocin, making them illegal to possess as well.
Because spores contain no psilocybin or psilocin, they are legal to sell and possess (
in all states except California, Georgia, and Idaho). But in most states, it is illegal to cultivate or propogate spores into mycelium since mycelium generally contains both psilocybin and psilocin.
Psilocybin mushrooms are illegal in every state in the United States except Florida (see below).
Psilocybin Mushroom spores are legal to possess in every state except California, Georgia, and Idaho.
Florida
Florida stands out because of a decision in 1978 in
Fiske v Florida by the Florida Supreme Court which ruled that wild-picked psilocybin mushrooms could not be legally considered "containers" of psilocybin and thus would have to be specifically listed in Florida law by the legislature if they meant to make them illegal. Since the Florida legislature has not chosen to change the laws since then, wild Psilocybin mushrooms are presumptively legal to possess in Florida. This does not mean police won't arrest people for possession of even wild mushrooms, but this has been used as a successful defense against such charges.
New Mexico
New Mexico appels court ruled on June 16, 2005, that growing psilocybin mushrooms for personal consumption could not be considered "manufacturing a controlled substance" under state law.