| Coleochaetophyceae | |
|---|---|
 | |
| Coleochaete sp. | |
Scientific classification  | |
| (unranked): | Viridiplantae |
| (unranked): | Charophyta |
| Class: | Coleochaetophyceae C.Jeffrey [1] |
| Orders | |
Coleochaetophyceae are a class of charophyte algae that includes some of the closest multicellular relatives of land plants. Their mitogenome is the most intron rich organelle among the streptophyte algae. [2]
The Chlorophyceae are one of the classes of green algae, distinguished mainly on the basis of ultrastructural morphology. They are usually green due to the dominance of pigments chlorophyll a and chlorophyll b. The chloroplast may be discoid, plate-like, reticulate, cup-shaped, spiral or ribbon shaped in different species. Most of the members have one or more storage bodies called pyrenoids located in the chloroplast. Pyrenoids contain protein besides starch. Some green algae may store food in the form of oil droplets. They usually have a cell wall made up of an inner layer of cellulose and outer layer of pectose.
Chlorophyta or Prasinophyta is a taxon of green algae informally called chlorophytes. The name is used in two very different senses, so care is needed to determine the use by a particular author. In older classification systems, it refers to a highly paraphyletic group of all the green algae within the green plants (Viridiplantae) and thus includes about 7,000 species of mostly aquatic photosynthetic eukaryotic organisms. In newer classifications, it refers to the sister clade of the streptophytes/charophytes. The clade Streptophyta consists of the Charophyta in which the Embryophyta emerged. In this latter sense the Chlorophyta includes only about 4,300 species. About 90% of all known species live in freshwater. Like the land plants, green algae contain chlorophyll a and chlorophyll b and store food as starch in their plastids.
The Prorocentrales are a small order of dinoflagellates. They are distinguished by having their two flagella inserted apically, rather than ventrally as in other groups. One flagellum extends forward and the other circles its base, and there are no flagellar grooves. This arrangement is called desmokont, in contrast to the dinokont arrangement found in other groups. Accordingly, the Prorocentrales may be called desmoflagellates, and in some classifications were treated as a separate class Desmophyceae.
The glaucophytes, also known as glaucocystophytes or glaucocystids, are a small group of freshwater unicellular algae, less common today than they were during the Proterozoic. The stated number of species in the group varies from about 14 to 26. Together with the red algae (Rhodophyta) and the green algae plus land plants, they form the Archaeplastida. However, the relationships among the red algae, green algae and glaucophytes are unclear, in large part due to limited study of the glaucophytes.
Streptophyta, informally the streptophytes, is a clade of plants. The composition of the clade varies considerably between authors, but the definition employed here includes land plants and all green algae except the Chlorophyta and possibly the more basal Mesostigmatophyceae, Chlorokybophyceae, and Spirotaenia.
The Charophyta or charophytes is a group of freshwater green algae, sometimes treated as a division, but also as a superdivision, or an unranked clade. The terrestrial plants, the Embryophyta emerged within Charophyta, possibly from terrestrial unicellular charophytes, with the class Zygnematophyceae as a sister group.
AlgaeBase is a global species database of information on all groups of algae, as well as one group of flowering plants, the sea-grasses.
Nephroselmis is a genus of green algae. It has been placed in the family Nephroselmidaceae, although a 2009 study suggests that it should be separated into its own class, Nephroselmidophyceae. One species can be an endosymbiont of Hatena arenicola.
Chlorokybus is a multicellular (sarcinoid) genus of basal green algae or charophyte, a soil alga. It has been classified as the sole member of the family Chlorokybaceae, which is the sole member of the order Chlorokybales, in turn the sole member of the class Chlorokybophyceae.
Mesostigma is a genus of freshwater green algae, with a single species Mesostigma viride. As of February 2022, AlgaeBase classified it as the only genus in the family Mesostigmataceae, the only family in the order Mesostigmatales, the only order in the class Mesostigmatophyceae. It is now considered to be one of the earliest diverging members of green plants/algae (Viridiplantae).
Zygnematophyceae is a class of green algae in the division Charophyta, consisting of more than 4000 described species. It contains the order Zygnematales. The Desmidiales emerged within the Zygnematales. The Zygnematophyceae are the sister clade of the Mesotaenium, together forming the sister clade of the land plants. The body plan of Zygnematophyceae is simple, and appear to have gone through a secondary loss of morphological complexity. They contain genes involved in protection from desiccation that appear to have been derived by horizontal gene transfer from bacteria; the genes are found in plants, Zygnematophyceae, bacteria, but no other organisms. The genes may have helped to enable plants to make the transition to life on land.
Coleochaetaceae is a family of algae. It is the only family in the Coleochaetales, an order of parenchymous charophyte algae, that includes some of the closest multicellular relatives of land plants. They questionably include the fossil genus Parka.
The Klebsormidiaceae are a family containing five genera of charophyte green alga forming multicellular, non-branching filaments. The genus Chlorokybus was previously included as well, but this problematic and poorly known genus is now placed in a separate class Chlorokybophyceae.
The Phragmoplastophyta are a proposed sister clade of the Klebsormidiaceae, with which they form the Streptophyte/Charophyte clade. The Phragmoplastophyta consist of the Charophycaea and another unnamed clade which contains the Coleochaetophyceae, Zygnematophyceae, Mesotaeniaceae, and Embryophytes. It is an important step in the emergence of land plants within the green algae. It is equivalent to the ZCC clade/grade, cladistically granting the Embryophyta.