Oocardium Nägeli, 1849
Holotype species: Oocardium stratum 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.
Request PDFDescription: Cells small (length 7-20 µm), in macroscopic (1-2 mm) colonies attached to solid substrata. Cells usually laterally asymmetrical, slightly compressed, with shallow median constriction (isthmus) where semicell walls overlap. Cells at ends of branched gelatinous stalks within encrusting calcareous tubes. Cell axis always at right angle to axis of tube (often incorrectly illustrated). Cell walls smooth, of two parts which overlap at median constriction. Usually one axial chloroplast with central pyrenoid per semicell (sometimes pressed to one side of semicell). Nucleus in isthmus between chloroplasts. Asexual reproduction by typical Cosmarium-type desmid cell division and new semicell formation (see Cosmarium). Sexual reproduction by conjugation, forming irregularly quadrangular zygospores with several mamillate projections to which empty gametangial walls remain attached.
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.
Comments: Rare, reported from streams in limestone areas of Europe, North America, and India. Colonies attached to stones, twigs, leaves, mosses, and feathers in calcium-rich streams (pH 7.5-9.3).
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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera,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=45917
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 18 April 2024
