Pisolithus hypogaeus sp. nov.: A hypogeous representative of the genus Pisolithus from Western Australia

Pisolithus hypogaeus, the first record of a Pisolithus species with a hypogeous habit, occurs in coastal south-western Australia in association with eucalypt ectomycorrhizal hosts on sandy soils. Ribosomal DNA (rDNA) sequencing shows that P. hypogaeus lies within a lineage of other brown- and echinulate-spored Pisolithus spp., and is most closely related to two undescribed epigeous Pisolithus species from Australia.