The Desmidiaceae are one of four

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

charophyte Charophyta () is a paraphyletic group of freshwater green algae, called charophytes (), sometimes treated as a division, yet also as a superdivision. The terrestrial plants, the Embryophyta emerged deep within Charophyta, possibly from terres ...

green

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

in the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Desmidiales Desmidiales, commonly called the desmids (''Gr.'' ''desmos'', bond or chain), are an order in the Charophyta, a division of green algae in which the land plants ( Embryophyta) emerged. Desmids consist of single-celled (sometimes filamentous or ...

(desmids).See the

NCBI The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is loca ...

br>webpage on Desmidiaceae
Data extracted from the Desmids in the family Desmidiaceae consist of single-celled (sometimes filamentous or colonial), microscopic green algae. Because they are highly symmetrical, attractive, and come in a diversity of forms, they are popular subjects for microscopists, both amateur and professional. Within the desmids (Desmidiales), Desmidiaceae contains tens of genera and thousands of species, making it by far the largest family. Desmidiaceae includes some of the largest and most complex desmid genera, such as ''

Micrasterias ''Micrasterias'' is a Cell (biology), unicellular green alga of the order Desmidiales. Its species vary in size reaching up to hundreds of microns. ''Micrasterias'' displays a bilateral symmetry, with two mirror image semi-cells joined by a narr ...

'', ''

Cosmarium ''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. The name ''Cosmarium'' co ...

'', ''

Staurastrum ''Staurastrum'' 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. The name ''Staurastrum'' ...

'', and ''

Euastrum ''Euastrum'' is a genus of green algae of the Desmidiaceae family.See the National Center for Biotechnology Information, NCBIbr>webpage on Euastrum Data extracted from the It lives in acidic waters. Description It is made of two, symmetrical ...

''.

Description

Desmids are single-celled (sometimes filamentous or colonial) algae, which are generally constricted in the middle, having two identical halves called semicells. The cell wall also consists of two halves. In apical view, the cells may be compressed (biradiate), three- or multi-angular (tri- or multiradiate), or circular (omniradiate). The

cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...

is marked by having pores which penetrate all cell wall layers and contain a

mucilaginous 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 ...

plug (called the pore fields). In addition to having pores, the cell wall may be covered in spines, pits ("scrobicles" or "scrobiculae"), lobes, or granules.

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 ...

s are axial or parietal.

Genera

Within the family Desmidiaceae, genera are delimited based on morphological characters such as the symmetry of the cells; whether the cells are solitary, filamentous, or colonial; the presence or absence of long processes or extensions; and the shape of the chloroplasts. However, most of these characters are highly homoplasious; therefore, many or even most genera are artificial and para- or

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 ...

. Genera accepted by

AlgaeBase AlgaeBase is a global species database of information on all groups of algae, both seaweed, marine and freshwater algae, freshwater, as well as sea-grass. History AlgaeBase began in March 1996, founded by Michael D. Guiry, Michael Guiry. Text ...

were: *'' Actinodontum'' – 3 species *''

Actinotaenium ''Actinotaenium'' is a genus of green algae, specifically of the Desmidiaceae. It is a freshwater genus, typically found in the benthos of acidic, oligotrophic lakes or ''Sphagnum'' bogs. It has a cosmopolitan distribution. ''Actinotaenium'' cons ...

'' – 66 species *'' Allorgeia'' – 2 species *'' Amscottia'' – 2 species *''

Bambusina ''Bambusina'' is a genus of freshwater green algae in the family Desmidiaceae. ''Bambusina'' is a cosmopolitan genus, typically associated with Acid, acidic and oligotrophic waters. Species of this genus, particularly ''B. borreri'', have been r ...

'' – 8 species *'' Bourellyodesmus'' – 10 species *'' Brachytheca'' – 2 species *†'' Closterimopsis'' – 1 species *''

'' – 1206 species *''

Cosmocladium ''Cosmocladium'' is a genus of freshwater green algae, specifically of the Desmidiaceae. Currently there are 7 accepted species, though there are 11 described. The holotype is '' Cosmocladium pulchellum'' Brébisson described in 1856. ''Cosmoclad ...

'' – 8 species *'' Croasdalea'' – 1 species *'' Cruciangulum'' – 1 species *''

Desmidium ''Desmidium'' is a genus of green algae,See the NCBIbr>webpage on Desmidium Data extracted from the the type genus of the family Desmidiaceae. It has a cosmopolitan distribution in acidic, oligotrophic freshwater lakes and bogs. The genus name ...

'' – 25 species *†'' Desmidopsis'' – 1 species *'' Docidium'' – 22 species *'' Euastridium'' – 3 species *''

'' – 358 species *'' Groenbladia'' – 6 species *'' Haplotaenium'' – 4 species *'' Heimansia'' – 2 species *'' Hyalotheca'' – 14 species *'' Ichthyocercus'' – 6 species *'' Ichthyodontum'' – 1 species *'' Mateola'' – 1 species *''

'' – 100 species *'' Onychonema'' – 1 species *'' Oocardium'' – 3 species *'' Pachyphorium'' – 1 species *'' Phymatodocis'' – 3 species *'' Pleurotaeniopsis'' – 1 species *'' Pleurotaenium'' – 89 species *'' Prescottiella'' – 1 species *'' Pseudomicrasterias'' – 2 species *'' Sphaerozosma'' – 20 species *'' Spinocosmarium'' – 2 species *'' Spondylosium'' – 33 species *''

'' – 788 species *'' Staurodesmus'' – 87 species *'' Streptonema'' – 3 species *'' Teilingia'' – 9 species *'' Tetmemorus'' – 10 species *'' Triplastrum'' – 3 species *'' Triploceras'' – 3 species *'' Vincularia'' – 1 species *'' Xanthidium'' – 128 species

References

Zygnematophyceae families {{green algae-stub