Bacillaria is a diatom genus in the family Bacillariaceae.

Cells are elongated and motile, sliding along each other, in stacked colonies.

Two large plate-like chloroplasts are present, one near each end of the cell.

Fibulae are strong, and the valve surface is covered in transverse parallel structures called striae.

The cells of Bacillaria moved next to each other in partial but opposite synchrony by a microfluidics method.