Abstract
Tuber luomae, a new truffle species known only from the Pacific Northwest, USA, is distinguished by spiny, non-reticulate spores and a two-layered peridium - the outermost layer (pellis) consists of inflated, globose to subpolygonal cells and the inner (subpellis) of narrow hyphae. ITS sequence analyses show that it has phylogenetic affinity to other Tuber species in the Rufum clade. The only other members of the Rufum clade with a strongly developed peridiopellis of large, inflated cells are the southern European T. malacodermum and T. pustulatum and the northern Mexican T. theleascum. We find it interesting that this peridial structure that is uncommon in the Rufum clade has been found in geographically disjunct species.