''Radiofilum'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

green algae The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ...

in the class

Chlorophyceae The Chlorophyceae, also known as chlorophycean algae, are one of the classes of green algae, within the phylum Chlorophyta. They are a large assemblage of mostly freshwater and terrestrial organisms; many members are important primary producers i ...

. It is a

freshwater Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mi ...

genus; they are often found in soft, boggy or acidic waters. ''Radiofilum'' consists of unbranched filaments of cells, surrounded by a very thin

mucilage Mucilage is a thick gluey substance produced by nearly all plants and some microorganisms. These microorganisms include protists which use it for their locomotion, with the direction of their movement always opposite to that of the secretion of ...

layer. Cells are bead-like, spherical or compressed. The cell wall consists of two halves, and there is a ring around the middle of the cell where the two halves are joined. Cells contain a

chloroplast A chloroplast () is a type of membrane-bound organelle, organelle known as a plastid that conducts photosynthesis mostly in plant cell, plant and algae, algal cells. Chloroplasts have a high concentration of chlorophyll pigments which captur ...

is parietal and contains one or more

pyrenoid Pyrenoids are sub-cellular phase-separated micro-compartments found in chloroplasts of many algae,Giordano, M., Beardall, J., & Raven, J. A. (2005). CO2 concentrating mechanisms in algae: mechanisms, environmental modulation, and evolution. ''An ...

s. The genus ''Radiofilum'' as currently

circumscribed In geometry, a circumscribed circle for a set of points is a circle passing through each of them. Such a circle is said to ''circumscribe'' the points or a polygon formed from them; such a polygon is said to be ''inscribed'' in the circle. * Circum ...

appears to be a polyphyletic grouping of species. Some work has been done to transfer species to other genera, including '' Interfilum'' and '' Flintia''. The type species, '' Radiofilum conjunctivum'', belongs to the class

Trebouxiophyceae The Trebouxiophyceae, also known as trebouxiophytes, are a class of green algae, in the division Chlorophyta. Members of this class are single-celled, colonial, or multicellular and are found in freshwater, terrestrial or marine habitats worldwid ...

and is phylogenetically close to the genus ''

Microthamnion ''Microthamnion'' is a genus of green algae in the family Microthamniaceae. It is found in freshwater habitats around the world, preferably with low levels of pollution; it is typically attached to solid substrates. Description ''Microthamnion' ...

''.

References

Sphaeropleales genera Sphaeropleales Freshwater algae {{Chlorophyceae-stub