A genus of green algae (sometimes alternatively regarded as protozoa, class Phytomastigophora) in which the cells occur in spherical, motile colonies (coenobia) of 500 to many thousands of cells, according to species. The individual cells resemble those of Chlamydomonas species. The genus shows considerable complexity in morphology and sexual reproduction. Species are found in various aquatic habitats: puddles, ponds, ditches, lakes, etc.
Subjects: Plant Sciences and Forestry.