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Hydrianum

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Hydrianum
Hydrianum ovale
Scientific classification Edit this classification
Clade: Viridiplantae
Division: Chlorophyta
Class: Chlorophyceae
Order: Chlamydomonadales
Family: incertae sedis
Genus: Hydrianum
Rabenhorst, 1868
Type species
Hydrianum ovale
Rabenhorst[1]
Species[1]
Synonyms
  • Chlororhabdion F.W.Jane[2]

Hydrianum is a genus of green algae, in the order Chlamydomonadales. It is found in freshwater habitats such as marshes and bogs, as an epiphyte on plants or other algae.[1] It is common, but most likely overlooked due to its similarity with similar genera such as Characium.[3]

Description

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Hydrianum consists of solitary or clustered cells attached to a substrate, via a mucilaginous pad or a stipe. Cells are cylindrical, oval, or spindle-shaped; in some species they are distinctly curved. Cells are uninucleate (with a single nucleus), they contain a single parietal chloroplast (or multiple when older). Pyrenoids are generally absent but may be present in a few species.[1]

Asexual reproduction occurs via the formation of zoospores; the zoospores are released through a rupture near the apex of the cell wall, while one zoospore stays behind and develops into a new vegetative cell. Zoospores have two flagella and a single chloroplast. After swimming, the zoospores settle and develop into a new cell. Sexual reproduction has not been observed in this genus.[1]

Members of Hydrianum with a pyrenoid can be confused with Characium, but in Hydrianum the zoospores exit subapically or apically, while in Characium the zoospores exit through a lateral opening. Additionally, in Hydrianum a zoospore may remain in the sporangium and develop into a new cell. The genus is also similar to Characiopsis, which generally lacks pyrenoids, but is unrelated.[3]

References

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  1. ^ a b c d e Guiry, M.D.; Guiry, G.M. "Hydrianum". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2022-02-25.
  2. ^ Guiry, M.D.; Guiry, G.M. "Chlororhabdion". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2024-11-30.
  3. ^ a b Komárek, J.; Fott, B. (1983). Chlorophyceae (Grünalgen), Ordnung Chlorococcales. Das Phytoplankton des Süßwassers (in German). E. Schweizerbart'sche Verlagsbuchhandlung. p. 1044.
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