an ascomycetous. fungus with a fleshy, tuberous subterranean fruiting body. Most truffles belong to the order Tu-berales. They grow in forests as saprophytes or form mycorrhizae with tree roots. Some of the fruiting bodies resemble marble in cross section.
There are a few edible species of truffles. The most valuable is the very aromatic Tuber brumale, which is black and warty on the outside and dark gray or reddish black with light veining on the inside. Tuber brumale grows in oak and beech groves, mainly in southern France and northern Italy, where it has great commercial value. The species Choiromyces meandriformis, whose light-fleshed fruiting body resembles a potato in form and size, grows in the forests of Western Europe, the western USSR, and Moscow Oblast. Truffles of the genus Terfezia, which belong to the order Plectascales, include a number of edible species but are of less value than Tuber brumale. They grow in Southern Europe, North Africa, and Southwest Asia, as well as in the Azerbaijan and Turkmen SSR’s of the USSR.
Inedible basidial fungi of the genus Scleroderma of the order Gastromycetes, whose fruiting bodies are in the form of rounded or elongated yellow tubers 3–10 cm long, are sometimes erroneously called truffles. The fungi are found in forests and parks. Their fruiting bodies have an unpleasant odor and initially are solid, with a black interior and light veining; the interior later disintegrates.