What is "tuber melanosporum"

Truffle \Truf"fle\ (?; 277), n. [OF. trufle, F. truffe; akin to Sp. trufa, tartufo; of uncertain origin; perhaps from L. tuber a tumor, knob, truffle. Cf. Tuber, Trifle.] Any one of several kinds of roundish, subterranean fungi, usually of a blackish color. The French truffle ( Tuber melanosporum) and the English truffle ( Tuber [ae]stivum) are much esteemed as articles of food.

Truffle worm (Zo["o]l.), the larva of a fly of the genus Leiodes, injurious to truffles.

Tuber melanosporum, called the black truffle, Périgord truffle or French black truffle, is a species of truffle native to Southern Europe. It is one of the most expensive edible mushrooms in the world.