Thekopsora ostryae (Pucciniastraceae, Pucciniales), a new species from Gansu, northwestern China

• A new rust species, Thekopsora ostryae, was found in Gansu, China on leaves of Ostrya japonica.
• Morphological and molecular methods delimited a new taxon in Thekopsora.
• Thekopsora ostryae is characterized by well-developed lingulate uredinial ostiolar cells with sparsely echinulate surface.

Thekopsora ostryae, a new rust fungus on leaves of Ostrya japonica collected from Gansu Province was described. Morphological examination using light and scanning electron microscopy showed that this new species is distinct from other species of Thekopsora in the characteristics of ostiolar peridial cells of uredinia and the spinules on the surface of urediniospores. Analyses of the ITS1-5.8S-ITS2 and 28S rRNA gene partial sequences showed that T. ostryae could be a distinct lineage in the genus Thekopsora.