A truffle is the highly aromatic, subterranean, fruit of specialised fungi growing on the roots of specific host trees. Truffle fungi establish a relationship with a host tree, known as a mycorrhizal symbiosis. The fungi live externally on and around fine tree roots and develop a vast network of mycelium in the soil, formed by microscopic filaments called hyphae.
Active mycelium searches for and returns nutrients and enhanced water intake to the tree. In return the tree provides the fungus with sugars and starches from the process of photosynthesis. The fruit body (truffle) is formed when compatible mycelium mating types fuse under the right conditions, and depending on the species, this may occur in spring, summer, and autumn.
The French Black Truffle, Tuber melanosporum, is the most studied and farmed species in Europe, Australia, USA, New Zealand, Chile, South Africa, and other locations around the globe. When fully ripe, the French Black truffle has an intense, pungent aroma and earthy flavour. Its exterior (peridium) is dark and rough, and the interior (gleba) is dark in colour with creamy white veins.
This truffle is endemic to specific parts of Europe generally growing between elevations of 100-1000m (300-3600 feet).
Typical climate zones are Mediterranean, Oceanic and Continental.
Natural habitats are deep, well-draining, stony, calcareous, high pH (7.5-8.3) soils, on warm, exposed sites.
When growing this species in other parts of the world, such as the southern hemisphere, farmers generally need to modify soils, applying what has been learned from scientific studies of natural truffle grounds, field research and the ecology of the truffle.