155,613 species and infraspecific names are in the database, 21,916 images, 60,166 bibliographic items, 438,693 distributional records.

Gracilariopsis E.Y.Dawson, 1949

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Biliphyta
Phylum Rhodophyta
Subphylum Eurhodophytina
Class Florideophyceae
Subclass Rhodymeniophycidae
Order Gracilariales
Family Gracilariaceae
Subfamily Gracilarioideae
Tribe Gracilariopsideae

Holotype species: Gracilariopsis sjoestedtii (Kylin) E.Y.Dawson

Currently accepted name for the type species: Gracilariopsis andersonii (Grunow) E.Y.Dawson

Original publication and holotype designation: Dawson, E.Y. (1949). Studies of the northeast Pacific Gracilariaceae. Occasional Papers of the Allan Hancock Foundation 7: 1-105, 25 plates.

Taxonomic status: currently recognized as a distinct genus.

Gender: This genus name is currently treated as feminine.

Most recent taxonomic treatment adopted: Gurgel, C.F.D., Liao, L.M., Fredericq, S. & Hommersand, M.H. (2003). Systematics of Gracilariopsis (Gracilariales, Rhodophyta) based on rbcL sequence analyses and morphological evidence. Journal of Phycology 39: 154-171.

Description: Plants of the largest species reach 40 cm in length. Thalli are terete and erect from a discoid holdfast. Carpogonial branches are as for the family, as is the formation of a primary fusion cell composed of the carpogonium and up to six adjacent sterile gametophytic cells. A secondary fusion cell is absent, the gonimoblasts arising from the primary fusion cell. Secondary pit connections only link the basal cells of the carposporophyte with specially modified cells on the floor of the cystocarp cavity, there being no "nutrient tubular cells" as occur. Carposporangia form in chains at the periphery of the sterile gonimoblasts. Spermatangial mother cells occur in pairs or groups of 3 on outer cortical bearing cells and each cuts off a single spermatangium by a transverse division.

Information contributed by: G.T. Kraft & M.D. Guiry. The most recent alteration to this page was made on 5 Nov 2018 by M.D. Guiry.

Comments: Long considered a genus indistinguishable from Gracilaria, Gracilariopsis has been reinstated by Fredericq and Hommersand (1989), who emphasize four differences between the two genera which they consider important. Fusion cells in Gracilariopsis incorporate only the cells immediately flanking the carpogonium, whereas in Gracilaria additional gametophytic cells are later added. Nutrient tubular cells characteristic of Gracilaria are lacking in Gracilariopsis, and the carposporangial chains of the latter are straighter and more regularly organized. Spermatangial mother cells are formed from superficial cortical cells in Gracilariopsis, whereas in Gracilaria they are said to arise from adventitious filaments arising on subsurface (i.e. intercalary) cortical cells.

Numbers of names and species: There are 32 species names in the database at present, of which 25 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.

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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.

Created: 28 December 2000 by M.D. Guiry

Verified by: 05 November 2018 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=34341

Citing AlgaeBase
Please cite this record as:
M.D. 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 26 June 2019.

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