By Harold McGee
Truffles are the fruiting bodies of species in 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.