Erysiphe chloranthi is the only powdery mildew species (Erysiphaceae) found on Chloranthus plants belonging to the family Chloranthaceae. This species has long been known to be present in Japan and Korea and is hence regarded as endemic to East Asia. Examination of seven Korean specimens revealed detailed morphological characteristics of the holomorph of this species. Short foot-cells of conidiophores are proposed as key characteristics that differ from related species. Sequences of the internal transcribed spacer regions and large subunit gene retrieved from four Korean samples confirm the phylogenetic position of this species within the Erysiphe aquilegiae complex. These data may help elucidate the identity of this species and clarify the ambiguity of the E. aquilegiae complex.