Chorda Stackhouse, 1797

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.

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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 2022-06-26 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

Most recent taxonomic treatment adopted: Kawai, H., Hanyuda, Y., Mumford, T. & Waaland, J.R. (2015). An introduced population of Chorda asiatica (Chordaceae, Laminariales) in Puget Sound, Pacific coast of North America. Phycological Research 63: 154-158, 3 figs. 1 table.

Comments: Widely distributed in cold and temperate area of northern hemisphere.

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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.

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 26 June 2022. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 23 July 2024

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