Tuber excavatum

Under broadleaf trees, preferring calcareous soils, with very irregular, lobed ascomata 1.5 to 4 cm in diameter, with a smooth ochre-brown surface, a pinkish-brown gleba with whitish to yellowish veins suggesting a radial arrangement from the base, an intense alliaceous odor in mature specimens, and a mild taste.

Hyphae of the outer peridium pseudoparenchymatous, 10 to 15 µm in diameter, rounded to polyhedral, thick-walled, with abundant brownish intracellular pigment.

Hyphae of the inner peridium filamentous, thick-walled, more hyaline, profusely branched, and densely interwoven.

Asci subglobose to ellipsoid, sometimes with a short pedicel, 70 to 100 µm long, 65 to 75 µm wide, and usually containing 2 to 4 spores inside.

Ascospores ellipsoid, with ridges 4 to 6 µm high, yellowish under the microscope, 30 to 45 µm long excluding ornamentation, 20 to 35 µm wide, with ridges forming a reticulum of large, irregular polygonal alveoli, with only 2 to 4 alveoli across the widest diameter of the spore.