Mushrooms are usually the most obvious fungi found in forests and meadows. Some, like morels and chanterelles, are prized for their gourmet qualities and are sought by foodies and chefs. Others, though, can cause problems if eaten. "Lots of mushroom have the potential to make you sick," Stephenson says. "Relatively few will kill you, but there are some that are deadly enough to knock your socks off permanently." The Amanita bisporigera, or "destroying angel," may look modest and nondescript with its silvery-white sheen, but it's one of the most poisonous mushrooms found in the United States.