Diatoms by Shape | Mendota Diatoms

Diatoms with radial symmetry. Are usually circles, discs, or cylinders, or spheres, but can also be star-shaped.

Diatoms without a raphe (the line-like movement system often found at the center or edges of the diatom)

Diatoms with a single raphe on one of its valve faces, often as a solid central line.

Bilaterally symmetric diatoms with two raphe systems, often meeting at the center.

Asymmetrical diatoms with two raphe, which usually meet in the center of the valve face or one on each face

Bilaterally symmetric diatoms with a highly developed raised raphe system that follows the perimeter of the valve

Thin, symmetric diatoms that often have a well-developed raphe system on the perimeter of each valve face.

Symmetrical over the apical axis, these diatoms often have a unique "mustache" appearance.

A collection of things that might be found in samples but which aren't freshwater diatoms