Basidiomycete Quambalaria cyanescens (Quambalariaceae, Microstromatales, Exobasidiomycetidae, Exobasidiomycetes, Ustilaginomycotina, Basidiomycota) was known earlier mainly as a symbiont of plants of the genera Eucalyptus and Corymbia on the Australian continent. Now it was found in association with silver birch in the territory of Moscow and Moscow Region. Q. cyanescens is revealed most frequently on the surface and inside thyrsus, in pollen samples, and less frequently on the surface of leaves and shoots. DNA profiling provided the evidence for the phylogeographical structure of the species. Further studies revealed Q. cyanescens in the samples collected in Cheboksary (Russia) and in Nessebar (Bulgaria). The list of regions where Q. cyanescens was found in association with birch steadily extends and embraces different geographical zones. The structure of the septal apparatus is of great importance for basidial fungi taxonomy. The mycelium of our isolates contained dolipore septa with thickenings around the pore channel characteristic for the type strain of Q. cyanescens. Accumulated data prove close association between birch and Q. cyanescens that warrant further investigation
