Phacus
Unlike Euglena, Phacus is not as common in stagnant environments, although it is found in a variety of habitats.
 
The genus mainly inhabits the plankton of swamps, ditches, and ponds throughout the United States and parts of Canada and Mexico.
 
Researchers have found fossils of cells very similar to Phacus that are as much as 60 million years old.