Porphyrosiphon F.T.Kützing ex M.Gomont, 1892

Holotype species: Porphyrosiphon notarisii Kützing ex Gomont

Original publication and holotype designation: Gomont, M. (1892). Monographie des Oscillariées (Nostocacées homocystées). Annales des Sciences Naturelles, Botanique, Série 7 15: 263-368, pls 6-14 [VI-XIV in text and expl. pl.].

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Description: Filamentous; filaments unbranched, usually slightly coiled, solitary or in microscopic to macroscopic clusters or compact mats, always with sheaths (only escaped hormogonia and germinating hormogonia without sheaths). Sheaths firm, thick, later always layered, tube-like, joined to the trichomes or slightly distant from them, colorless or colored with yellow-brown or reddish sheath-pigments (intensity of coloration dependent on the environmental conditions, type of coloration species-specific), open at the apex, containing one, very rarely two parallel trichomes; sheaths often characteristically widened and coiled after hormogonia release. Trichomes isopolar, 6-20 _m wide, cylindrical, with or without constrictions at the crosswalls, nonmotile (hormogonia motile ?). Cells isodiametric or slightly longer or shorter than wide, without aerotopes, sometimes with granular content or several prominent granules; end cells widely rounded, sometimes with thickened outer cell wall. Heterocytes and akinetes absent. Cell division crosswise, perpendicularly to the long axis of a trichome, daughter cells grow Å to the original size before the next division. All cells capable of division with the exception of apical ones (meristematic zones ?). Reproduction by variously long hormogonia (motile ?) which separate from trichomes by help of necridic cells. Mainly aerophytic and subaerophytic algae occurring on wet rocks (often in mountains), rarely on barks of trees, on the mud and in soil. Few species are described from marine littoral, several are known from periphyton in clear submersed localities.

Information contributed by: J. Komárek. The most recent alteration to this page was made on 2015-03-03 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 masculine.

Most recent taxonomic treatment adopted: Komárek, J., Kaštovský, J., Mares, J. & Johansen, J.R. (2014). Taxonomic classification of cyanoprokaryotes (cyanobacterial genera) 2014, using a polyphasic approach. Preslia 86: 295-335.

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Contributors
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=43297

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 03 March 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 02 October 2022

 
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