angia were 31.2-46.8 × 23.4-33.2 μm in range, 39.6 ± 4.1 × 28.3 ± 2.8 μm in average ± standard deviation, l/b ratio approximately 1.40, with papillae about 3.6 μm high, and pedicels 0.9- 5.8 μm long. Oogonia were spherical, 25.0-32.5 μm in range with an average of 28.2 ± 2.3 μm in diameter.Antheridia were predominantly paragynous, globose to ovoid, 8.8-13.8 × 7.5-10.0 μm with an average of 10.9 ± 1.2 × 9.2 ± 1.1 μm. Oospores in the oogonia were aplerotic or plerotic, and 20.0-25.0 μm in diameter with an average of 23.5 ± 1.5 μm. Pathogenicity of the isolate was confirmed on detached leaves of fatsia. The disease was observed only in April and May of 2003 when the weather was unusually wet. It then diminished with increase of temperature in the year and did not appear again on the same plants in 2004. Thus, the fungus appeared to be a relatively weak pathogen of fatsia.