Scientists now use ‘mushroom’ in the strict sense to denote only the fruiting body of a fungus of either the order Agaricales (in which falls the common field mushroom and others—see agaric) or the order Boletales (in which the cep or king bolete is best known). But in everyday usage the word can be used very generally, applying to any edible fungi; and is certainly taken to include any edible fungus of the same general shape as a mushroom proper, having a round cap and usually a stalk. Some kinds of mushroom which grow out of the side of a tree trunk have almost no stalk. For example the oyster fungus, often called the oyster mushroom, has a very short, offset stem. And there are also stemless fungi attached directly to a tree trunk and known collectively as bracket fungi. But even these can be called mushrooms. Any fungus of obviously non-mushroom shape, such as the puffball, morel, or truffle, is usually referred to under its own name; but the general remarks on mushrooms here refer to these equally.