Scytonema

Generic name: SCYTONEMA Agardh ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 85.
Synonyms: DILLWYNELLA Bory de Saint Vincent, 1891. Dict. class. 1: 593., DIPLOCOLON Nägeli ex Bornet et Flahault, 1886. Ann. Sci. Nat.-Bot. 7, 5: 129., DRILOSIPHON Kützing, 1843. Phycol. gener., p. 214., GLOEOCHLAMYS Schmidle, 1899. Allg. Bot. Ztschr. 5: 192., INCONIA Libert, 1826. Ann. Soc. Linn. Paris 5: 402.,
SYMPHYOSIPHON Kützing, 1843. Phycol. gener., p. 218. [ SCYTONEMA Agardh, Systema Algarum, p. 26, 1824 ex Bornet et Flahault, 1886 : Conferva, Inconia, Calothrix,
Petalonema, Lyngbya, Drilosiphon, Symphyosiphon, Arthrosiphon, Spermosira, Hypheothrix, Symploca, Schizosiphon, Leptothrix, Tolipothrix, Mastigonema, Chrysostigma spec.
Diagnosis:
Bornet & Flahault (1886): Fila pseudo-ramosa; pseudo-rami solitarii vel gemini ex eruptione laterali trichomatis formati, in intervallo heterocystarum, interdum quoque, sed rarius, sub ipsis heterocystis egredientes. Trichomata in vagina solitaria, recta. Hormogonia terminalia solitaria. Sporae, in paucis speciebus tantum visae, sphaericae aut ovatae, exosporio tenui et laevi. (Conf. Borzi, loc. cit., 1879, p. 368.)
Diagnosis of Diplocolon Nägeli: Bornet et Flahault (1887): Fila pseudo-ramosa; pseudo-rami solitarii vel gemini ex eruptione laterali trichomatis formati, in intervallum hetero- cystarum, interdum quoque, sed rarius, sub heterocystis ipsi egredientes. Trichomata in vagina communi pluria, contorta Thallus difformis, constrictus, irregulariter claviformis. Terrestris.
Type species: Scytonema hofmannii Agardh ex Bornet et Flahault 1887.
Descriptions:
Komárek (1992): Filamentous - thallous; solitary branched filaments or mats on the substrate. Filaments free or in fascicles, sometimes densely coiled, creeping on the substrate or with erected branches, commonly falsely branched, with one or (obligatory) two lateral branches. Branching initiates after trichome disintegration by help of necridic cells between two heterocytes, usually not at heterocytes; both branches grow parallely aside or in crossing position; the filaments make
sometimes typical loop-like lateral formations before branching, in which tops of the trichomes later divide. Trichomes isopolar, cylindrical, not diversified in basal and apical parts,uniseriate, usually with solitary heterocytes, constricted (rarely not constricted) at cross walls; terminal parts of branches cylindrical or slightly widened, with rounded apical cell; middle parts of trichomes sometimes with elongated, cylindrical cells. Sheaths firm, limited, parallel or diverging, lamellated, usually yellow-brown (coloured by scytonemin)
in some parts. Cells pale or olive-green, usually with solitary, irregularly disposed granules or with granular content, rarely yellowish or pinkish coloured; apical cells sometimes with large vacuoles. Heterocytes intercalar, solitary, rarely in pairs, cylindrical or barrel-shaped. Akinetes were several times mentioned, but not proved and well described.
Genotype differences, molecular data:
Reproduction strategies, life cycles, cell division:
Komárek (1992): Cells divide crosswise to the trichome axis, mainly in meristematic zones near the ends of branches. Reproduction by hormogonia, which develop at the ends of branches and liberate from sheaths. Hormogonia germinate at both ends and form isopolar filaments.
Ultrastructure:
Taxonomic position, higher hierarchy: Cyanophyceae, Nostocales, Scytonemataceae
Notes to taxonomy, misinterpretations:
Ecology, ecophysiology, ecological significance:
Komárek (1992): Many Scytonema-species grow aerophytic or subaerophytic on wet rocks, wood, soil, epiphytic on mosses; several species are incrusted by calcium carbonate and represent dominant members of microphytes in travertine springs. Few species are known from atmophytic habitats near thermal waters. The submersely living species grow usually in rocky littoral of lakes, rarely among water plants, mainly on alkalic substrate, rarely in moors or acidic waters, few species are marine, occurring
on corral reefs or in brackish water. The genus is very common mainly in tropical regions, but particularly the variability of tropical taxa is unsufficiently known and many species are arbitrarily misinterpreted.
Physiology and biochemistry:
Distribution, endemism, problematic citations:
Reference strain:
Infrageneric scheme, species concept:

List of species:
Subgenus Scytonema
Scytonema aethiopicum
Scytonema ambiguum
Kützing ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 100
Scytonema arcangelii Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 92
Scytonema austinii Wood 1874
Scytonema azureum Tilden 1910
Scytonema bohnerii Schmidle 1902
Scytonema calcicola Kufferath 1914
Scytonema capitatum Gardner 1927
Scytonema chengii Wang 1934
Scytonema chiastum Geitler 1925
Scytonema cincinnatum (Kützing) Thuret ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 89
Scytonema cineraceum C.L. Zhou et H.X. Xiao 2006. Bulletin of Botanical Research 26(4): ---
Scytonema coactile (Montagne in Kützing) ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 90
Scytonema conchophilum Humphrey in Collins 1901
Scytonema concinnum Y.M. Lin et H.X. Xiao 2005. Journal of Wuhan Botanical Research 23(5): 438

Scytonema consociatum Jao 1944
Scytonema cookei W. West 1892
Scytonema crispum (Agardh) Bornet 1899
Scytonema drilosiphon (Kützing) Elenkin et Poljanskij 1922
Scytonema endolithicum Ercegović
Scytonema flavo-viride Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 101
Scytonema foliicola DeWildeman 1897
Scytonema fritschii Ghose 1924
Scytonema gomontii Gutwinski 1901
Scytonema guyanense (Montagne) Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 94
Scytonema hofmannii Agardh ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 97
Scytonema holstii Hieronymus in Engler 1895
Scytonema hyalinum Gardner 1927
Scytonema insigne W. et G.S. West 1897
Scytonema insulare Sant´Anna 1988. Nova Hedwigia 46(3-4): 528

Scytonema intertextum (Kützing) Rabenhorst 1865
Scytonema javanicum (Kützing) Bornet et Thuret ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 95
Scytonema kwangsiense Jao 1944
Scytonema lyngbyoides Gardner 1927
Scytonema malaviyanense Bharadwaya 1930
Scytonema masonianum Welsh 1963
Scytonema millei Bornet ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 93
Scytonema obscurum (Kützing) Borzì ex Forti 1907
Scytonema occidentale Setchell 1899
Scytonema ocellatum (Dillwyn) Lyngbye ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 95
Scytonema polycystum Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 90
Scytonema pseudohofmannii Bharadwaya 1934
Scytonema pseudopunctaum Skuja 1949
Scytonema punctatum Gardner 1927
Scytonema racovitzae DeWildeman
Scytonema rivulare Borzì ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 91
Scytonema rugulosum
Scytonema saleyriense Weber van Bosse 1913
Scytonema samoense Wille 1913
Scytonema schmidtii Gomont 1901
Scytonema seagriefianum Welsh 1965
Scytonema siculum Borzì ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 96
Scytonema simplex Bharadwaya 1934
Scytonema sinense Jao 1939
Scytonema stuposum (Kützing) Bornet ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 92
Scytonema subcoactile Jao 1939
Scytonema tenellum Gardner 1927
Scytonema tolypotrichoides Kützing sensu Frémy 1927
Scytonema twymanianum Welsh 1966
Scytonema varium Kützing ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 97
Scytonema verucosum
Scytonema zellerianum
Brühl et Biswass 1923


Subgenus Myochrotes (sub. sect. Myochrotes Bornet et Flahault 1882)
Scytonema amplum W. et G.S. West 1895
Scytonema bewsii Fritsch et Rich 1924
Scytonema bivaginatum Welsh 1965
Scytonema bruneum Schmidle in Simmer 1901
Scytonema burmanicum Skuja 1949
Scytonema caldarium Setchell 1899
Scytonema dilatatum
Bharadwaya1934
Scytonema fremyi Desikachary 1959
Scytonema incrassatum Jao 1944
Scytonema induratum Copeland 1936
Scytonema iyengari Bharadwaya 1934
Scytonema junipericola Farlow 1900
Scytonema leptobasis 1931
Scytonema longiarticulatum Gardner 1927
Scytonema magnum Gardner 1927
Scytonema mirabile (Dillwyn) Bornet 1889

Scytonema myochrous (Dillwyn) C.A. Agardh ex Bornet et Flahault 1887. Ann. Sci. Nat. Bot., ser. 7, 5: 104
Scytonema multiramosum Gardner 1927
Scytonema orientale Jao 1944
Scytonema pascherii Bharadwaya 1934
Scytonema planum
Scytonema pratii Komárek 1956
Scytonema pseudoguyanense Bharadwaya 1934
Scytonema pulchellum Gardner 1927
Scytonema simplex  Bharadwaya 1934
Scytonema spirulinoides Gardner 1927
Scytonema subgelatinosum Gardner 1927
Scytonema subtile Moebius 1892
Scytonema tenue Gardner 1927
Scytonema tenuissimum Frémy 1942
Scytonema tolypothrichoides (Kützing ex Bornet et Flahault 1882) ex Kosinskaja 1926

Scytonema variabile Gardner 1927

Unclear taxa:
Scytonema cuatrecasasii Gonzalez-Guerrero 1930
Scytonema minus (Schmidle) Lemmermann 1907
Scytonema sp. sensu Fritsch et Rich 1937
Scytonema  sp. sensu Nygaard 1926
Tolypothrix alata Zhou et al 2004


Synonyms
Diplocolon heppii Nägeli ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 129 = Scytonema


Excludenda

Scytonema alatum Borzi ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 110 = Petalonema
Scytonema crassum Nägeli in Kützing ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 109 = Petalonema
Scytonema crustaceum Agarh ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 106 = Petalonema
Scytonema densum Bornet in Bornet et Thuret ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 109 = Petalonema
Scytonema involvens Rabenhorst ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 108 = Petalonema
Scytonema velutinum Rabenhorst ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 5: 108 = Petalonema

Keys:
List of stains:
Drawings:
Komárek 1992
Application technology:
Literature:
  2.1 taxonomy: Geitler 1932, Geitler 1942, Jao 1944, Desikachary 1959, Hoffmann 1986a, Hoffmann 1986b, Sant' Anna 1988, Watanabe & Komárek 1988, Komárek & Anagnostidis 1989, Komárek 1992
  2.2 cytomorphology:
  2.3 16S rRNA sequencing:
  2.4 biology and life cycles:
  2.5 ecology: