Biodiversity & Conservation

Velvet horn - Codium tomentosum

Codium tomentosum

Image John Kelly - Codium tomentosum with Fucus serratus and red seaweeds. Image width ca XX cm.
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Distribution map

Codium tomentosum recorded (dark blue bullet) and expected (light blue bullet) distribution in Britain and Ireland (see below)

Why do the maps differ?

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Codium tomentosum is not listed under any importance categories.

Taxonomy icon Taxonomy Taxon English term
Phylum Chlorophyta Green seaweeds and stoneworts
Class Bryopsidophyceae
Authority Stackhouse
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland Codium tomentosum occurs mainly in the south west of the UK and is becoming quite rare. Both pollution and competition with Codium fragile have been suggested as potential causes of its decline.
Habitat information icon Habitat information It attaches to exposed rocks and occurs in rock pools on the lower shore.
Text page icon Description A small green alga (up to 30 cm long) with a dichotomously branched, cylindrical frond. The frond is solid and spongy with a felt-like touch and has many colourless hairs which can be seen when the plant is immersed in water. The holdfast is disc-like and formed from many fine threads.
Identifying features
  • Small green seaweed, up to 30 cm long.
  • Dichotomously branching with a cylindrical frond.
  • Felt-like to the touch.
  • Disc like holdfast made from fine threads.
    Additional information icon Additional information Codium tomentosum can be confused with Codium fragile. However, Codium tomentosum tends to have a more slender frond with rounded tips whereas Codium fragile has pointed tips to the frond.

    This review can be cited as follows:

    Paolo Pizzolla 2007. Codium tomentosum. Velvet horn. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 09/02/2010]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=3020>