Coccomyxa
Coccomyxa is a genus of green algae, in the family Coccomyxaceae. This genus is defined by their small, elliptical to spherical shape, and the presence of a simple parietal chloroplast. These features, along with their occurrence in various lifestyles such as free-living, parasitic, or as photobionts, have been used to identify over 40 species. Using additional morphological features, such as brown akinetes formation, allows for the differentiation between "Coccomyxa" and the genus "Pseudococcomyxa", as they tend to share some morphological characteristics like the general cell shape and one-sided mucilage cap. Recent molecular analysis, however, indicates that the  genus "Pseudococcomyxa" is contained within different "Coccomyxa" clades, signaling the fact that the two genera are the same. "Coccomyxa" has often been used as a model organism, and its genome is being completely sequenced. The genus is also an attractive candidate for biofuels. Etymology. "Coccomyxa" is a combination of two greco-Latin roots, cocco- and -myxa. Cocco- is a Latinized form of the Greek word "kokkos", meaning “berry”, or “seed”. This is in regards to shape, referencing that the "Coccomyxa" takes on an elliptical and globular structure. -myxa is a Greek term meaning “mucus”, in reference to "Coccomyxa"’s production  of mucoid substances. Morphology. "Coccomyxa" species are relatively small in size, measuring at about 6-14 by 3-6 μm and green in colour due to the presence of chlorophyll a and b. These green algae are elliptical to globular. Their cell wall varies in thickness, from about 40-100 nm, and the cup-shaped chloroplast makes up about half of the volume of the cell. Starch grains are located around the thylakoids. The genus "Coccomyxa" has a simple parietal chloroplast, but lacks a pyrenoid and flagellated stages. "Coccomyxa" are haplontic, meaning they spend a majority of their life cycles  as haploids, and generally reproduce asexually. Habitat and ecology. "Coccomyxa" has a worldwide distribution, and are able to form biofilms, inhabiting both marine and freshwater environments. They can be dominant in certain ecosystems and display an impressive diversity in habitat, possessing lifestyles that range from free-living to parasitic. "Coccomyxa" has been recorded free-living in terrestrial biofilms, as soil algae, connected with mosses, planktonic in limnic ecosystems, in symbiotic associations with fungi and higher plants, and parasitic to marine mussels. There is, however, no current studies that show "Coccomyxa" free-living in marine environments. Green algae have been shown  to play a significant role in ecosystems. A species of "Coccomyxa", "Coccomyxa parasitica", has been noted as parasitizing the wild mussels from the Vigo estuary in Galicia, Spain. The aggregations of the green algae occur in the mantle, gill filaments, adductor muscle, visceral mass, and haemolymph of the species "M. galloprovincialis". It also has a symbiotic relationship with fungi, specifically ascomycetes and basidiomycetes. Practical importance. "Coccomyxa" is often used as a model organism, as its entire genome sequence has been published. This allows for further research as "Coccomyxa" can serve as a frame of reference or for further experimentation. Additionally , a free living "Coccomyxa" species, "Coccomyxa" sp.C-169, was suggested to be used for biofuels, as their enzyme-digestable cell wall and lipid production gained traction for research use above other strains.