 From the 19 downy mildew producing genera, "Hyaloperonospora" has been grouped with "Perofascia" in the brassicolous downy mildews.In the group of downy mildews, "Hyaloperonospora" is the third biggest genus.The most famous species in the genus is the "Hyaloperonospora parasitica", or also known as "Hyaloperonospora arabidopsis".