The Phragmoplastophyta (Lecointre & Guyader 2006) are a proposed sister clade of the
Klebsormidiaceae
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 place ...
in the
Streptophyte
Streptophyta (), informally the streptophytes (, from the Greek ''strepto'' 'twisted', for the morphology of the sperm of some members), is a clade of plants. The composition of the clade varies considerably between authors, but the definition ...
/
Charophyte
Charophyta () is a group of freshwater green algae, called charophytes (), sometimes treated as a phylum, division, yet also as a superdivision or an unranked clade. The terrestrial plants, the Embryophyta emerged within Charophyta, possibly fro ...
clade.
The Phragmoplastophyta consist of the
Charophycaea and another unnamed clade which contains the
Coleochaetophyceae
Coleochaetophyceae are a class of charophyte algae that includes some of the closest multicellular relatives of land plants
The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embr ...
,
Zygnematophyceae
Zygnematophyceae (or Conjugatophyceae) is a class of green algae in the paraphylum streptophyte algae, also referred to as Charophyta, consisting of more than 4000 described species. It contains five orders: the Spirogloeales, the Serritaeniales, ...
,
Mesotaeniaceae
The Mesotaeniaceae are a small family of unicellular green algae known as the "saccoderm desmids". The Mesotaeniaceae appear to be sister or ancestral to the Zygnemataceae. The desmids are a deep branching group of Zygnemataceae. ''Spirotaenia' ...
, and
Embryophytes
The Embryophyta (), or land plants, are the most familiar group of green plants that comprise vegetation on Earth. Embryophytes () have a common ancestor with green algae, having emerged within the Phragmoplastophyta clade of green algae as sist ...
(land plants). It is an important step in the emergence of land plants within the green algae. It is equivalent to the ZCC clade/grade,
cladistically
Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived chara ...
granting the Embryophyta.
The
mitosis
In cell biology, mitosis () is a part of the cell cycle in which replicated chromosomes are separated into two new nuclei. Cell division by mitosis gives rise to genetically identical cells in which the total number of chromosomes is mainta ...
of Phragmoplastophyta takes place via a
phragmoplast
image:Phragmoplast.png, 300px, Phragmoplast and cell plate formation in a plant cell during cytokinesis. Left side: Phragmoplast forms and cell plate starts to assemble in the center of the cell. Towards the right: Phragmoplast enlarges in a donut- ...
.
Another
synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...
of this clade is the synthesis of cellulose microfibrils by a complex of octameric cellulose synthetases. This complex crosses the plasma membrane and polymerizes molecules from the cytoplasm into cellulose microfibrils, which, together with each other, form fibrils, necessary in the formation of the wall. The Phragmoplastophyte wall is also formed of phenolic compounds.
Below is a consensus reconstruction of green algal relationships, mainly based on molecular data.
References
{{Taxonbar, from=Q3381654
Green algae