The "black truffle" (Tuber melanosporum). Specimens can be found in late autumn and winter, reaching 7 cm in diameter and weighing up to 100 g. Production is almost exclusively European, with France accounting for 45%, Spain 35%, Italy 20%, and small amounts from Slovenia, Croatia and the Australian states of Tasmania and Western Australia.
The mycelia of truffles form symbiotic relationships with the roots of several tree species including beech, poplar, oak, birch, hornbeam, hazel, and pine. They prefer argillaceous or calcareous soils which are well drained and neutral or alkaline. Truffles fruit throughout the year, depending on the species and can be found buried between the leaf litter and the soil.