11, see text 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.

[1] Dead Hydrosera create siliceous oozes.

[2] Hydrosera grows in the streams of southern coastal areas and tropical islands.