Crucigenia

Crucigenia is a genus of green algae in the family Scenedesmaceae. It is widespread, but not often abundant, in freshwater habitats (as phytoplankton) around the world.

==Description== Crucigenia consists of colonies of four cells in a flattened square shape, up to 16 μm in diameter; occasionally these colonies may be joined to form 8- or 16-celled compound coenobia. Colonies are embedded in a thin, gelatinous envelope. Cells are triangular, ovoid, ellipsoid, or rectangular, forming a small hole in the center of the colony. Cells are uninucleate (with a single nucleus) and with a single, parietal chloroplast that may or may not contain a pyrenoid.