Hydrosera
Hydrosera is a genus of diatom described in 1858 by George Charles Wallich. Hydrosera exhibits valve margins resembling two superimposed triangles and the presence of a distinct rimoportula. Hydrosera also feature porefields at the three poles of one of the apparent triangles, which contain pseudocelli. Dead Hydrosera create siliceous oozes.
Hydrosera grows in the streams of southern coastal areas and tropical islands.