A new species of hypogeous Pezizales, Mattirolomyces tiffanyae, is described and illustrated. Its asci are typically three-spored, an unusually small number in the non-Tuber Pezizales. Ascus septal pore ultrastructure consists of a uni- or bi-convex band, which suggests an affinity with the Pezizaceae. Secondary spore-wall development is similar to that of Peziza, and several species of hypogeous Pezizaceae.