Two novel Tuber species (Tuberaceae, Pezizales) from southwestern China based on morphological and molecular evidence

Based on morphological and molecular phylogenetic analyses, two new species, Tubermarroninum and Tuberconditum, belonging to the Latisporum group, were described from Yunnan province of southwest China. Morphologically, Tubermarroninum is distinguished from other Latisporum species by whitish and glabrous ascomata and a two-layered peridium, measuring 150-200 µm in total thickness, with an outer layer ranging from 40-60 µm. Tuberconditum is diagnosed by its thinner peridium (120-200 µm) and larger ascospores (49-66.5 × 34.5-60 μm in one-spored asci). According to the outcome of the ITS rDNA sequence analysis, the species of T.marroninum and T.conditum each form a distinct and well-supported group within the Latisporum group, respectively.