Xenococcus Thuret, 1880

Holotype species: Xenococcus schousboei Thuret

Original publication and holotype designation: Bornet, É. & Thuret, G. (1880). Notes algologiques recueil d'observations sur les algues. Fasc. 2. pp. 73-196, pls XXVI-L. Paris: G. Masson.

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Description: Unicellular-colonial; colonies attached to the substrate, flat to pseudoparenchymatous, circular or elongated in outline, 1-3(4)-layered, microscopic, later to macroscopically visible (point-like), composed of very densely agglomerated cells. Cells more or less oval, irregular, polygonal with rounded corners, or in the upper layer of a colony slightly pyriform, enveloped by colorless, thin, firm, usually slightly layered, tight, mucilaginous sheath; cell content blue-green, greyish or reddish. Division of cells irregular, in more directions perpendicular to the substrate, but later also crosswise (parallel to the substrate); cells do not grow into original shape before the next division. From cells in the upper part of a colony arise sometimes nanocytes, which serve mainly to the reproduction.

Information contributed by: J. Komárek. The most recent alteration to this page was made on 2023-03-03 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: Strunecký, O., Ivanova, A.P. & Mares, J. (2022 '2023'). An updated classification of cyanobacterial orders and families based on phylogenomic and polyphasic analysis (Review). Journal of Phycology 59(1): 12-51.

Comments: Attached to different substrates (stones, algae, water plants) in different water biotopes; several species are known from alpine streams, another one from the marine littoral. Many species have probably the special areas of distribution. A poorly known genus.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=43073

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 03 March 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 19 April 2024