[2] Members of this order are ecologically widespread and are found in freshwater, marine, and terrestrial habitats from the Arctic to the Antarctic.

[4] The ultrastructure of Prasiolales is unique and includes cells with four flagella, with their basal flagellar apparatuses in a counterclockwise orientation.

Molecular phylogenetics studies have found that coccoid algae of very simple morphology, such as Stichococcus, also belong to this order.

[6] Genera of uncertain placement to family include:[1] Molecular phylogenetic studies have shown the following relationships (not all genera are included):[7][8][9][10][6] Raphidonema/Koliella pro parte Pseudochlorella Raphidonema/Koliella pro parte Ekerewekia Gloeocystis polydermatica Edaphochlorella (syn.

Chlorella mirabilis) Prasiolaceae Pseudomarvania Stichococcus Desmococcus Protostichococcus Deuterostichococcus Tritostichococcus Diplosphaera Tetratostichococcus Pseudostichococcus