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 brumale Vitt. (Winter)

Usually globose in sharpe or a little lobed, with black or dark iron peridium, with very close, evident warts, hollow on the top and with longitudinal grooves. Its gleba is dark brown or greyish black with large white veins. Spores are herringbone. It can easily become bigger than a hen's egg. It can be found in autumn and early winter under oaks and hazels.

It is widespread in the Centre South of Europe. Its smell and its taste are more or less strong but pleasant (in particular in its variety moschatum Ferry) and make so that it is normally consumed even if it is mush less appreciated than Tuber melanosporum with which it is sometimes confused.