Wrack siphon weed (Vertebrata lanosa)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



A small reddish-brown filamentous alga most commonly associated with the fucoid alga Ascophyllum nodosum. The filaments are made up of a ring of 12 -24 elongated cells or siphons surrounding a central siphon. The plant is found wherever the host is common. Polysiphonia lanosa has occasionally been recorded as an epiphyte on Fucus serratus and Fucus vesiculosus and, more rarely, on rocky substrata.

Recorded distribution in Britain and Ireland

Found associated with Ascophyllum nodosum on suitable substrata on all coasts of Britain and Ireland.

Global distribution



Lives as epiphyte of Ascophyllum nodosum and more rarely on other fucoids. Common on the mid-littoral of rocky shores, but not extending far into estuaries.

Depth range


Identifying features

  • Reddish brown filamentous alga.
  • An epiphyte of Ascophyllum nodosum, on which they look like 'pom poms'.

Additional information

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Listed by

- none -


  1. Dickinson, C.I., 1963. British seaweeds. London & Frome: Butler & Tanner Ltd.

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  3. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  4. JNCC (Joint Nature Conservation Committee), 1999. Marine Environment Resource Mapping And Information Database (MERMAID): Marine Nature Conservation Review Survey Database. [on-line] http://www.jncc.gov.uk/mermaid


  1. Bristol Regional Environmental Records Centre, 2017. BRERC species records within last 15 years. Occurrence dataset: https://doi.org/10.15468/vntgox accessed via GBIF.org on 2018-09-25.

  2. Centre for Environmental Data and Recording, 2018. Ulster Museum Marine Surveys of Northern Ireland Coastal Waters. Occurrence dataset https://www.nmni.com/CEDaR/CEDaR-Centre-for-Environmental-Data-and-Recording.aspx accessed via NBNAtlas.org on 2018-09-25.

  3. Cofnod – North Wales Environmental Information Service, 2018. Miscellaneous records held on the Cofnod database. Occurrence dataset: https://doi.org/10.15468/hcgqsi accessed via GBIF.org on 2018-09-25.

  4. Environmental Records Information Centre North East, 2018. ERIC NE Combined dataset to 2017. Occurrence dataset: http://www.ericnortheast.org.ukl accessed via NBNAtlas.org on 2018-09-38

  5. Fenwick, 2018. Aphotomarine. Occurrence dataset http://www.aphotomarine.com/index.html Accessed via NBNAtlas.org on 2018-10-01

  6. Fife Nature Records Centre, 2018. St Andrews BioBlitz 2014. Occurrence dataset: https://doi.org/10.15468/erweal accessed via GBIF.org on 2018-09-27.

  7. Fife Nature Records Centre, 2018. St Andrews BioBlitz 2015. Occurrence dataset: https://doi.org/10.15468/xtrbvy accessed via GBIF.org on 2018-09-27.

  8. Fife Nature Records Centre, 2018. St Andrews BioBlitz 2016. Occurrence dataset: https://doi.org/10.15468/146yiz accessed via GBIF.org on 2018-09-27.

  9. Kent Wildlife Trust, 2018. Kent Wildlife Trust Shoresearch Intertidal Survey 2004 onwards. Occurrence dataset: https://www.kentwildlifetrust.org.uk/ accessed via NBNAtlas.org on 2018-10-01.

  10. Manx Biological Recording Partnership, 2017. Isle of Man wildlife records from 01/01/2000 to 13/02/2017. Occurrence dataset: https://doi.org/10.15468/mopwow accessed via GBIF.org on 2018-10-01.

  11. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1995 to 1999. Occurrence dataset: https://doi.org/10.15468/lo2tge accessed via GBIF.org on 2018-10-01.

  12. Merseyside BioBank., 2018. Merseyside BioBank (unverified). Occurrence dataset: https://doi.org/10.15468/iou2ld accessed via GBIF.org on 2018-10-01.

  13. National Trust, 2017. National Trust Species Records. Occurrence dataset: https://doi.org/10.15468/opc6g1 accessed via GBIF.org on 2018-10-01.

  14. NBN (National Biodiversity Network) Atlas. Available from: https://www.nbnatlas.org.

  15. OBIS (Ocean Biodiversity Information System),  2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-09-21

  16. Outer Hebrides Biological Recording, 2018. Non-vascular Plants, Outer Hebrides. Occurrence dataset: https://doi.org/10.15468/goidos accessed via GBIF.org on 2018-10-01.

  17. Royal Botanic Garden Edinburgh, 2018. Royal Botanic Garden Edinburgh Herbarium (E). Occurrence dataset: https://doi.org/10.15468/ypoair accessed via GBIF.org on 2018-10-02.

  18. South East Wales Biodiversity Records Centre, 2018. SEWBReC Algae and allied species (South East Wales). Occurrence dataset: https://doi.org/10.15468/55albd accessed via GBIF.org on 2018-10-02.

  19. South East Wales Biodiversity Records Centre, 2018. Dr Mary Gillham Archive Project. Occurance dataset: http://www.sewbrec.org.uk/ accessed via NBNAtlas.org on 2018-10-02

  20. Yorkshire Wildlife Trust, 2018. Yorkshire Wildlife Trust Shoresearch. Occurrence dataset: https://doi.org/10.15468/1nw3ch accessed via GBIF.org on 2018-10-02.


This review can be cited as:

Pizzolla, P.F 2008. Vertebrata lanosa Wrack siphon weed. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 21-09-2023]. Available from: https://www.marlin.ac.uk/species/detail/1452

Last Updated: 29/05/2008