Closterium is a genus of Desmids (order, Desmidiales). Desmids are characterized by their unique, delecate, and  symmetrical cell walls, composed of cellulose.

Centric Diatom

In a sample of saltwater, I discovered this centric diatom. There are two basic morphological types of diatoms: Pennate (rods), and Centric (round). All of the diatoms previously mentioned on this blog were pennate forms.


Euglena has a stiff cell membrane known as a pellicle, which can be seen easily in these two photos. Euglena’a pellicle is composed of protein strips that wrap around the cell. Towards the left side of the cell in the featured photo is a single red eyespot. Around the middle of the cell is an elongated ring-like structure called a paramylon. The paramylon was briefly mentioned in an earlier post regarding Phacus.

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Trachelomonas is a genus within Euglenaceae, a family including Euglena. Trachelomonas differs from most other Euglenids as it possesses a shell-like structure called a lorica. This lorica contains ferric hydroxide, which gives it a redish coloring. At one end of the lorica is a small aperture from which the cell’s flagellum may emerge. Small spines are also present outside the lorica.

A relatively long flagellum can be seen extended from the green cell (left).

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Here we see Euglenoid cells in a dormant stage of their life cycle known as palmella. Each green cell is contained within a gelatinous mucilage. A few cells can be seen dividing.

Colonial Flagellates

Rather than remaining solitary, some flagellates will form colonies. A classic example of this are the Synura Uvella featured in the photo above. The genus Synura is included among the Chrysophyta (Golden Algae). Clearly seen extending from one cell is a single flagellum.

Please be aware the the Chrysophyta are NOT an actual taxon; the genus Synura is included in the class Synurophyceae

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