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Siphononema

Generic name: SIPHONONEMA Geitler, 1925. Arch. Protistenk. 51: 332.
Synonyms:
Diagnosis:
Type species: Siphononema polonicum (Raciborski) Geitler 1925. - Two species.
Descriptions:
Komárek & Anagnostidis (1998): Thallus (colonies) polarized, attached by one end to the substrate, micro- to macroscopic. Initial cells solitary, cylindrical or subspherical to irregularly and narrowly club-shaped, attached by the basal end to the substrate, straight or slightly curved, with colourless and/or later yellowish pseudovagina, later dividing intensely in the upper part and forming pseudofliamentous to irregular, large colonies of aggregated cells; cells are oriented more or less in rows within thallus, or (in old parts) irregularly. Cells sometimes produce their individual mucilaginous, colourless envelopes, which are lamellate in old parts of thallus
and yellowish-brown or orange coloured (in one species).
Komárek (1992): Colonial; initial cells solitary, cylindrical up to irregularly and narrowly club-shaped, by the basal end attached to the substrate, straight or slightly curved, with colour less and later yellowish pseudovagina, later dividing intensely in the upper part and forming pseudofilamentous up to irregular, rich colonies of cells, which are oriented within thallus more or less in rows or (in old parts) irregularly. Thallus micro-up macroscopic. Cells produce their own mucilaginous colour less envelopes, which are in old parts of thallus lamellated and yellowish-brown or orange coloured.

Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Komárek & Anagnostidis (1998): Cells divide irregularly, usually in three or various planes in successive generations (development of «stigonematoid" thallus), but in apical parts or in sides of thallus with predominating crosswise fission (development of rows of cells). Reproduction by solitary cells or groups of cells with their own gelatinous envelopes; solitary cells (motile monocytes, planocytes) escape from the splitting envelopes at the marginal and apical parts of thallus (after which remain the cup-shaped remnants of sheaths). Resting stages (cells enveloped by firm sheaths) were also described.
Komárek (1992): Cells divide irregularly, usually in three or more planes in successive generations (development of "stigonematoid" thallus), but in apical parts of thallus or in its sides with prevailing crosswise fission (development of rows of cells). Reproduction by solitary cells or groups of cells enveloped by gelatinous envelopes or by solitary cells (motile planocytes), which escape from the splitting envelopes at the marginal and apical parts of thallus (after which remain the cup-shaped rests of sheaths). The resting stages (cells enveloped by firm sheaths) were also described.
Ultrastructure:
Taxonomic position, higher hierarchy:
Cyanophyceae, Chroococcales, Entophysalidaceae, Siphononematoideae
Notes to taxonomy, misinterpretations:
Ecology, ecophysiology, ecological significance:
Komárek (1992): The type species S. polonicum grows epilithic in the surf zone of cold and clear mountain (alpine) streams and littorals of lakes; till now known from the limestone areas of the European high mountain areas (Alps, highest part of Carpathians, etc.). Second species described from thermal springs in Czechoslovakia (western Carpathians).
Physiology and biochemistry:
Distribution, endemism, problematic citations:
Reference strain:
Infrageneric scheme, species concept:
List of species:
Siphononema polonicum (Raciborski) Geitler 1925
Siphononema thermophilum Hindák 1978
Keys:
List of stains:
Drawings:
Komárek 1992
Application technology:
Literature:

  2.1 taxonomy: Geitler 1925, Geitler 1932, Geitler 1942, Hindák 1978, Komárek 1992, Komárek & Anagnostidis
1998
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: