Truffles differ mainly in terms of their morphological properties, such as shape, size and colour, the ornamentation of the peridium, the appearance of the gleba, and their smell and flavour.

The various species are determined in the laboratory by identifying the spores, or by means of bio molecular analysis techniques. Currently 63 species of fungus are classified as Tubers. Nine of the 25 which grow in Italy are considered edible, and of these the 6 most commonly found on sale are:

Tuber melanosporum Vitt. (Fine black truffle)

Globose shape, sometimes lobed, with brown to black peridium, with close warts, hollow on their tops and crossed by longitudinal grooves. Its gleba is brownish grey or reddish black in colour, striped with thin, light, intensely branched veins. Spores are herringbone. It can reach zhe size of a big apple or grow even bigger.

It is gathered during the whole winter period and in particular in the first months of the year, especially under oaks, hazels and hophornbeams. It is frequent in Italy and Spain but it is gathered and appreciated in France in particular. Its specific taste and its aromatic smell make it very much appreciated in cookery. The French consider it the best and therefore the most valuable of the "black". It is preferably eaten a short cooking.

Definitions of its aroma by some authors: "odour of a slightly rotten strawberry". In the remarks: "very good at first, similar to strawberry, then it becomes bitter, heavy, acraid, but not unpleasant" (Vittadini); "grateful aromatic smell" (Mannozzi); "odor aromatic specificus" (Ceruti); "typical and pleasant" (Montecchi); "intense odour" (Pacioni).