Streptophyta in the context of Plant


Streptophyta in the context of Plant

⭐ Core Definition: Streptophyta

Streptophyta (/strɛpˈtɒfɪtə, ˈstrɛptftə/), informally the streptophytes (/ˈstrɛptəfts/, 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 employed here includes land plants and all green algae except the Chlorophyta and the more basal Prasinodermophyta.

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Streptophyta in the context of Green algae

The green algae (sg.: green alga) are a group of chlorophyll-containing autotrophic algae consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/Streptophyta. The land plants (Embryophyta) have emerged deep within the charophytes as a sister of the Zygnematophyceae. Since the realization that the Embryophyta emerged within the green algae, some authors are starting to include them. The completed clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae and as the kingdom Plantae. The green algae include unicellular and colonial flagellates, most with two flagella per cell, as well as various colonial, coccoid (spherical), and filamentous forms, and macroscopic, multicellular seaweeds. There are about 22,000 species of green algae, many of which live most of their lives as single cells, while other species form coenobia (colonies), long filaments, or highly differentiated macroscopic seaweeds.

A few other organisms rely on green algae to conduct photosynthesis for them. The chloroplasts in dinoflagellates of the genus Lepidodinium, euglenids and chlorarachniophytes were acquired from ingested endosymbiont green algae, and in the latter retain a nucleomorph (vestigial nucleus). Green algae are also found symbiotically in the ciliate Paramecium, and in Hydra viridissima and in flatworms. Some species of green algae, particularly of genera Trebouxia of the class Trebouxiophyceae and Trentepohlia (class Ulvophyceae), can be found in symbiotic associations with fungi to form lichens. In general, the fungal species that partner in lichens cannot live on their own, while the algal species is often found living in nature without the fungus. Trentepohlia is a filamentous green alga that can live independently on humid soil, rocks or tree bark or form the photosymbiont in lichens of the family Graphidaceae. Also the macroalga Prasiola calophylla (Trebouxiophyceae) is terrestrial, andPrasiola crispa, which live in the supralittoral zone, is terrestrial and can in the Antarctic form large carpets on humid soil, especially near bird colonies.

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Streptophyta in the context of Charophyta

Charophyta (UK: /kəˈrɒfɪtə, ˌkærəˈftə/) is a paraphyletic group of freshwater green algae, called charophytes (/ˈkærəˌfts/), sometimes treated as a division, yet also as a superdivision. The terrestrial plants, the Embryophyta emerged deep within Charophyta, possibly from terrestrial unicellular charophytes, with the class Zygnematophyceae as a sister group.

With the Embryophyta now cladistically placed in the Charophyta, it is a synonym of Streptophyta. The sister group of the charophytes are the Chlorophyta. In some charophyte groups, such as the Zygnematophyceae or conjugating green algae, flagella are absent and sexual reproduction does not involve free-swimming flagellate sperm. Flagellate sperm, however, are found in stoneworts (Charales) and Coleochaetales, orders of parenchymatous charophytes that are the closest relatives of the land plants, where flagellate sperm are also present in all except the conifers and flowering plants. Fossil stoneworts of early Devonian age that are similar to those of the present day have been described from the Rhynie chert of Scotland. Somewhat different charophytes have also been collected from the Late Devonian (Famennian) Waterloo Farm lagerstätte of South Africa. These include two species each of Octochara and Hexachara, which are the oldest fossils of Charophyte axes bearing in situ oogonia.

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Streptophyta in the context of Prasinodermophyta

The marine Prasinodermophyta are a proposed basal Viridiplantae clade, as sister of another clade comprising the Chlorophyta and the Streptophyta. It consists of the Prasinodermophyceae and the Palmophyllophyceae, and is informally called prasinodermophytes. They were previously considered to be a basal Chlorophyta clade, or part of the "prasinophytes".

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Streptophyta in the context of Zygnematales

The Zygnematales (Greek: ζυγός (zygós) and νῆμα (nḗma) (nom.), νήματος (nḗmatos) (gen.)), also called the Conjugatales, are an order of green algae, comprising several thousand different species in two families. The larger family Zygnemataceae, with well-known genera such as Zygnema and Spirogyra, includes members that grow as unbranched filaments, which grow longer through normal cell division. This group includes the desmids. Most members of both families live in freshwater, and form an important component of the algal scum that grows on or near plants and rocks.

Systematically they fall within the division Charophyta/Streptophyta, in which the land plants (Embryophyta) emerged.

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Streptophyta in the context of Eu-

This is a list of common affixes used when scientifically naming species, particularly extinct species for whom only their scientific names are used, along with their derivations.

  • -ales: Pronunciation: /ˈa.lis/. Origin: Latin: -ālis. Meaning: Used to form taxonomic names of orders for plants and fungi.
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Streptophyta in the context of 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 placed in a separate class Chlorokybophyceae.

Klebsormidiaceae are the sister to the Phragmoplastophyta. Their ancestor was probably a multicellular freshwater green algae, and multicellularity will be retained in all of its descendants except the Zygnematophyceae, which reverted back to unicellularity. Together with the unicellular Chlorokybophytina (Mesostigmatophyceae, Spirotaenia and Chlorokybophyceae), they comprise the Streptophyta.

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