Near this group of live oaks your dog may be captivated by a pungent fragrance.  At the base of the trees, there are patches of ground that have no plant life.  If your dog digs below this “burned ground”, you will find that the emanation is coming from the most expensive fungus in the world: Tuber melanosporum, a hypogeal (subterranean) ascomycete. This species of truffle is the rarest and for this reason is called diamant noir (black diamond).  The truffle has been a delicacy for thousands of years.  Theophrastus described the truffle as a “rootless vegetable, generated by the heavy showers of autumn” and Pliny the Elder called it a “miracle of nature”.  The area surrounding Mont Ventoux has been prized cropland in France since the reign of Francois I (16th century) who was enamored by them while in captivity in Spain.  Truffle production in France peaked late in the 19th century.  A rural exodus and the industrial revolution, followed by two world wars, caused the yield to plummet from 1587 tons in 1868, to 36 tons in 1950. The truffle thrives on calcareous soil with a pH slightly greater than 7 and moderate precipitation.  It originates from a mycelium that lives in mycorrhizal association with the roots of a tree, for example a live oak, hazel tree, or olive tree.  This permits the fungus to obtain carbohydrates and, in exchange, the tree receives minerals, which allow it to better support the limestone content of the soil.  These exchanges eventually trigger the formation of yellow brown clubs on the mycorrhizae.  When the “trufflette” enlarges, it becomes independent and the truffle takes in nutrients via tufts of mycelia at the tip of the peridium (covering of the spore-bearing organ). The aromatic substance depends on ascocarp maturation, which is signaled by an increase in fatty secretions and the formation of brown-colored reproductive organs.  The maturation of the truffle and thus, its harvest time, occurs around December to February.   --Y. Zarbalian