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Pseudoscytonema

Generic name: PSEUDOSCYTONEMA Elenkin, 1949. Monogr. Algarum Cyanophyc., Pars Spec. 2: 1805.
Synonyms:
Diagnosis:
Type species: Pseudoscytonema malayense (Biswas) Elenkin 1949. - Six species.
Descriptions:
Komárek (1992): Filaments rarely solitary, mainly in clusters or fine mats, isopolar, composed from a trichome with both widened ends and from a simple, firm, colourless, thin sheath, opened at the apex. Trichomes z long, uniserial, curved or flexuous, isopolar, composed from cylindrical or slightly barrel-shaped cells, which are usually longer than wide, unconstricted or constricted at the cross walls; they are shorter and wider towards the ends and the constrictions become deeper, the end cell is widely rounded or almost spherical; trichomes clearly widened at both ends. False branching rare up to common, one or two lateral branches develop after the trichome division between two vegetative cells (necridic cells ?). Cells without aerotopes, but often with solitary granules or granules near the cross walls, often vacuolized at the ends; end cells contain usually one large vacuole. Heterocytes and akinetes lacking.
Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Komárek (1992): The cell division crosswise, the daughter cells grow into original size before the next division. Reproduction by hormogonia,
liberating from the ends of trichomes; hormogonia of different length (up to 16-celled), but also short. Probably also reproduction by solitary cells
(planocytes or monocytes ?).
Ultrastructure:
Taxonomic position, higher hierarchy:
Cyanophyceae, Oscillatoriales, Ammatoideaceae
Notes to taxonomy, misinterpretations:
Ecology, ecophysiology, ecological significance:
Komárek (1992): The type species was described from the "dirty pond" in Malaysia, 4 species are known from pools, wet rocks and waterfalls in high mountains (Alps, Carpathians, Himalaya), 1 species was isolated from soils in Aroentine.
Physiology and biochemistry:
Distribution, endemism, problematic citations:
Reference strain:
Infrageneric scheme, species concept:

List of species:
Pseudoscytonema capitatum (Jaag) Anagnostidis et Komárek 1988
Pseudoscytonema congregationis (Schwabe) Anagnostidis et Komárek 1988
Pseudoscytonema endolithicum (Ercegović) Anagnostidis 2001
Pseudoscytonema malayense (Biswas) Elenkin 1949
Pseudoscytonema sphaerocephalum (Jao et Lee) Anagnostidis et Komárek 1988
Pseudoscytonema spongiosum (Schwabe) Anagnostidis et Komárek 1988
Pseudoscytonema subclavatum (Starmach) Anagnostidis et Komárek 1988

Unclear taxa:
 Plectonema algeriense Behre 1953
Plectonema corynoideum Beljakova 1989
Plectonema carneum (Kützing) Lemmermann ex Schwabe 1960 (forma "TS")

Keys:
List of stains:
Drawings:
Komárek 1992
Application technology:
Literature:

  2.1 taxonomy: Anagnostidis & Komárek 1987, Komárek 1992
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: