Panellus stypticus fruits widely in Northern Hemisphere temperate forests b
ut has also been collected in Alaska, Costa Rica, Australia and New Zealand
. Previous studies established that there was a single biological species a
cross eastern North America, Russia, Japan and New Zealand. In order to exa
mine phylogenetic and biogeographical patterns within this species, the rib
osomal ITS1-5.8S-ITS2 region was amplified for 67 collections representing
North America, Eurasia, Australia and New Zealand and was sequenced for ten
exemplars selected from different geographical areas. The amplified ITS se
quence length for collections from New South Wales and Tasmania (Australia)
and New Zealand was consistent within each of these geographical areas but
varied between areas and was shorter than the ITS region for Northern Hemi
sphere collections. Length changes were due to a number of deletions. Delet
ed regions totaled 15 bp in collections from New South Wales, 29 bp from Ta
smania and 88 bp from New Zealand. Parsimony analysis based on ITS sequence
s produced two major clades, a Northern Hemisphere clade and an Oceanian cl
ade. The collection from New South Wales was basal to the Oceanian clade wi
th collections from Tasmania and New Zealand as derived. Restriction fragme
nt length polymorphisms based on BstZ I, Dra I and Hinf I identified severa
l biogeographically separated haplotypes within this species. In the Northe
rn Hemisphere, an eastern North American haplotype was separated from other
P. stypticus collections that extended from Pacific North America to Asia.
European collections also shared a unique haplotype. The presence of a nuc
lear ribosomal large subunit group I intron was inferred in all Northern He
misphere collections and in collections from New South Wales by length vari
ation of the PCR product and by sequencing of selected exemplars. ITS seque
nce data and the presence of a group I intron in the Northern Hemisphere an
d New South Wales collections provide evidence that Northern Hemisphere and
Southern Hemisphere distributions were connected through South East Asia.