A new downy-mildew of the Rosaceae : Peronospora oblatispora sp. nov. (Chromista, Peronosporales)

Peronospora oblatispora sp. nov., parasitic on Potentilla chrysantha, P. paradoxa, P. supina and Aphanes microcarpa, is described from 11 specimens collected in France, Korea and Romania. By its oblate conidia it differs morphologically from both P. sparsa and P. potentillae. The morphological discrepancy is supported by high genetic distances to the other two species and the larger insertions in ITS rDNA.