Tuberales

(truffles) An order of the *Discomycetes   in  which  the  ascocarps are formed underground and resemble tubers. It contains about 35 genera and 230 or so species, many of which are edible. Certain species are often found under particular trees, e.g. Tuber melanosporum (the European truffle), which grows under oaks. They are thus thought to be mycorrhizal.