Spindle shaped cells forming star-shaped colonies. Cell shape is variable, large cells are rostrate, smaller cells have shorter prolongations and small cells may be lanceolate. Valves have one labiate process and a narrow sternum that varies in shape and size. Cells have two chloroplasts, one against each valve. Common as epiphyte on Melosira arctica.
Apical axis measures 13-96 µm, transapical axis 2,5-4 µm. 25-27 transapical stria in 10 µm
Throndsen J. Hasle G.R. and Tangen K. 2007. Phytoplankton of Norwegian coastal waters. Almater Forlag AS. 341 pp