The Marine Life Information Network

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


Sea tamarisk (Tamarisca tamarisca)

Distribution data supplied by the Ocean Biodiversity Information System (OBIS). To interrogate UK data visit the NBN Atlas.Map Help



A colonial hydroid that grows up to 15 cm or more. It is straggly in appearance with alternate branches, widely spaced along the stem. The hydrothecae, a supporting, nonliving, protein-chitinous envelope surrounding the stem, is large, up to 1.6 mm long, tubular and variously outward curving. It is easily mistaken for a sparsely branched form of Abietinaria abietina but is distinguished by opposite hydrothecae.

Recorded distribution in Britain and Ireland

All British and Irish coasts.

Global distribution



A circalittoral species normally found in moderate to strong tidal streams attached to bedrock or stable rocks or shells.

Depth range


Identifying features

  • Colony 15 cm or more, straggly; monosiphonic throughout; branches alternate, widely spaced.
  • Male gonotheca kite-shaped, flattened, tapering to short pedicel below.
  • Female gonotheca conical, distal end hidden by two large, ragged flaps cut into several fingers.

Additional information

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Listed by


  1. Hayward, P.J. & Ryland, J.S. (ed.) 1995b. Handbook of the marine fauna of North-West Europe. Oxford: Oxford University Press.

  2. 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.]


  1. NBN (National Biodiversity Network) Atlas. Available from:

  2. OBIS (Ocean Biodiversity Information System),  2023. Global map of species distribution using gridded data. Available from: Ocean Biogeographic Information System. Accessed: 2023-06-08


This review can be cited as:

Wilson, E. 2002. Tamarisca tamarisca Sea tamarisk. In Tyler-Walters H. and Hiscock K. Marine Life Information Network: Biology and Sensitivity Key Information Reviews, [on-line]. Plymouth: Marine Biological Association of the United Kingdom. [cited 08-06-2023]. Available from:

Last Updated: 17/07/2002