Russulaceae in American Samoa: new species and further support for an Australasian origin for Samoan ectomycorrhizal fungi

Two new species from the Russulaceae, Lactifluus aurantiotinctus and Russula pallidirosea, are described from American Samoa. Based on analyses of nuc rDNA internal transcribed spacer region barcodes (ITS), L. aurantiotinctus has an affinity to subgenus Lactariopsis and strong phylogeographic ties to Papua New Guinea. The ITS data indicate that Russula pallidirosea has an affinity to subgenus Heterophyllidia and suggest that it also has phylogeographic ties to Australasia. Both species were associated with the ectomycorrhizal tree Intsia bijuga.