information on the biology of species and the ecology of habitats found around the coasts and seas of the British Isles

A green seaweed (Ulva linza)

Distribution data supplied by the Ocean Biogeographic Information System (OBIS). To interrogate UK data visit the NBN Atlas.
Only coastal and marine records shown



Ulva linza is a large, ribbon-like species of green seaweed that may reach up to 30 cm in length. The thalli are unbranched and often have a frilled margin. The thalli taper into a distinct stipe below and are highly compressed. The width of the thallus is greater in the middle than at the base and may reach 5 cm in width. Ulva linza is bright light to dark green in colouration.

Recorded distribution in Britain and Ireland

Found throught the coasts of the British Isles and Ireland.

Global distribution



Ulva linza is a littoral and sublittoral species usually found on rocks or in rock pools, usually marine but occassionally found under brackish conditions.

Depth range


Identifying features

  • Thalli up to 30 cm in length, 5 cm in width.
  • Unbranched thalli with a frilled margin.
  • Thallus width greatest in the middle.
  • Bright green spring colouration.
  • Central cavity walls are closely adpressed, free only at the margins and the base.

Additional information

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Listed by

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Further information sources

Search on:


  1. Burrows, E.M., 1991. Seaweeds of the British Isles. Volume 2. Chlorophyta. London: British Museum (Natural History).

  2. Dickinson, C.I., 1963. British seaweeds. London & Frome: Butler & Tanner Ltd.

  3. Hardy, F.G. & Guiry, M.D., 2003. A check-list and atlas of the seaweeds of Britain and Ireland. London: British Phycological Society

  4. Howson, C.M. & Picton, B.E., 1997. The species directory of the marine fauna and flora of the British Isles and surrounding seas. Belfast: Ulster Museum. [Ulster Museum publication, no. 276.]

  5. National Biodiversity Network (NBN) Atlas website. Available from:  Accessed 01 April 2017

  6. OBIS,  2018. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2018-08-15


This review can be cited as:

Barnes, M.K.S. 2008. Ulva linza A green seaweed. In Tyler-Walters H. and Hiscock K. (eds) Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 15-08-2018]. Available from:

Last Updated: 22/05/2008