Puccinia passerinii (Pucciniales) on Thesium ebracteatum in the Biebrza National Park - new data on its distribution in Central Europe

This work provides a morphological description of a parasitic fungus Puccinia passerinii Schroet. discovered in the Biebrza National Park on bractless toadflax Thesium ebracteatum Hayne, a host plant listed in Appendix II of the Habitat Directive and strictly protected in Poland. Puccinia passerinii was recorded in 1916 within the borders of current-day Poland, however, owing to a lack of herbarial materials it was not included into the checklist of Polish microscopic fungi. This work is the first report, after 100 years, on the appearance of this species in Poland, which enlarges the list of microfungi in this country and particularly in the Biebrza National Park. Moreover, a common parasite of rust fungi – Sphaerellopsis filum (Biv.) B. Sutton is reported for the first time on P. passerinii.