Superregnum: Eukaryota
Regnum: Plantae
Divisio: Chlorophyta
Subphylum: Chlorophytina
Classis: Chlorophyceae
Ordo: Chlamydomonadales
Familia: incertae sedis
Genus: Hydrianum
Species: H. coronatum – H. crassiapex – H. diogenes – H. ellipticum – H. gracile – H. lageniforme – H. ovale – H. pyrenoidiferum – H. variabile – H. viride
Name
Hydrianum Rabenhorst, 1868: 19, fig. 41, 87
Type species (Lectotype, designated in Fott 1975: 221): Hydrianum ovale Rabenhorst
Synonyms
Chlororhabdion Jane, 1944
Type Species: Chlororhabdion diogenes Jane
References
Primary references
Rabenhorst, L. 1868. Flora europaea algarum aquae dulcis et submarinae. Sectio III. Algae chlorophyllophyceas, melanophyceas et rhodophyceas complectens. pp. i–xx, 1–461, 51 figs. Lipsiae [Leipzig]: Apud Eduardum Kummerum. BHL Reference page.
Fott, B. 1975. Übersicht der Familie der Characiaceae (Chlorococcales) mit taxonomischen Namensänderungen und Neubeschreibungen. Preslia 47: 211–231. PDF Reference page.
Jane, F.W. 1944. Chlororhabdion, a new genus of the Xanthophyceae. Journal of the Royal Microscopical Society 64: 16–25. DOI: 10.1111/j.1365-2818.1944.tb06160.x Reference page.
Links
Guiry, M.D. & Guiry, G.M. 2024. Hydrianum. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Accessed 2024-03-21.
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
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
Guiry, M.D.; Guiry, G.M. "Hydrianum". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2022-02-25.
Guiry, M.D.; Guiry, G.M. "Chlororhabdion". AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Retrieved 2024-11-30.
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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