Bacterial cellular morphologies

It has been suggested that Spiral bacteria be merged into this article. (Discuss) Proposed since December 2023.

It has been suggested that Coccus be merged into this article. (Discuss) Proposed since December 2023.

It has been suggested that Diplococcus be merged into this article. (Discuss) Proposed since December 2023.

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It has been suggested that Coccobacillus be merged into this article. (Discuss) Proposed since December 2023.

Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archaea).

Generally, the basic morphologies are spheres (coccus) and round-ended cylinders or rod shaped (bacillus). But, there are also other morphologies such as helically twisted cylinders (example Spirochetes), cylinders curved in one plane (selenomonads) and unusual morphologies (the square, flat box-shaped cells of the Archaean genus Haloquadratum). Other arrangements include pairs, tetrads, clusters, chains and palisades.