The cells exhibit an elongated, fusiform, or rectangular shape when viewed from the girdle side. They tend to form chains by overlapping the ends of adjacent cells, with chains frequently consisting of 20 cells or more. These cells have an open, distinctly pointed, narrow shape, and they are mostly marked with striations. The structure of the striae on these cells is akin to those found on the valves. The raphe system distinguishes them from Nitzschia. These organisms have bilateral symmetry and possess silica cell walls known as frustules. They are capable of both sexual and asexual reproduction.