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Radaisia

Generic name: RADAISIA Sauvageau, 1895. J. Bot. 9: 374.
Synonyms:
Diagnosis:
Type species: Radaisia gomontiana Sauvageau 1895
Descriptions:
Komárek & Anagnostidis (1998): Thallus at first in the form of a flat, discoidal or irregular, nemato- or blastoparenchymatous colony (these stages rarely lacking), attached to the substrate, from which more or less erect, short, parallely arranged, straight or slightly curved, simple or sometimes pseudodichotomously divaricate, uniseriate or multiseriate rows of cells (pseudofilaments) arise. Mucilaginous sheaths around pseudofilaments confluent, forming later homogeneous mucilage; old colonies m the form of a narrow, flat, gelatinous or crustose layer with parallely arranged pseudofilaments, oriented perpendicularly to the substrate. Cells more or less irregular- polyhedral-rounded, at the ends of pseudofilaments enlarged; the apical cells, dividing later into baeocytes, are therefore larger than vegetative cells and develop terminally or subterminally, on the top of pseudofilaments, i. e., near the surface of flat colonies.
Komárek (1992): Unicellular - colonial - pseudofilamentous; thallus crust-like, composed from more or less erect, parallel situated pseudofilaments; cells situated in irregular, mono- or multilayered rows, enveloped by firm gelatinous sheaths, which confluent by their sides together. Cells more or less irregular polyhedral, at the ends of erect pseudofilaments enlarged.
Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Komárek & Anagnostidis (1998): Cells divide within thallus irregularly, in pseudofilaments predominantly crosswise in one plane in successive generations. Baeocytes differentiate by simultaneous or successive cell divisions of apical cells. Reproduction by baeocytes, many per cell, and later liberated from the colony. From about ten described species, several are satisfactorily characterized, however, only one (the type species) is known from Europe.
Komárek (1992): Cells divide within thallus irregularly, in pseudofilamentous rows predominantly in one plane in successive generations. Large apical and subapical cells often divide in great amount of nanocytes. Reproduction probably by nanocytes.
Ultrastructure:
Taxonomic position, higher hierarchy:
Cyanophyceae, Chroococcales, Hyellaceae, Hyelloideae
Notes to taxonomy, misinterpretations:
Ecology, ecophysiology, ecological significance:
Komárek (1992): Majority of species known from marine biotopes, one species described from streams in central Africa. All species need taxonomic revision; they are very little known, not found again after their description.
Physiology and biochemistry:
Distribution, endemism, problematic citations:
Reference strain:
Infrageneric scheme, species concept:
List of species:
Radaisia clavata Setchel et Gardner in Gardner 1918
Radaisia confluens Gardner 1927
Radaisia epiphytica Setchel et Gardner in Gardner 1918
Radaisia gardneri Komárek et Anagnostidis 1995
Radaisia gomontiana Sauvageau 1895
Radaisia pusilla Weber van Bosse 1926
Radaisia willei Gardner 1927

Unclear taxa:
Pleurocapsa entophysaloides Setchel et Gardner in Gardner 1918
Pleurocapsa subgelatinosa Geitler 1933

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

  2.1 taxonomy: Sauvageau 1895, Gardner 1918, Setchell & Gardner 1919, Gardner 1927, Geitler 1932, Frémy 1934, Geitler 1942, Bourrel1y 1977, Komárek 1992, Komárek & Anagnostidis 1998
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: