Picoa melospora G. Moreno, J. Díez & Manjón, Bull. sem. Féd. Assoc. Mycol. mediterr., 18: 88 (2000)
Ascomata: hypogeous, single to gregarious, subglobose, 1–2(–3) cm in size, reddish brown to dark brownish almost black, cracked, warted. Warts irregular in form and size, flattened.
Peridium: 150–250 µm thick, composed of cylindrical, hyaline, agglutinated, interwoven hyphae 4–5 µm diam, becoming pseudoparenchymatous and pigmented towards the surface, the outermost 40–70 µm composed of subangular, pigmented, thick-walled cells.
Gleba: firm, solid, whitish at first, becoming light-brown, dark-brown at maturity, marbled with meandering, white and dark-coloured veins.
Tuber melosporum grows in calcareous, clayey, alkaline soils, associated with Pinus spp. and Quercus ilex, with no presence of Helianthemum spp, from May to June.
Tuber melosporum is distinguished from all others Tuber species by its smooth spores.
Asci: inamyloid, ovoid to broadly clavate or pyriform, , with stalk up to 60 µm long, 70–90 x 50–60 µm excluding stalk, 1–4 (–5)-spored.
Ascospores: 26–50(–58) x 17–30 µm, size variable depending on number of spores in the ascus, Q range = 1,24–1,82, ellipsoid, smooth, thick-walled, hyalines at first, yellow ochre at maturity.