152,885 species and infraspecific names are in the database, 20,939 images, 59,127 bibliographic items, 408,269 distributional records.

Gigartina Stackhouse, 1809

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Biliphyta
Phylum Rhodophyta
Subphylum Eurhodophytina
Class Florideophyceae
Subclass Rhodymeniophycidae
Order Gigartinales
Family Gigartinaceae

Holotype species: Gigartina pistillata (S.G.Gmelin) Stackhouse

Original publication and holotype designation: Stackhouse, J. (1809). Tentamen marino-cryptogamicum, ordinem novum; in genera et species distributum, in Classe XXIVta Linnaei sistens. Mémoires de la Société Imperiale des Naturalistes de Moscou 2: [50]-97.
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Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Schneider, C.W. & Wynne, M.J. (2007). A synoptic review of the classification of red algal genera a half a century after Kylin's "Die Gattungen der Rhodophyceen". Botanica Marina 50: 197-249.

Nomenclatural notes
Monotypic when first introduced. - (23 Jan 2017) - M.D. Guiry

Description: Plants of the largest species reach over 100 cm in length. Thalli for the most part are erect and range from broadly foliose to narrowly pinnate. A few species form entangled clumps anchored by multiple haptera. Cystocarps are 95 conspicuously protuberant on marginal and/or surface proliferations and contain a filamentous hull surrounding the carposporophyte. Ultrastructural studies of cells involved in the production of carposporophytes and carposporangia have been made by Tsekos and Schnepf (1983) and Tsekos (1983). Tetrasporangia form in intercalary chains at the border of cortex and medulla. Guiry (1984) compared the formation of tetrasporangial sori in the type species with with other members of the genus and concluded that the differences point to there being more than one genus involved in the complex.

Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 23 Jan 2017 by M.D. Guiry.

Comments: Because of their commercial importance, Gigartina spp. have been subjects of much recent study. The ecology of estuarine and open coast populations of the one northeastern Atlantic species was investigated by Mathieson and Tveter (1976) in relation to amounts and quality of their carrageenan. Studies of photoperiodic responses (Guiry 1984; Guiry and Cunningham 1984) have identified reproductive "windows" and suggested explanations for the increasingly exclusive vegetative propagation, as opposed to gametangial and tetrasporangial production, in high-latitude populations of a widespread European species. Genetic determination of branching patterns and upper limits of temperature tolerance have been established for several species by Guiry et al. (1987). Numerous carrageenan analyses (e.g., Parsons et al. 1977; West and Guiry 1982) have been made, as well as studies demonstrating that both normal "Polysiphonia" (Guiry 1984; Guiry et al. 1987; West and Guiry 1982) and apomictic (Chen et al. 1974; Masuda and Uchida 1976) life histories occur in the genus. The feasibility of cultivating species on artificial substrata has been assessed by Mumford and Waaland (1980) and shown to have commercial potential. Distribution: Worldwide throughout cool to cold temperate seas, a very few species occurring in the subtropics. Centers of particularly rich species diversity are California, Japan, New Zealand, Chile, and South Africa.

Numbers of names and species: There are 307 species names in the database at present, as well as 109 infraspecific names. Of the species names, 41 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.

References
Hommersand, M.H., Guiry, M.D., Fredericq, S. & Leister, G.L. (1993). New perspectives in the taxonomy of the Gigartinaceae (Gigartinales, Rhodophyta). Proceedings of the International Seaweed Symposium 14: 105-120, 41 figs.

Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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.

Created: 28 December 2000 by M.D. Guiry

Verified by: 23 January 2017 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=33000

Citing AlgaeBase
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 September 2018.

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