Truffle describes a group of edible mycorrhizal (symbiotic relationship between fungus and plant) fungi.
Truffles are found anywhere from two to 16 inches (5 to 40 cm) below the ground, usually in a circular formation about four to five feet (120 to 150 cm) from the base of an oak tree.
A number of varieties exist including desert truffles found in the Middle East and the Mediterranean.
The ascoma (fruiting body) of truffles is highly prized as food.
Because of their high price and their pungent taste, truffles are used sparingly.