A new species of Melampsora rust on Salix elbursensis from Iran.

Summary A rust fungus was found causing stem cankers on 1- to 5-year-old stems of Salix elbursensis in the north west of Iran. The rust also forms uredinia on leaves and flowers of the host willow. Light and scanning electron microscopy revealed that the new rust is morphologically distinct from several Melampsora species occurring on the willows taxonomically close to S. elbursensis, but indistinguishable from Melampsora larici-epitea. Examination of the internal transcribed spacer (ITS) region of the ribosomal DNA suggested that the rust fungus is phylogenetically close to Melampsora allii-populina and Melampsora pruinosae on Populus spp. Based on both the morphological characteristics and the ITS sequence data, the rust is described as a new species - Melampsora iranica sp. nov. [ABSTRACT FROM AUTHOR]