Aphanizomenon Morren ex Bornet & Flahault, 1886 '1888'

Lectotype species: Aphanizomenon flos-aquae Ralfs ex Bornet & Flahault

Original publication: Bornet, É. & Flahault, C. (1886 '1888'). Revision des Nostocacées hétérocystées contenues dans les principaux herbiers de France (quatrième et dernier fragment). Annales des Sciences Naturelles, Botanique, Septième Série 7: 177-262.

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Type designated in: Kirchner, O. (1898). Schizophyta: Schizophyceae. In: Die natürlichen Pflanzenfamilien. (Engler, A. & Prantl, K. Eds) Vol. 1(1), pp. 45-92, figures 48-62. Leipzig: Wilhelm Engelmann.

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Description: Filaments free-floating, solitary, in few species joined into fascicle-like, microscopic or macroscopic (up to 2 cm long) colonies with trichomes oriented in parallel; trichomes straight, slightly curved or slightly coiled, cylindrical or sharply or continually tapering to the ends, at crosswalls constricted or not, always without firm sheaths, several species with very fine mucilaginous, diffluent and colorless envelopes (?); trichomes uniseriate, 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 paraheterocytically, solitary or in short rows (in 2 or 3), close to heterocytes or slightly distant from them, usually in asymmetrical position in a trichome. Vegetative cells divide transversely and grow to original size before the next division; terminal cells do not divide; without meristematic zones. Reproduction by trichome dissociation and by akinetes. Almost all species are planktonic, sometimes forming characteristic water blooms, the well-known type species (A. flos-aquae) is important in managed fish ponds and in lakes; mainly are distributed in eutrophic reservoirs, few species are halophilic. All species have limited areas of distribution (and possess characteristic species ecology), several species are described as endemic (e.g., from Caspian Sea).

Information contributed by: J. Komárek. The most recent alteration to this page was made on 2023-03-06 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Gender: This genus name is currently treated as neuter.

Most recent taxonomic treatment adopted: Strunecký, O., Ivanova, A.P. & Mares, J. (2022 '2023'). An updated classification of cyanobacterial orders and families based on phylogenomic and polyphasic analysis (Review). Journal of Phycology 59(1): 12-51.

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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in CD format. These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above. The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.

Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.

Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=43592

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 06 March 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 18 May 2024

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