Rhizochromulina

Rhizochromulina is an unusual genus of marine heterokont algae, with one species, R. marina. They are colored amoeboids with a single flagellum, and produce distinctive spindle-shaped zoospores. These have a cell structure typical of the axodines, and in particular Rhizochromulina is considered to be the closest relative of the actinodines, including various colored algae and colorless heliozoa. Before it was studied in detail, Rhizochromulina was included among the superficially similar golden algae in the order Chrysamoebales, but these produce zoospores which are similar to flagellate golden algae in form.