Holotype species: Chorda filum (Linnaeus) Stackhouse
Original publication and holotype designation: Stackhouse, J. (1797). Nereis britannica; continens species omnes fucorum in insulis britannicis crescentium: descriptione latine et anglico, necnon iconibus ad vivum depictis... Fasc. 2. pp. ix-xxiv, 31-70, pls IX-XIII. Bathoniae [Bath] & Londini [London]: S. Hazard; J. White.
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Silberfeld, T., Rousseau, F. & Reviers, B. de (2014). An updated classification of brown algae (Ochrophyta, Phaeophyceae). Cryptogamie Algologie 35(2): 117-156.
Description: Annual, growing on small shells or epilithic, subtidal. Sporophyte gregarious on small discoid holdfast, up to several meters in length, olive to brown, cord-shaped, cylindrical, solid when young later becoming hollow, composed of 3-8 cell rows of medullary layer, 4-6 celled paraphyses and narrow obovate unilocular sporangia. Trumpet-shaped hyphae present in the central part of thalli. Phaeophycean hairs (C. filum) or assimilatory hairs (C. tomentosa) abundant. No special mucilagenous organs. Chloroplasts many, discoid, without pyrenoids. Intercalary meristem present or absent. Plurilocular sporangia not formed on erect thalli. Life history heteromorphic between macroscopic polystichous sporophyte and branched filamentous gametophyte. Gametophytes oogamous, dioecious but sexually monomorphic (C. filum) or monoecious (C. tomentosa). Zoospores from unilocular sporangia teardrop-shaped, biflagellated with longer anterior flagellum, with a stigma. Germination unipolar forming emptied embryospore. Antheridia formed on fertile branches, often in cluster. Sperm almost colorless containing several reduced chloroplasts without stigma, with longer posterior flagella. Oogonia terminal on fertile branches. Zygotes develop attached at the mouth of the oogonia. First several divisions occur transversely, then become polystichous and terete. Sexual pheromone reported to be multifidene in C. tomentosa.
Information contributed by: H. Kawai. The most recent alteration to this page was made on 21 Jun 2014 by M.D. Guiry.
Comments: Widely distributed in cold and temperate area of northern hemisphere.
Numbers of names and species: There are 14 species names in the database at present, as well as 15 infraspecific names. Of the species names, 5 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.
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: 21 June 2014 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=37367
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 13 December 2018.