Cosmarium angulatum f. majus (Grunow) W.B.Turner 1892

    Cells medium sized, 1.3-1.5 times longer than broad; cells measures 62-70 µm in length and 38-42 µm in width. Cells moderately constricted at the center, sinus linear and slightly open at the posterior end, isthmus 13-15 µm. Semicells hexagonal, lateral margins straight or slightly retuse; apex truncate or slightly retuse. The apical and basal angles of the semicell broadly rounded and cell wall smooth.