Uronema Lagerheim, 1887

Holotype species: Uronema confervicola Lagerheim

Original publication and holotype designation: Lagerheim, G. (1887). Note sur l'Uronema, nouveau genre des algues d'eau douce. Malpigia 1: 517-523.

Description: Filaments uniseriate, unbranched, of limited growth, attached to substratum by hyaline gelatinous holdfast ("dermoid") apparently secreted by slightly tapering basal cell. Apical cell to a different degree acuminate. Cell wall thin and not lamellate. Cells cylindrical, elongated, closely adherent to one another, uninucleate. Chloroplast single and parietal, laminate to girdle-shaped, often encircling all, or nearly all of cell lumen, typically containing more than one pyrenoid, usually up to four. Incompletely encircling chloroplast lobed along longitudinal margin. Asexual reproduction by quadriflagellate zoospore arising 1(-2) per cell. Zoospores pyriform to oval, containing a cup-shaped parietal chloroplast with distinct stigma. In arrested zoosporogenesis, aplanospores arise, mostly germinating in the parental cell. Method of sexual reproduction unknown. Presence of biflagellate swarmers (gametes?) uncertain. Uronema cosmopolitan in freshwater, occurring as benthic alga in mesotrophic and eutrophic habitats such as stagnant and weakly streaming (open) waters, also in rice-fields and epiphytic on macro-algae (Oedogonium, Cladophora) and higher plants in pools. Cytological studies indicate chromosome numbers of n=12-18. A recently modified generic diagnosis of Ulothrix included Uronema. This can be rejected based on morphological features such as the discoid holdfast, acuminate apical cell and production of one zoospore per cell. In addition, ultrastructure of cell division (cell plate, phycoplast, plasmodesmata), and structural organization of flagellar apparatus in reproductive cells clearly places these algae in evolutionary lines Ulvophyceae and Chlorophyceae, respectively.

Information contributed by: G.M. Lokhorst. The most recent alteration to this page was made on 2023-11-19 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: Burova, O.V., Tsarenko, P.M., Kovalenko, O.V., Petlovany, O.A., Mikhailyuk, T.I. & Lilitska, G.G. (2011). Chaetophorales. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 264-278. Ruggell: A.R.A. Gantner Verlag K.-G.

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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=37842

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 19 November 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024