Aphanizomenon
| Generic name: APHANIZOMENON Morren ex Bornet et Flahault 1888. Ann. Sci. Nat. Bot., ser. 7, 7: 241. | ||||||||||
| Synonyms: LIMNANTHE Kützing, 1843. Linaea: 86. LIMNOCHLIDE Kützing, 1843. Phycol. gener., p. 203. [ APHANIZOMENON Morren, Histoire d'un genre nouveau de la tribu des Confervées, nommé par l'auteur Aphanizoméne, in Mémoires de l'Acad. royale de Belgique, 1838, XI, p.11. ex Bornet et Flahault, 1886: Byssus, Conferva, Sphaerozyga, Limnanthe, Limnochlide sp.] |
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| Diagnosis: Bornet et Flahault (1888): Thallus minimus squamiformis, aerugineus, libere natans, e filis in laminulas plumosas vel in fasciculos fusiformes aggregatis formatus; trichomata evaginata, utrinque attenuata; sporae cylindricae elongatae in inlervallo heterocystarum formatae, solitariae, inter heterocystas sparsae. |
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| Type species: Aphanizomenon flos-aquae Ralfs ex Barnet et Flahault 1888. |
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| Description: Komárek (1992): Filamentous; filaments free-floating, solitary, only in few species joined into fascicle-like, microscopic or macroscopic (up to 2 cm long) colonies with parallely oriented trichomes; trichomes straight, slightly curved or slightly coiled, along the length cylindrical or sharply or continually narrowed to the ends, at cross walls not constricted or constricted, always without firm sheaths, several species with very fine, mucilaginous, diffluent and colourless envelope (?); trichomes uniserial, in the middle part usually cylindrical, isopolar, with distinctly elongated and sometimes vacuolized cells at ~ the ends, with the apical cells long, cylindrical and hyaline (at the end rounded or obtuse), or intensely elongated, narrowed, vacuolized up to hyaline and sharply or bluntly pointed, or conical, slightly elongated and only occasionally with small vacuoles (subgenera?); trichomes always subsymmetric, with 1-3 distant, intercalary developed heterocytes, which are localized subsymmetrically at the fully developed trichomes (shifted to one end of a trichome). Vegetative cells cylindrical or barrel-shaped, more or less isodiametrical or slightly shorter or longer than wide, pale blue-green or blue-green, usually with aerotopes, but several species facultatively or always without gas vesicles under special environmental conditions. Heterocytes barrel-shaped or cylindrical with rounded or obtuse ends, which can completely disappear under special conditions (under high N-content). Akinetes rarely spherical or widely oval, usually oval to long, cylindrical with rounded ends, developing raheterocytically, solitary or in short rows (in two or three), close to heterocytes or slightly,; distant from them, usually in asymmetrical position in a trichome. |
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| Genotype differences, molecular data: | ||||||||||
| Reproduction strategies, life cycles, cell division: Komárek (1992):Vegetative cells divide cross-wise and grow to the original size before the next division; terminal cells not capable to divide; without meristematic zones. Reproduction by trichome disintegration and by akinetes. |
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| Ultrastructure: | ||||||||||
| Taxonomic position, higher hierarchy: Cyanophyceae, Nostocales, Nostocaceae, Anabaenoideae Notes to taxonomy, misinterpretations: |
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| Ecology, ecophysiology, ecological significance: Komárek (1992):Almost all species are planktic, sometimes forming characteristic water blooms, the most known type species (A. flos-aquae) is important in managed fish ponds and in lakes; mainly are distributed in eutrophic water reservoirs, few species are halophilic. All species have limited areas of distribution (and possess characteristic species ecology), several species are described as endemites (e.g., from Caspian Sea). |
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| Physiology and biochemistry: |
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| Distribution, endemism, problematic citations: |
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| Reference strain: |
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| Infrageneric scheme, species concept: |
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List of species:
Anabaena-like cluster A [see Anabaena]
Unclear taxa:
Excludenda: |
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| Keys: | ||||||||||
| List of stains: | ||||||||||
| Application technology: |
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Drawings: Komárek(1992) |
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Literature:
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