Koliellaceae is a family of

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 order

Prasiolales Prasiolales is an order (biology), order of green algae in the Class (biology), class Trebouxiophyceae. Members of this order are ecologically widespread and are found in freshwater, marine, and terrestrial habitats from the Arctic to the Antarct ...

. Koliellaceae was circumscribed by

František Hindák František () is a masculine Czech and Slovak given name. It is a cognate In historical linguistics, cognates or lexical cognates are sets of words that have been inherited in direct descent from an etymological ancestor in a common pare ...

in 1996 to include various green algae that reproduce mainly by simple cell division. Cells are solitary or found in small colonies or filaments. Cells are cylindrical to spherical, with or without a layer of mucilage. The cell wall may be smooth or covered with granulations. Cells contain a single, parietal

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 ...

with or without a pyrenoid. Reproduction is typically by cell division into two equally sized cells; however, aplanospores or zoospores may be formed occasionally. Sexual reproduction is

oogamous Oogamy is a form of anisogamy where the gametes differ in both size and form. In oogamy the large female gamete (also known as ovum) is immotile, while the small male gamete (also known as spermatozoon) is mobile. Oogamy is a common form of anis ...

. The taxonomy of this family is problematic because

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

s have shown the type genus '' Koliella'' is

polyphyletic A polyphyletic group is an assemblage that includes organisms with mixed evolutionary origin but does not include their most recent common ancestor. The term is often applied to groups that share similar features known as Homoplasy, homoplasies ...

. The type species of ''Koliella'', '' K. spiculiformis'', forms a clade that is closely related to ''

Chlorella ''Chlorella'' is a genus of about thirteen species of single- celled or colonial green algae of the division Chlorophyta. The cells are spherical in shape, about 2 to 10 μm in diameter, and are without flagella. Their chloroplasts contain t ...

''; meanwhile, most other species of ''Koliella'' and ''Raphidonema'' are part of a clade including ''

Prasiola ''Prasiola'' is a genus of macroscopic green algae, found in a variety of habitats ranging from terrestrial, freshwater, to marine. The genus has a cosmopolitan distribution, ranging from the Arctic to the Antarctic. Plants belonging to the genu ...

'' and '' Stichococcus''. Since Hindák's circumscription, a number of genera have been added to the family Koliellaceae based on their placement in their placement in the latter clade, that differ from its original morphological definition. Examples include '' Pseudochlorella'', which consists of single, coccoid cells, and '' Ekerewekia'', which forms branched filaments of cells.

References

Trebouxiophyceae families Prasiolales {{Green algae-stub