Euglena

Euglena is a genus of microscopic, one-celled organisms in the Protista kingdom. There are about 150 species of euglenas. They live in fresh water, and are especially common in warm seasons when they may form a green scum on the surfaces of small ponds or drainage ditches.

Euglenas have spindle-shaped bodies, and range in size from 1/1000 to 1/100 of an inch (0.025 to 0.254 millimeter) long. Most species are green because they contain chlorophyll which allows them to produce food through photosynthesis for themselves, as well as serve as primary producers for aquatic ecosystems. Some species also eat tiny particles of living matter. Euglenas use a flagellum (a whiplike appendage) that sticks out from the body, to move and are thus categorized as flagellates. Euglena are commonly foundly infreshwater streams and ponds and make excellent specimens for study. They reproduce rapidly and can be studied under an ordinary microscope.