Biodiversity & Conservation

A red seaweed - Polysiphonia lanosa

A red seaweed

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Distribution map

Polysiphonia lanosa recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

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Polysiphonia lanosa is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Rhodophyta Red seaweeds
Class Florideophyceae
Authority (Linneus) Tandy
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Found associated with Ascophyllum nodosum on suitable substrata on all coasts of Britain and Ireland.
Habitat information icon Habitat information 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.
Text page icon Description 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.
Identifying features
  • Reddish brown filamentous alga.
  • An epiphyte of Ascophyllum nodosum, on which they look like 'pom poms'.
Additional information icon Additional information No text entered

This review can be cited as follows:

Paolo Pizzolla 2008. Polysiphonia lanosa. A red seaweed. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 26/11/2015]. Available from: <>