explain affinities of chlorophyta with charophyta
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The Charophyta (/kæˈrɒfɪtə, ˈkæroʊfaɪtə/) or charophytes (/ˈkærəfaɪts/) is a group of freshwater green algae, sometimes treated as a division,[1] but also as a superdivision,[2] or an unranked clade. The terrestrial plants, the Embryophyta most likely emerged within Charophyta, possibly from terrestrial unicellular charophytes,[3] with the class Zygnematophyceae as a sister group.[4][5][6][7]
The clade Streptophyta is formed by the grouping together of the Embryophyta and the Charophyta.[8][9][10] 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.[11] Fossil stoneworts of early Devonian age that are similar to those of the present day have been described from the Rhynie chert of Scotland.[12]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.