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Spirirestis

Generic name: SPIRIRESTRIS Flechtner et Johansen in Flechtner et al., Nova Hedwigia 74(1-2): 6 2002
Synonyms:
Diagnosis:
Flechtner et al.(2002)Colonia molliter acervata in agaro, marginibus leviter irregularibus, non caespitosa, atroveneta, remantes atroveneta ad menses quatuor; olivacea vel ochracea ad mortem cellulosum in culturis vetustioribus siccis. Colonia compacta, filis dense dispositis, non mucilagina. Fila non horizontaliter vel verticaliter extensa e colonia etsi visibiles intra coloniam. Morphologia colonialis similaris in ambobus agaro basali Boldii et agaro Z-8. Fila spiras arctas regulares formantia, 6-20 um diametro. Spirae leviter decrescentes in culturis novis, 16-28 um diametro ad partem latissimam, 12-16 um diametro ad extrema angustata spirarum, distantia inter spiras regulares 8-12(-16) um. Fila interdum in spiras laxiores contorta vel etiam extensa, haec in culturis vetustioribus frequentiora. Rami falsi duplices vel simplices, in spiras laxas vel in fila extensa praesentes, non observati in spiras arctas. Rami falsi plerumque ab heterocyteis distantes. Vagina firma plerumque incolorata, interdum succinea vel umbrina, in culturis novis tenuis, in culturis vetustioribus crassiorescens, 1-4 um lata. Trichomata ad septa haud constrictae ad leviter constrictas, in culturis vetustioribus et in filis laxiter spiralibus vel extensis frequenticus constrictae, 5.5-14.0 um diametro. Cellulae plerumque breviores quam longae, infrequenter quadratae, 2.0-7.2 um longae, sine aerotopis, contentis interdum granularibus praecipue in culturis vetustioribus. Heterocyteae intra filas intercalares vel baseless, pro parte maxima simplices, in positione intercalari infrequenter duplices, raro triplices, sphaericae ad ovales, interdum in positione basali adpressae in latere uno, brunnescentes, 8-9 um diametro, 4-9 um longae.
Typus SRS70 die 19. Maji 1995 a solo deserti, lat. bor. 39°06.066', long. occ. 110°44.713', Pro-spectus Cunei, Sanctus Raphael Unda, Utah, USA. Holotypus hic designatus: BRY C 35162, Herbarium Cryptogamorum Nonvascularium, Brigham Young University, Provo, Utah. Isotypi: BRY C 35162, Herbarium Cryptogamorum Nonvascularium, Brigham Young University, Provo, Utah. Isotypus in statu vivo: 2660, UTEX Congeries Culturamm, University of Texas.Austin, Texas.
A Scytonema et Tolypothrix filis regulatim arcte torsivis in helices dextrales differt. Fila libra, regulatim arcte torsiva. Rami falsi duplices vel simplices. Vaginae firmae, tenues vel crassae, interdum lamellatae. Trichomata solitaria intra vaginam. Cellulae breviores quam latae. Heterocyteae intercalares vel basilares, sphaericae ad ovales vel adpressae. Akineta non observata.
Type species: Spirirestris rafaelensis Flechtner et Johansen in Flechtner et al., Nova Hedwigia 74(1-2): 7 2002
Descriptions:
Flechtner et al.(2002):Colony softly mounded on agar, with slightly irregular margins, not tufted, dark blue-green, maintaining its colour at four months; the only evidence of colour change to olive or ochre occurring with cell death in drying, older cultures. Colony compact, with densely arranged filaments, but no evidence of external mucilage production. Although filaments can be seen within the colony at 30x magnification, filaments do not extend horizontally or vertically from the colony. Colony morphology is similar on both Bold's Basal and Z-8 media. Filaments forming tight, regular spirals which can be seen to taper slightly in young cultures. Filaments 6-20 um in diameter; spirals 16-28 urn in diameter at their widest point, tapered end of spirals about 75-80% of the maximum diameter; distance between regular spirals 8-12(-16) um. Some filaments more loosely coiled, or even extended; these filaments increasing in frequency in older cultures. Both single and double false branching occasionally observed in more loosely coiled or extended filaments, but not in tightly spiraled filaments. False branching usually distant from the heterocytes. Sheath firm, usually colourless, occasionally golden to brown, thin in young cultures becoming thicker and lamellated in older cultures, 1-4 um thick. Trichomes not to slightly constricted at the crosswalls, more commonly constricted in older cultures and in loosely coiled or extended filaments, 5.5-14.0 um in diameter.Cells mostly shorter than wide, occasionally quadratic, 2.0-7.2 um long, without aerotopes, cell contents sometimes granular, especially in older cultures. Heterocytes both intercalary and basal within filaments, mostly single but occasionally double in intercalary position, rarely triple, spherical to oval, sometimes appressed on one side in basal position, light brown, 8-9 um in diameter, 4-9 um long.
Differs from Scytonema and Tolypothrix in that the filaments are regularly, tightly coiled in a right-handed helix. Filaments free, forming tight, regular spirals. False branches double or single. Sheaths firm, thin to thick, sometimes lamellated. Trichomes solitary within the sheath. Cells shorter than broad. Heterocytes both intercalary and basal, spherical to oval or appressed. Akinetes not observed.
Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Ultrastructure:
Taxonomic position, higher hierarchy: Cyanophyceae, Nostocales, Scytonemataceae
Notes to taxonomy, misinterpretations:
Ecology, ecophysiology, ecological significance:
Flechtner et al.(2002): Arid soils, Utah, Texas, USA
Physiology and biochemistry:
Distribution, endemism, problematic
citations:
Reference strain:
Infrageneric scheme, species concept:
List of species:
 Spirirestris rafaelensis Flechtner et Johansen in Flechtner et al., Nova Hedwigia 74(1-2): 7 2002
Key:
List of strains:
Drawings, images:
Flechtner et al.(2002:8-10):
Application technology:
Literature:

  2.1 taxonomy: Flechtner et al. 2002
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: