On Food and Cooking

the genus Tuber, of which there are a handful
of commercially important ones. They’re
typically a dense, knobby mass, ranging from
walnut-to fist-sized or larger. Unlike
mushrooms, truffles remain hidden
underground. They spread their spores by
emitting a scent to attract animals —
including beetles, squirrels, rabbits, and deer
— which find and eat them and spread the
spores in their dung. This is why truffles have
a musky, persistent aroma — to attract their
spore spreaders — and why they’re still
gathered with the help of trained dogs or pigs
or by spotting truffle “flies,” insects that
hover over truffled ground and lay their eggs
there so that the larvae can burrow down and
feed on the fungus.
Truffles grow only in symbiosis with trees,
usually oaks, hazels, or lindens, so cultivation
means finding or planting a forest, with
significant harvests coming only after a
decade or more. The Périgord region in France