Heliozoa, commonly known as sun-animalcules, are microbial eukaryotes (protists) with stiff arms (axopodia) radiating from their spherical bodies, which are responsible for their common name. The axopodia are microtubule-supported projections from the amoeboid cell body, and are variously used for capturing food, sensation, movement, and attachment. They are similar to Radiolaria, but they are distinguished from them by lacking central capsules and other complex skeletal elements, although some produce simple scales and spines. They may be found in both freshwater and marine environments.
Desmidiales, commonly called the desmids, are an order in the Charophyta, a division of green algae in which the land plants (Embryophyta) emerged. Desmids consist of single-celled microscopic green algae. Because desmids are highly symmetrical, attractive, and come in a diversity of forms, they are popular subjects for microscopists, both amateur and professional.
The water net is a taxon of freshwater green algae in the family Hydrodictyaceae. Hydrodictyon does well in clean, eutrophic water, and has become a nuisance in New Zealand, where it has been recently introduced. The name water net comes from the mesh structure of their colonies, which can extend several decimeters; the scientific name also means "water net" in Greek.
Ankistrodesmus is a genus of green algae in the family Selenastraceae. It is one of the most common types of phytoplankton in freshwater habitats around the world. The name Ankistrodesmus comes from the Greek roots ankistron, meaning "cross", and desmos, meaning "bond".
Characium is a genus of green algae in the family Characiaceae. It is very commonly found in freshwater habitats, where it is attached to phytoplankton or zooplankton.
Chlainomonas is a genus of algae in the family Chlamydomonadaceae. They are found in freshwater habitats or on snow, where they are one of the main algae responsible for causing watermelon snow.
Desmodesmus is a genus of green algae in the family Scenedesmaceae. It is the only chlorophyll-containing organism known to have caused human infections in immunocompetent individuals. All known cases involved open injuries occurring in fresh water.
Golenkinia is a genus of green algae first described in 1894 by Robert Chodat. The genus is named for the Russian phycologist Mikhail Iljitsch Golenkin. Golenkinia species live in fresh water and are found around the world.
Lagerheimia is a genus of green algae in the family Oocystaceae. It is commonly found in freshwater habitats all over the world, although some species are rare and have only been recorded from Europe or the United States.
Polyedriopsis is a genus of green algae in the order Sphaeropleales. As of February 2022, it contained a single species, Polyedriopsis spinulosa. It is found worldwide in freshwater habitats as phytoplankton, but is rare.
Pseudoschroederia is a genus of green algae in the family Characiaceae. It is planktonic in freshwater habitats, and probably has a cosmopolitan distribution. The genus Pseudoschroederia was circumscribed by Eberhard Hegewald and Eberhard Schnepf in 1986. The genus was distinguished from the similar Schroederia by being heteropolar and differing cell structure. However, some authors do not consider the genera to be separate.
Radiofilum is a genus of green algae in the class Chlorophyceae. It is a freshwater genus; they are often found in soft, boggy or acidic waters.
Schroederia is a genus of green algae in the family Schroederiaceae. Schroederiaceae is a monotypic taxon; Schroederia is its only genus.
Sorastrum is a genus of green algae in the family Hydrodictyaceae. It is a component of the phytoplankton of freshwater ponds, lakes, and ditches. Sorastrum is common in tropical to temperate regions of the world, but due to its small size it is often overlooked.
Cosmarium is a large genus of desmids (Desmidiaceae), a group of green algae closely related to the land plants (Embryophyta). Members of this genus are microscopic and found in freshwater habitats around the world.
Staurodesmus is a genus of green algae, specifically of the Desmidiaceae.
Triploceras is a genus of desmid in the family Desmidiaceae.
Xanthidium is a genus of green algae, specifically of the Desmidiaceae.
Lanceola is a genus of green algae in the family Characiaceae, containing a single species, Lanceola spatulifera. It is found in freshwater habitats.
Echinosphaeridium is a genus of green algae, in the family Neochloridaceae. It is found in freshwater habitats, but it is very rare. It has only been recorded a few times since its original discovery in Sweden.
