Katagnymene Lemmermann, 1899
Lectotype species: Katagnymene pelagica Lemmermann
Original publication: Lemmermann, E. (1899). Ergebnisse einer Reise nach dem Pacific. (H. Schauinsland 1896/97). Abhandlungen herausgegeben vom Naturwissenschaftlichen zu Bremen 16: 313-398, pls I-III.
Request PDFType designated in: Geitler, L. (1942). Schizophyta: Klasse Schizophyceae. In: Die natürlichen Pflanzenfamilien, Sweite Auflage. (Engler, A. & Prantl, K. Eds) Vol.1b, pp. 1-232. Leipzig: Wilhelm Engelmann.
Description: Filamentous; solitary trichomes or (extraordinary) small clusters of several trichomes, free-floating or free-living among other algae. Trichomes rarely straight, usually irregularly coiled up to screw-like coiled, 10-30 µm wide, usually with a limited growth, rarely long and multicelled, simple, uniserial, unbranched, without firm sheaths, but enveloped by a wide, colourless, sometimes diffluent mucilaginous envelope; trichomes at the ends not attenuated or only with few (-5) last cells slightly narrowed, sometimes with calyptra, at the cross walls constricted or unconstricted. Trichomes immotile, easy disintegrating into motile hormocytes (or with indistinct, slow and interrupted trembling without envelopes). Cells always shorter than wide, shortly cylindrical or barrel-shaped, without or with aerotopes (planktic species); thylakoids irregularly coiled with reticular arrangement through the cell. Heterocytes and akinetes absent.
Information contributed by: J. Komárek & M.D. Guiry. 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 feminine.
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: Cells divide by the crosswise fission, all cells capable to divide (but sometimes within short division zones), with the exception of apical ones. Division of trichomes in more or less constant distances, by a help of a special intercellular discs (special scarified cells ?). Fragmented trichomes remain sometimes chain-like connected by their ends, by rests of intercellular discs. Reproduction by a total disintegration of trichomes. Hormocytes germinate at both ends (isopolar).
According to Komárek (1992), there are two species, described from oceanic plankton (Pacific) and one from Central European moors, that correspond precisely to the generic diagnosis. Three others (clear freshwater reservoirs with water plants - Europe, and planktic in large water reservoirs in South Africa) grow in long filaments.
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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=47364
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 20 April 2024
