Fucus tendo L. Fucus vesiculosus L. – bladder wrack * Fucus virsoides J. Agardh * Species recorded around the coast of Britain. Fucus distichus F. distichus is up to 10 cm long with a short stout cylindrical stipe, branching dichotomous, flat and with a mid-rib. F. distichus subsp. edentatus was first described from Shetland by Börgesen in 1903. Powell found F. distichus subsp. anceps on the north coast of Caithness. It had also been recorded from: Orkney, Fair Isle, St Kilda and the Outer Hebrides in Scotland; in Ireland it had been recorded from Counties Clare, Donegal and Kerry. Two subspecies of F. distichus (subsp. anceps and subsp. edentatus) have been described from the British Isles. Fucus distichus is the organism used as a model to study the development of cell polarity, since it forms an apolar zygote that can develop polarity given a varying number of gradients. Fucus serratus F. serratus, toothed wrack, is the most distinctive of all the Fucus species. It clearly shows a distinctive serrated edge to the frond not shown by the other species of the genus. Fucus spiralis F. spiralis is one of the three most common algae on the shores of the British Isles. It grows to about 40 cm long and does not show air bladders as found on F.vesiculosus or toothed edges as found on F. serratus. It forms a zone near the top of the shore above the zones of F. vesiculosus and F. serratus. Fucus vesiculosus This is one of the most common species of Fucus, common on most shores in the mid-littoral. It has the common name "bladder wrack", and is readily identified by a distinct mid-rib and air vesicles in pairs on either side of the mid-rib. Notes References Fucales genera Fucaceae