From Wikipedia, the free encyclopedia
Jump to: navigation, search
Ceramium gracillimum var. byssoideum

100 µm basal part showing rhizoids (arrow)

Scientific classification
Domain: Eukaryota
(unranked): Archaeplastida
Division: Rhodophyta
Class: Florideophyceae
Order: Ceramiales
Family: Ceramiaceae
Genus: Ceramium

See list

Ceramium is a genus of red algae (or Rhodophyta). It is a large genus with at least 15 species in the British Isles.[1]


All species of Ceramium are small algae growing to no more than 30 cm (12 in) in length. They consist of a terete axis of cells surrounded by smaller cells forming a cortex. In most species this a continuous cortex enclosing the axis, in others the cortical cells are arranged only in nodes at the junction of cells of the axes. Species in the genus show irregular branching and are attached by unicellular or branched rhizoids.[1]


The species is dioecious forming spermatangia and carpogonia. The fertilised carpogonium develops growing parasitically attached to the female plant. Tetraspores are born in the cortical bands.[1]


Ceramium tenuicorne under epifluorescence microscope

British Isles[edit]

Scotland: Orkney and Faroes, Shetland, Ross and Cromarty, Fife.[1] England and Wales: Pembroke, Hampshire, Dorset, Devon and Cornwall, Sussex, Lincoln to Kent, Norfolk also the Channel Isles. Ireland: Cork, Kerry, Clare, Mayo, Waterford, Dublin, Donegal,[2] Antrim and Down.[1][3]


Some species are probably cosmopolitan. Widely in north-west Atlantic, Iceland, Norway to Spain, Denmark, Netherlands, France, Portugal, Mediterranean, Azores, Canary Islands, Cape Verde Islands, USA - Newfoundland to New York, Australia.[1]


  1. ^ a b c d e f Maggs, C.A. and Hommersand, M.H. 1993. Seaweeds of the British Isles. vol.1, Rhodophyta Part 3A Ceramiales. HMSO & Natural History Museum, London. ISBN 0-11-310045-0
  2. ^ Morton, O. 2003. The marine macroalgae of County Donegal, Ireland. Bulletin of the Irish Biogeographical Society 27:3 - 164
  3. ^ Morton,O. 1994. Marine Algae of Northern Ireland. Ulster Museum ISBN 0 900761 28 8

External links[edit]