149,969 species and infraspecific names are in the database, 20,386 images, 57,652 bibliographic items, 380,224 distributional records.

Planctonema Schmidle, 1903

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridiplantae
Infrakingdom Chlorophyta infrakingdom
Phylum Chlorophyta
Subphylum Chlorophytina
Class Trebouxiophyceae
Order Chlorellales
Family Oocystaceae

Holotype species: Planctonema lauterbornii Schmidle

Original publication and holotype designation: Schmidle, W. (1903). Bemerkungen zu einigen Süsswasseraigen. Berichte der Deutschen Botanischen Gessellschaft 21: 346-355, pl. XVIII (separately).
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Taxonomic status: currently recognized as a distinct genus.

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.

Taxonomic notes
Not included in the Oocystaceae by Liu et al., 2017: fig. 6. - (8 Sep 2017) - Wendy Guiry

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 3 Mar 2012 by M.D. Guiry.

Numbers of names and species: There are 4 species names in the database at present, of which 1 has been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..

Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):

Planctonema aenigmaticum (Skuja) ? P 
Planctonema gelatinosum X.Liu, H.Zhu, B.Liu, Z.Hu & G.Liu C 
Planctonema lauterbornii Schmidle S - type
Planctonema subtilissimum (Lagerheim) Hällfors S 

References
Cambra Sánchez, J., Álvarez Cobelas, M. & Aboal Sanjurjo, M. (1998). Lista florística y bibliográfica de los clorófitos (Chlorophyta) de la Península Ibérica, Islas Baleares e Islas Canarias. pp. 1-614. Burgos: Asociación Española de Limnología.

Pascher, A. (1939). Heterokonten. In: Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. (Rabenhorst, L. Eds) Vol. 11 Teil 6, pp. 833-1092, [iii-x]. Leipzig: Akademische Verlagsgesellschaft.

Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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.

Created: 11 April 2002 by M.D. Guiry

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Linking to this page: http://algaebase.org/search/genus/detail/?genus_id=Xacb72c1af259cd7e

Citing AlgaeBase
Please cite this record as:
Guiry, M.D. & Guiry, G.M. 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 24 November 2017.

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