Pleurotaenium Nägeli, 1849

Holotype species: Pleurotaenium trabecula Nägeli

Original publication and holotype designation: Nägeli, C. (1849). Gattungen einzelliger Algen, physiologisch und systematisch bearbeitet. Neue Denkschriften der Allg. Schweizerischen Gesellschaft für die Gesammten Naturwissenschaften 10(7): i-viii, 1-139, pls I-VIII.

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Description: Cells usually solitary (some taxa filamentous), mostly elongate-cylindric (up to 1000 µm long), with shallow median constriction (isthmus) where semicell walls overlap. Semicells with basal swelling and truncate apex. Apex smooth or with ring of round or conical warts, or of short spines. Apex usually with terminal vacuole containing granules. Some species with whorls of mamillate protuberances, smooth or with spines, on each semicell. Cell walll with scattered pores. Chloroplast usually narrow, parietal bands, several per semicell, each with many pyrenoids. Nucleus in isthmus. Asexual constriction by cell division and new semicell morphogenesis typical of Cosmarium-type desmids (see Cosmarium). Sexual reproduction by heterothallic or homothallic conjugation. Homothallic conjugation often between asymmetric daughter cells from recent division. Gametes fuse between gametangia; zygospores spherical, sometimes with spines, or mamillate or conical protuberances. Karyogamy prior to zygospore germination, followed by meiosis. Several species cosmopolitan, usually in acidic, oligotrophic lacustrine environments or in swamps. Successful crosses involving three morphological species suggest single biological species present. Spontaneous production of diploid clones reported. Diploid/diploid and diploid/haploid crosses usually produced zygospores capable of germination.

Information contributed by: J.F. Gerrath. The most recent alteration to this page was made on 2013-09-12 by M.D. Guiry.

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

Most recent taxonomic treatment adopted: Guiry, M.D. (2013). Taxonomy and nomenclature of the Conjugatophyceae (=Zygnematophyceae). Algae. An International Journal of Algal Research 28: 1-29.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=43542

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 12 September 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 21 November 2024