TUBER MAGNATUM Pico
Melethemata inauguralia. De fungorum generatione et propagatione 79, without illustration (1788)
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Synonyms:
Tuber griseum Persoon (1801), Synopsis Methodica Fungorum 127
Tuber griseum Persoon: Fries (1823), Systema Mycologicum 2, Pt. II: 292
Macroscopic characters:
Ascomata: hypogeous, irregular in shape, lobed, gibbous, sometimes flattened, 2–6 (–15) cm across, smooth in appearance but finely papillose under a hand lens, pale ochre, sometimes with greenish tints.
Gleba: firm, solid, with a soapy texture; whitish at first, becoming pale yellow, ochre-brown or reddish brown, often with flesh-red spots; marbled with numerous thin, whitish, meandering, anastomosing veins.
Odour: intense, complex; a distinctive blend of methane gas, fermented cheese and garlic.
Taste: intense, pleasant, garlicky.
Habitat:
Marly calcareous soils with high macroporosity, typically in well-drained alluvial plain forests. Soils are generally grey and stones are scarce. Always found in shady woodland with limited temperature fluctuation. Tuber magnatum is harvested in areas of dense vegetation, free of “burn”, with a microclimate characterised by a short dry season. Rainfall in July and August is essential for fruiting. The season is very short, from late September to late November, varying by region. Associated tree hosts include poplars (Populus), willows (Salix), hazels (Corylus), oaks (Quercus) and lindens (Tilia). The Italian white truffle has not yet been successfully cultivated.
Notes:
Tuber magnatum is the most expensive truffle in the world, fetching prices in excess of 3,000 € per kg. It is harvested mainly in Italy and has so far only been recorded in Italy, Croatia (Istria), Slovenia and Hungary. It must be eaten raw; once cooked, it loses all its aroma.
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Microscopic characters:
Asci: subglobose to ellipsoid, sessile or short-stalked, 60–90 × 50–60 µm, 1–3 (–4)-spored (usually 2-spored).
Ascospores: 20–33 × 20–30 µm excluding ornament, size variable depending on the number of spores per ascus, Q range = 1.05–1.33, subglobose to broadly ellipsoid, pale yellow to ochre-yellow at maturity, ornamented with a coarse irregular reticulum 4–5 (–8) µm high, meshes variable, usually 2–3 across the width of the spore.
Peridium: pseudoparenchymatous, composed of subglobose to ovoid cells.
 | Antonio Rodríguez trufamania@gmail.com antonio@trufamania.com |