Geminella Turpin, 1828
Holotype species: Geminella interrupta Turpin
Original publication and holotype designation: Turpin, P.J.F. (1828). De la description de plusieurs genres et espèces nouvelles très remarquables, découverte parmi les productions végétales et microscopiques. Mémoires du Musée d'Histoire Naturelle 16: 295-344, pl. 13 ["15"].
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Tsarenko, P.M. (2011). Trebouxiophyceae. In: Algae of Ukraine: diversity, nomenclature, taxonomy, ecology and geography. Volume 3: Chlorophyta. (Tsarenko, P.M., Wasser, S.P. & Nevo, E. Eds), pp. 61-108. Ruggell: A.R.A. Gantner Verlag K.-G..
Description: Free-floating or sessile filaments surrounded by homogeneous mucilaginous envelope of considerable thickness, without polar differentiation. Filaments uniseriate, of different length. Individual cells dispersed in loose linear arrangement, equidistant, or in pairs, or cells united end to end, slightly meeting at poles. Cells basically cylindrical and elongated with broadly rounded ends, sometimes slightly inflated and ellipsoid to oval. Chloroplasts single and parietal, girdle-shaped or laminate, often restricted to equatorial cell region and partially encircling protoplast, with one central pyrenoid. Propagation via fragmentation of filaments. Infrequent cleavage in several directions leading to irregular accumulations of cells finally discharged from parental filament following disintegration of common mucilaginous wall. Zoospores not definitely known. Akinetes with thick brown walls. Method of sexual reproduction unknown. Geminella cosmopolitan, mostly planktonic in various freshwater habitats including swamps and shallow waters of lakes and ponds; also reported from periphyton of Lemna and from terrestrial habitats. The close resemblance of Geminella to other (pseudo)filamentous genera also equipped with mucilaginous sheath surrounding filaments precludes an explicit taxonomic delimitation. In addition, extensive comparative light and electron microscopic studies are required to clarify species delimitation.
Information contributed by: G.M. Lokhorst. The most recent alteration to this page was made on 27 Apr 2012 by Michael Guiry.
Numbers of names and species: There are 22 species names in the database at present, as well as 6 infraspecific names. Of the species names, 15 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..
Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):
Click here to also show infraspecific names in the list below.
Cambra Sánchez, J., Álvarez Cobelas, M. & Aboal Sanjurjo, M. (1998). Lista florística y bibliográfica de los clorófitos (Chlorophyta) de la Península Ibérica, Islas Baleares e Islas Canarias. pp. 1-614. Burgos: Asociación Española de Limnología.
Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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.
Created: 28 December 2000 by M.D. Guiry
Verified by: 27 April 2012 by Michael Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=37845
Please cite this record as:
Michael Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 September 2019.