Planctonema Schmidle, 1903

Holotype species: Planctonema lauterbornii Schmidle

Original publication and holotype designation: Schmidle, W. (1903). Bemerkungen zu einigen Süsswasseralgen. Berichte der Deutschen Botanischen Gessellschaft 21: 346-355, pl. XVIII (separately).

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Description: Filaments short, uniseriate enclosed by common mucilaginous sheath of variable thickness, without polarity and free-floating. Individual cells dispersed in loose linear arrangement, almost equidistant, or more usually cells united end to end in separate pairs. Space between pairs filled with mucilage. Cells cylindrical, containing parietal, plate-like chloroplast with(out?) pyrenoids and starch. Nucleus in median constriction of chloroplast. Vacuoles with conspicuous oil-globules marking cell poles. Vegetative propagation by fragmentation of filaments; method of sexual reproduction unknown. Planctonema planktonic in various freshwater habitats in Europe and Japan. Taxonomic position of Planctonema uncertain, with contradictory reports based on light microscopy, e.g., pyrenoid presence questionable and chloroplasts described as both axillary and parietal. In one isolate, however, ultrastructural studies showed a pyrenoid and a cell walls with two layers an inner membrane only covering individual cell, and an outer membrane surrounding adjacent cells.

Information contributed by: G.M. Lokhorst. The most recent alteration to this page was made on 2012-03-03 by M.D. Guiry.

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

Most recent taxonomic treatment adopted: John, D.M. (2002). Orders Chaetophorales, Klebshormidiales, Microsporales, Ulotrichales. In: The Freshwater Algal Flora of the British Isles. An identification guide to freshwater and terrestrial algae. (John, D.M., Whitton, B.A. & Brook, A.J. Eds), pp. 433-468. Cambridge: Cambridge University Press.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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.

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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 03 March 2012. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 23 November 2024