Tuber fuscum Corda (1837), in (Corda) Zobel Icones Fungorum 1: 25, t. 7 f. 298
Tuber alatum Corda (1854), in (Corda) Zobel Icones Fungorum 6: 76, t. 20 f. 141
Tuber lapideum Mattirolo (1887), Mem. R. Acad. Sc. Torino Ser. II, 38: 378, t. 1 f. 1,2,10, t. 2 f. 1-6
Ascomata: hypogeous, irregular in form, lobed, sulcate, sometimes flattened, with a conspicuous basal cavity, 1-4 cm in size (as an exception 6 cm), brown-orangish just when removed from the earth, then ochre or brown, smooth in appearance but minutely papillose under the lens
Gleba: hard, solid, brown-ochre, reddish brown at maturity, marbled with yellowish, branching veins which often arise from the base and are radially arranged.
Odour: more or less intense according to truffe ripen, tuber-like, sometimes garlicky, unpleasant at full maturity. Easily detectable by truffle dogs, the truffle beetle (Leiodes cinnamomea) and truffle flies (Suillia spp.).
Taste: faint, tuber-like
Calcareous soils, associated with deciduous trees and conifers. Tuber excavatum is a very common truffle. They ripen throughout the year if conditions are favorable. We find ripe truffless under oaks in summer and winter, up to 1600 metres of altitude.
Tuber excavatum Vittadini var. sulphureum G. & L. Riousset has a sulfur yellow peridium. It ripen in spring.
Tuber excavatum Vittadini forma monticellianum (Vittadini) Ceruti; = Tuber lapideum Mattirolo, has an ochre peridium with shades of gray and green olive and a purplish brown gleba.
Tuber fulgens Quélet 1880 (= Tuber excavatum subsp. fulgens (Quélet) Fisher 1897) is similar to Tuber excavatum but most of spores are globoses.
Asci: subglobose to ellipsoid, sessile or short-stalked, 65-110 x 60-80 µm, 1-4 (-5)-spored (usually 3-4-spored).
Ascospores: 30-50 x 22-32 µm excluding ornament, size variable depending on number of spores in the ascus, Q range = 1,36-1,60, ellipsoid, yellow, yellow brown at maturity, translucent, ornamented with a coarse irregular reticulum with meshes 4-6 µm high, up to 22 µm long, 2-4 across width of spore.
Peridium: 200-360 (-500) µm thick, yellowish in section, composed of agglutinated, interwoven, thick-walled hyphae, larger near the surface and forming subglobose cells of 10-15 µm, in a superficial layer 50-70 µm thick