Euglenales

Phacus (fake-us) (suecicus), the genus Phacus is one of the genera of autotrophic euglenids, distinguished from Euglena a by being flattened or twisted and rigid. Most species are quite flat and twisted, but a few are almost cylindrical and have a slight surface fold. The genus is common in freshwater ecosystems, in muds and associated with detritus. Phase contrast.

Phacus, flattened euglenid flagellate with numerous disc shaped chloroplasts, and anterior red eyespot. The outer region of the cell is called the pellicle and this has a ridged appearance. From Lake Donghu, China. Differential interference contrast micrograph.

Phacus, found in Obsidian Creek, is a flattened, stiff euglenid with numerous small disk-shaped chloroplasts. As with Euglena, there is an eyespot that controls the direction of movement. The clear circular region is the nucleus.

Portrait of Phacus longicauda v. tortus, a large euglenoid flagellate with rigid pellicle twisted about half a revolution about its long axis. Many small discoid chloroplasts. Prominent longitudinal pellicular ridges. Red stigma. Central circular paramylon body (not well seen here). This individual has shed its flagellum. From freshwater pond near Boise, Idaho. Brightfield.

Portrait of Strombomonas acuminata a loricate euglenoid flagellate. Lorica in this species is brownish with a tapering neck and the posterior drawn out to a tapering point. Single flagellum emerges from aperture in neck. Debris adheres to the lorica in this species. Cell body does not fill lorica.Prominent stigma and discoid plastids.From freshwater pond near Boise, Idaho. Oblique illumination.

Euglenopsis zabra Norris, 1961. Cells colourless, cylindrical, usually with a more or less pointed posterior end. A wide shallow groove extending only a short distance is present at the anterior end of the cell. A single flagellum approximately as long as the cell emerged from the center of the groove. The flagellar pocket is small and very difficult to see. Striations are not evident on the periplast. The protoplast contained a large number of small granules and one very large golden granule that was probably an ingested food body. The nucleus is near the base of the flagellar pocket. The cells are only slightly metabolic and swim slowly, rotating and with the flagellum directed forward. Length of cell 18 to 23. microns, width 5 to 10 microns

Euglena ehrenbergii. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using phase contrast optics.   This work was supported by the Australian Biological Resources Study.

Euglena ehrenbergii. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003.  This work was supported by the Australian Biological Resources Study.

Euglena ehrenbergii. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using differential interference contrast optics. This work was supported by The Australian Biological Resources Study

Phacus agilis. Cell observed in freshwater habitats in the vicinity of Broome, Western Australia in September 2003. This image was taken using differential interference contrast optics.   This work was supported by the Australian Biological Resources Study.