Abstract
Based on morphological data and ITS nrDNA sequence analyses, we formally describe two species from the phylogenetic grouping ‘Martin sp. 10’ as Pisolithus thermaeus sp. nov., endemic to New Zealand, and P. tympanobaculus sp. nov. from Australia. All Pisolithus species in New Zealand are restricted in distribution to geothermally active areas, in ectomycorrhizal association with Kunzea tenuicaulis. In Australia species occur in a broad range of habitats in association with Eucalyptus or Acacia species; and in New Caledonia species form associations with various Myrtaceae or an Acacia species. The distribution ranges of Pisolithus albus, P. marmoratus and P. croceorrhizus are extended to include the Kimberley and Top End regions of northern Australia. We also confirm that neither P. arenarius, nor P. tinctorius sensu stricto, nor P. arhizus are currently known to occur in Australia or New Zealand. The long-used but never formalized combination Pisolithus albus (Cooke & Massee) Priest is validated here and nomenclatural knots relating to three different usages of the name Pisolithus tinctorius are unraveled and suggestions made for their resolution.