Desmidium C.Agardh ex Ralfs, 1848
Lectotype species: Desmidium swartzii C.Agardh ex Ralfs
Original publication: Ralfs, J. (1848). The British Desmidieae The drawings by Edward Jenner, A.L.S. pp. [i]-xxii, [i], [1]-226, 35 pls. London: Reeve, Benham & Reeve, King William Street, Strand.
Request PDFType designated in: 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.
Description: Cells longer or shorter than broad, with distinct or indistinct median constriction (isthmus) where semicell walls overlap. Cells united into long filaments, either by entire apical surface of adjacent cells or by apical processes. Cells 3-5 angled or elliptical in apical view. Cell angles usually slightly offset on each semicell, producing helical pattern of angles along filament. Cell wall smooth with pores in transverse rows or scattered. One chloroplast per semicell, stellate in end view, with central pyrenoid, or with pyrenoid in each lobe. Nucleus at isthmus between chloroplasts. Asexual reproduction by cell division with formation of replicate division septum. Division septum (primary wall) develops cylindrical template perpendicular to septum, which delimits semicell apex or apical processes for each daughter semicell. Secondary wall laid down on primary wall template forms folded (replicate) wall region. Parts of primary wall split or disintegrate, except on surfaces which will maintain integrity of filament. Semicell expansion causes folded secondary wall regions to straighten out to produce mature morphology. Sexual reproduction by conjugation. Filaments come together within gelatinous envelope; usually break apart before cells pair. Gametes fuse between gametangia. Mature zygospores spherical to ellipsoid, smooth-walled or with rounded warts. Desmidium cosmopolitan; several common, widespread species, usually in oligotrophic, acidic lakes and bogs.
Information contributed by: J.F. Gerrath. The most recent alteration to this page was made on 2022-09-26 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 neuter.
Most recent taxonomic treatment adopted: Hess, S., Williams, S.K., Busch, A., Irisarri, I., Delwiche, C.F., de Vries, S., Darienko, T., Roger, A.J., Archibald, J.M., Buschmann, H., von Schwartzenberg, K. & de Vries, J. (2022). A phylogenomically informed five-order system for the closest relatives of land plants. Current Biology 32: 1-10.
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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=43528
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 26 September 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 25 November 2024
