Raphidonemopsis T. Deason, 1969

Holotype species: Raphidonemopsis sessilis Deason

Description: Solitary or weakly filamentous, 2-8 celled, attached by short filiform holdfast projecting from very polar end of attenuated basal cell. Apical cell pointed or rounded. Cell walls thin, hyaline, without mucilage. Cells cylindrical, straight, sigmoid or arched, sometimes abruptly narrowed at both ends. Chloroplast single and parietal, without pyrenoids. Multiplication of filaments only by vegetative cell division; method of sexual reproduction unknown. Raphidonemopsis found as a spontaneously-growing alga in culture prepared from soil (USA), and in nature in mucous subaerial periphyton on wet wood beneath waterfall in central Europe. Raphiodonemopsis shows variable growth habit determined by external factors, and in culture, filaments formed. Raphidonemopsis closely related to Koliella based on cell shape, differing in sessile habit. In addition, Raphidonemopsis and Hormidiella produce filiform holdfasts. Ultrastructurally, pattern of cell division in Raphidonemopsis basically similar to Koliella, Stichococcus and Klebsormidium. For example, dividing nuclei have open spindle, dictyosomes form spindle poles, daughter nuclei widely separated, and septum development occurs via centripetal ingrowth of cleavage furrow without a phycoplast.

Information contributed by: G.M. Lokhorst. The most recent alteration to this page was made on 2016-02-27 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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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. 27 February 2016. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 18 April 2024