Valoniopsis Børgesen, 1934

Holotype species: Valoniopsis pachynema (G.Martens) Børgesen

Original publication and holotype designation: Børgesen, F. (1934). Some marine algae from the northern part of the Arabian sea with remarks on their geographical distribution. Kongelige Danske Videnskabernes Selskab, Biologiske Meddelelser 11(6): 1-72, 8 figs, 2 plates.

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Description: Thallus composed of interwoven filiform cells forming mats, 1-5 cm thick. Siphons 1-1.5 mm diameter, to 5 mm long. Apical orientation increasingly obliterated by irregular branching. Annular constrictions not present. Branches straight and reflexed, septate only at branch points. Branching initiated from lenticular cells, often in twos or threes from apex, and laterally in basipetal direction; never from protrusions. Rhizoid well developed from which new uprights can arise. Branch tips in contact with substratum forming adventitious rhizoidal cells. Structural reinforcement of the thallus by interweaving of siphons. Tenacular cells absent. Cell division by lenticular cells in main axes; by centripetal invagination in rhizoid. Cells with numerous discoid chloroplasts, each with single pyrenoid bisected by traversing thylakoids and covered with starch sheath. Life presumed similar to other cladophoralean algae. Haploid chromosome number of 20. Valoniopsis is a common tropical reef flat genus often found in associated with Anadyomene and Microdictyon in areas of strong water motion. Genus used as a model system for studies of cytoskeleton and wound-healing. Valoniopsis sometimes confused with Cladophoropsis but that genus has septate and nonseptate branches, and no lenticular cells. The taxonomic position of the genus within the Siphonocladales-Cladophorales complex remains unclear.

Information contributed by: J.L. Olsen. The most recent alteration to this page was made on 2011-08-29 by M.D. Guiry.

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

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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. 29 August 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024