The truffle genus Pachyphloeus in the U.S. and Mexico: phylogenetic analysis and a new species

A molecular analysis of LSU and ITS portions of rDNA from Pachyphloeus ascocarp collections in the United States and Mexico gives strong bootstrap support for four clades within the genus. Two clades include collections from Iowa and Mexico. From one of these, a new species of Pachyphloeus, is described from oak woodlands. Pachyphloeus marroninus is distinguished from other species of Pachyphloeus by the combination of a reddish brown peridium with low, polygonal warts, a solid, white gleba, narrowly clavate asci, and spore spines that are coarse with tips free from the perisporium at maturity. Molecular analyses support the close relationship of this species from Iowa and Mexico, but the variations in sequences may indicate a cryptic species complex.