Stramenopile

Four common forms of Blastocystis hominis. Clockwise from top left: vacuolar, granular, amoeboid, and cyst forms.

The Stramenopile group is a recently recognised informal monophyletic grouping into which a number of microscopic parasitic organisms from the superkingdom Protista and a number of diatoms and brown seaweeds are placed.

Labyrinthulomycota, Hyphochytriomycota, Phytophthora, Aphanomyces, Bremia, Pernospora and the Oomycetes are also protists that form part of the Stramenopile group. The Stramenopile group (or clade) is a sister group of another multicellular clade which includes Plantae, Animalia and Fungi.