Ascophyllum nodosum


Ascophyllum nodosum is a species of seaweed.


Empire: Eukaryota[1]
Kingdom: Chromista[1,2], Plantae[3,4]
Subkingdom: Harosa[2]
Infrakingdom: Heterokonta[2]
Subphylum: Phaeista[2]
Infraphylum: Limnista[2]
Superclass: Fucistia[2]
Phylum: Ochrophyta[1,2,4], Phaeophycophyta[3]
Class: Phaeophyceae[1,2,3], Ulvophyceae[4]
Subclass: Fucophycidae[1,2]
Order: Fucales[1,2,3]
Family: Fucaceae[1,2,3]
Genus: Ascophyllum[1,2,3]
Species: nodosum[1,3]

Original Name

Fucus nodosus[1,5]


Ascophylla laevigata[1,5,6], Ascophylla laevigatum[3], Ascophylla nodosa[1,2], Ascophyllum mackayi f. robertsonii[1,2], Ascophyllum robertsonii[1,2], Chordaria scorpioides[1,2], Fistularia mackayi[2,3], Fistularia nodosa[1,2,3], Fucodium nodosum[1,5,6], Fucus mackayi[3], Fucus nodosus[1,3,5], Fucus scorpioides[2,3], Halicoccus nodosus[1,2,5], Halidrys nodosa[5,6], Halidrys siliquosa var. minor[1,2], Ozothallia nodosa[1,5,6], Ozothallia vulgaris[1,2], Physocaulon nodosum[1,5,6]

Common Names

Asco[1], Bottle Kelp[5], Common Wrack, Dental Macroalgae, Dental Seaweed, Egg Wrack[1,7], Horse-Tang[5], Irish Seaweed[8], Knobbed Wrack[1,5], Knotted Kelp[4,9], Knotted Wrack[1,3,5], North Atlantic Kelp[10], Norwegian Kelp[4,9], Pig-Tang[5], Rockweed[4,5,7], Sea Whistle(s)[1,5], Wormweed[11], Yellow Tang[1,5], Yellow Wrack[12]

These common names may not be unique to the species Ascophyllum nodosum.

IUCN Status

Classified as “Not Rare/Scarce” by the International Union for Conservation of Nature.[13]


A large brown seaweed that prefers sheltered waters.[3,13] Male plants grow to 2 metres whilst female plants are smaller.[13] The species has long strap-like fronds[13,14] which are flexible and slimy, with large egg-shaped air bladders.[13]


Commonly found off the coast of Canada, America, Ireland, England, Scotland and Norway. Does not occur naturally in Australian waters.


See Nutrition Data


See The Many Uses and Benefits of Ascophyllum nodosum


  1. Guiry MD, Guiry GM. Ascophyllum nodosum (Linnaeus) Le Jolis [Internet]. AlgaeBase. 2019. Available from:
  2. Ascophyllum nodosum (Linnaeus) Le Jolis, 1863 [Internet]. WoRMS - World Register of Marine Species. Available from:
  3. California Department of Fish and Wildlife, Smithsonian Environmental Research Center (SERC). Ascophyllum nodosum [Internet]. National Exotic Marine and Estuarine Species Information System. Available from:
  4. Telnes K. Rockweed - Ascophyllum nodosum [Internet]. The Marine Flora & Fauna of Norway. Available from:
  5. Baardseth E. Synopsis of Biological Data on Knobbed Wrack Ascophyllum nodosum (Linnaeus) Le Jolis [Internet]. Food and Agriculture Organization of the United Nations; 1970. Available from:
  6. Sharp G. Ascophyllum nodosum and its harvesting in Eastern Canada [Internet]. Food and Agricultural Organization of the United Nations. Available from:
  7. Patel K. Ascophyllum nodosum [Internet]. 2018. Available from:
  8. Arramara. TitanTM Seaweed [Internet]. Available from:
  9. Wilson L. The Benefits of Kelp [Internet]. Dr. Wilson. Available from:
  10. Sea Kelp – Ascophyllum Nodosum [Internet]. New Age Nutrients. Available from:
  11. Sheehan TF. Ascophyllum nodosum- Wormweed [Internet]. Available from:
  12. Super Kelp [Internet]. Henry Blooms Health Products. Available from:
  13. Hill J, White N. Knotted wrack (Ascophyllum nodosum) [Internet]. Marine Life Information Network (MarLIN), The Marine Biological Association of the UK. 2008. Available from:
  14. Guiry MD. Ascophyllum nodosum (L.) Le Jolis [Internet]. The Seaweed Site. Available from:

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