Mushrooms are a type of fungi. They do not contain chlorophyll and hence cannot manufacture their own food. Most mushrooms are edible but there a few varieties that are also poisonous. Toadstools are traditionally poisonous or inedible mushrooms containing a poison which is lethal. However, scientifically, there is no difference between mushrooms and toadstools. Some misconceptions related to poisonous mushrooms are that a poisonous mushroom is umbrella-shaped or it blackens a silver fork. Many species of mushrooms seemingly appear overnight, growing or expanding rapidly.