A red seaweed (Phycodrys rubens)

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



A small red alga, up to 15 cm tall, with a leaf-like frond, with midrib, lateral veins and serrated margin that give the impression of an oak leaf. The disc-like holdfast gives rise to a short toughened stipe. In winter the frond wears away due to a combination of cessation of growth and wave action, leaving just the mid-rib, the blade growing back in spring. Phycodrys rubens is light crimson in colour and can be distinguished from the similarly leaf-like Delesseria sanguinea by the deeply serrated frond and branching habit.

Recorded distribution in Britain and Ireland

Commonly sublittoral present on rocky substrata in northern Britain but more widely distributed on kelp stipes. Absent from parts of the east coast where turbid waters and a lack of suitable substrata preclude its growth.

Global distribution



It is common in lower shore rock pools and the subtidal, growing on both rock and on the stipes of Laminaria hyperborea to a depth of up to 30 m.

Depth range


Identifying features

  • Up to 15 cm tall.
  • Leaf-like frond suggestive of an oak leaf and deeply serrated.
  • Disc-like holdfast.
  • Light crimson in colour.
  • Fronds have a branching habit.

Additional information

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Listed by

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  1. 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.

  2. 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

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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Manx Biological Recording Partnership, 2018. Isle of Man historical wildlife records 1990 to 1994. Occurrence dataset:https://doi.org/10.15468/aru16v accessed via GBIF.org on 2018-10-01.

  9. 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.

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

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

  12. OBIS (Ocean Biodiversity Information System),  2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. www.iobis.org. Accessed: 2023-09-27

  13. 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.

  14. 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.


This review can be cited as:

Pizzolla, P.F 2007. Phycodrys rubens A red seaweed. 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 27-09-2023]. Available from: https://www.marlin.ac.uk/species/detail/1457

Last Updated: 07/06/2007