Biodiversity & Conservation

Sea lettuce - Ulva lactuca


Ulva lactuca

Image Steve Trewhella - Ulva lactuca. Image width ca 6 cm.
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Distribution map

Ulva lactuca 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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Ulva lactuca is not listed under any importance categories.


Taxonomy icon Taxonomy Taxon English term
Phylum Chlorophyta Green seaweeds and stoneworts
Class Ulvophyceae
Authority Linnaeus
Recent synonyms None
Map icon Recorded Distribution in Britain and Ireland An ubiquitous plant found on all but the most exposed rocky shores, but is probably under-recorded in Ireland.
Habitat information icon Habitat information The sea lettuce is found at all levels of the intertidal, although in more northerly latitudes and in brackish habitats it is found in the shallow sublittoral. In very sheltered conditions, plants that have become detached from the substrate can continue to grow, forming extensive floating communities. The plant tolerates brackish conditions and can be found on suitable substrata in estuaries.
Text page icon Description A small green alga (up to 30 cm across) with a broad, crumpled frond that is tough, translucent and membranous. It is attached to rock via a small hold-fast .
Identifying features
  • Up to 30 cm across.
  • Frond broad and crumpled, that is tough, translucent and membranous.
  • Disc like holdfast.
  • Green to dark green in colour.
Additional information icon Additional information Ulva is sometimes eaten as "green laver", but it is considered inferior to purple laver.

This review can be cited as follows:

Paolo Pizzolla 2008. Ulva lactuca. Sea lettuce. Marine Life Information Network: Biology and Sensitivity Key Information Sub-programme [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 29/08/2014]. Available from: <http://www.marlin.ac.uk/speciesinformation.php?speciesID=4541>