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Clastidium

Generic name: CLASTIDIUM Kirchner, 1880. Jahresh. Ver. Vaterl. Naturk. Württemb. 36: 196.
Synonyms: [ Drouet & Daily, 1956; identical]
Diagnosis:
Type species: Clastidium setigerum Kirchner, 1880.
Descriptions:
Komárek & Anagnostidis (1998): Cells solitary or in groups, heteropolar, attached to the substrate by their basal ends, elongate, ovoid, ellipsoidal, pear-shaped to cylindrical, widely or narrowly rounded at their bases, more or less narrowed to the apex and extended into a fine gelatinous hair; cells with homogeneous content. Mucilaginous sheaths (pseudovagina) thin, firm, sometimes slightly and indistinctly lamellate.
Komárek (1992): Unicellular; solitary elongated cells, rarely grouped together, joined more or less perpendicularly by one (basal) end to the substrate, usually to filamentous algae or submerged water plants. Cells always polarized, attached to the substrate by the narrowed mucilaginous pad, on the apical end also narrowed and prolonged into thin mucilaginous hair-like string (sometimes long); cell-form widely oval, ellipsoidal, ovoid or pear-shaped, rarely slightly club-shaped. Around cells sometimes thin, mucilaginous, often diffluent, colourless sheaths (pseudovaginae), which open at the top during the cell division, if remained. Cell content pale blue-green, usually without visible granules, always without aerotopes.
Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Komárek & Anagnostidis (1998):Cell division by successive transverse division in the apical part or (very rarely?) along the whole length of the cell (exocyte formation). Exocytes (motile) more or less spherical or slightly elongate, separate from the apical cell end solitary or in a cluster, and attach again to the substrate. The basal remnant of the mother cell develops often into a new mother cell.
Komárek (1992):Cells divide firstly asymmetrically in their apical parts, later successively or almost spontaneously, always perpendicularly to the long axis of a cell, forming sometimes a row of daughter cells (exocytes) at the apical end, from which they liberate and join again to the substrate; sometimes remains the basal part of the cell undivided and further divisions proceed successively only in the upper part of the cell. The basal sterile part can again grow and again to divide at its apical end. Rarely divides the whole elongated cell into daughter cells - exocytes. The young cellsdevelop firstly with rounded apex, only later form the apical mucilaginous strings.
Ultrastructure:
Taxonomic position, higher hierarchy:
Cyanophyceae, Chroococcales, Chamaesiphonaceae
Notes to taxonomy, misinterpretations:Four
species
Ecology, ecophysiology, ecological significance:
Komárek (1992):All species are known from clear, streaming or stagnant mountains waters,the commonest (and probably cosmopolitan) C. setigerum grows on algae and plants, C. rivulare usually on stones in European mountain areas; C. sicyoideum is known only from Chinese mountains. One species is known from Arctic Canadian lakes.
Physiology and biochemistry:
Distribution, endemism, problematic
citations:
Reference strain:
Infrageneric scheme, species
concept:
List of species:

Clastidium cylindricum Whelden 1947
Clastidium nepalense M. Watanabe et Komárek 1998
Clastidium rivulare (Hansgirg) 1892
Clastidium setigerum Kirchner 1880
Clastidium sicyoideum Li 1984
Keys:
List of stains:
Drawings:
Komárek (1992)
Application technology:
Literature:

  2.1 taxonomy: Kirchner 1880, Geitler 1932, Geitler 1942, Starmach 1966, Golubić 1967, Geitler 1975, Geitler 1977, Economou-Amilli & Anagnostidis 1981, Hallfors & Munsterhjelm 1982, Li 1984, Komárek & Anagnostidis 1986, Komárek 1992, Komárek & Anagnostidis 1998
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: