An intertidal brown seaweed, found on the high shore. It grows up to 40 cm long, without air bladders and lives for up to 4 years. The species can tolerate a high level of desiccation. Fronds have a characteristic ridge along the edge of the receptacles.

Fucus spiralis is one of our commonest and most familiar seaweeds. It typically forms a zone high on rocky shores, below Pelvetia but above the other large brown seaweeds (e.g. Ascophyllum nodosum, Fucus vesiculosus) that characterise the mid-shore.

Well grown plants are usually easily recognisable by the flattened, twisted, dichotomously branched thallus, lacking bladders, and the large, oval receptacles at the frond tips, each receptacle being surrounded by a narrow rim of vegetative frond. Nevertheless, younger plants are not always so easy to identify, and even mature plants can be confused with F. ceranoides or with bladderless forms of F. vesiculosus. Both of these species, however, have narrower, more pointed, rimless receptacles.

Original publication: Linnaeus, C. (1753). Species plantarum, exhibentes plantas rite cognitas, ad genera relatas, cum differentiis specificis, nominibus trivialibus, synonymis selectis, locis natalibus, secundum systema sexuale digestas. Vol. 2 pp. [i], 561-1200, [1-30, index], [i, err.]. Holmiae [Stockholm]: Impensis Laurentii Salvii.

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Like other members of the Fucales, Fucus species are gametophytic diploids, lacking any separate haploid generation. Arguably the gametophyte itself is merely a transient cellular stage within the tissues of the receptacle. Pits in the receptacle are the conceptacles, which release egg cells (female gametes) and spermatozoids (motile male gametes) into the sea (forced out by the secretion of mucilage). Spermatozoids are chemically attracted (i.e. by a pheromone) to the egg cells, the resulting fertilised zygote eventually forming a new diploid plant.
Since, unusually for Fucus, F. spiralis is monoecious (i.e. lacks separate male and female plants), the conceptacles are hermaphrodite.

A more detailed analysis of the sexual cycle of Fucus is beyond the aim of this page, but can be found in textbooks such as van den Hoek et al. (1995).

Provide biological, medical and pharmacological activity - anticoalgulant; Contains: fucoidins/fucoidans

Source of hydrocolloids - source of alginate

Terrestrial plant and animal production - fertiliser; Contains: copper; iron; manganese; molybdenum; zinc.

Other uses: Fucus spiralis has been used historically for treatment of obesity, gout, goiter, and corns, and also in weight-reducing and revitalizing bath treatments. It has been used for cattle feed, and as an organic manure. This algae, regularly exposed to sun radiation and its oxidative consequences, has developed optimal bioelectronic characters. It has a high concentration of phloroglucinol derivatives, including phenol acid, and in turn has been used in products from companies in France and the UK such as nutritional supplements, skin serum, body lotion, and compounds and extracts used as ingredients in other skin and hair products.

Sixteen species of British marine algae were screened, of which four species, i.e. Laminaria digitata, L. hyperborea, Saccharina latissima and Fucus spiralis showed potent anticoagulant activity (Deacon-Smith et al., 1985)

Billard, E., Serrão, E.A., Pearson, G.A., Destombe, C. & Valero, M. (2010). Fucus vesiculosus and spiralis complex: a nested model of local adaptation at the shore level. Marine Ecology Progress Series 405: 163-174.

Billard, E., Serrao, E.A., Pearson, G.A., Engel, C.R., Destombe, C. & Valero, M. (2006). Analysis of sexual phenotype and prezygotic fertility in natural populations of Fucus spiralis, F. vesiculosus (Fucaceae, Phaeophyceae) and their putative hybrids. European Journal of Phycology 40(4): 397-407.

Braune, W. (2008). Meeresalgen. Ein Farbbildführer zu den verbreiteten benthischen Grün- Braun- und Rotalgen der Weltmeere. pp. [1]-596, 266 pls. Ruggell: A.R.G. Gantner Verlag.

Cerantola, S., Breton, F., Ar Gall, E. & Deslandes, E. (2006). Co-occurrence and antioxidant activities of fucol and fucophlorethol classes of polymeric phenols in Fucus spiralis. Botanica Marina 49: 347-351.

Coleman, M.A. & Brawley, S.H. (2005). Are life history characteristics good predictors of genetic diversity and structure? A case study of the intertidal alga Fucus spiralis (Heterokontophyta, Phaeophyceae). Journal of Phycology 41: 753-762.

Gabrielson, P.W., Widdowson, T.B. & Lindstrom, S.C. (2004). Keys to the seaweeds and seagrasses of Oregon and California. Phycological Contribution 6: iv + 181.

Loiseaux-de Goër, S. & Noailles, M.-C. (2008). Algues de Roscoff. pp. [1]-215, col. figs. Roscoff: Editions de la Station Biologique de Roscoff.

Mathieson, A.C., Dawes, C.J., Wallace, A.L. & Klein, A.S. (2006). Distribution, morphology, and genetic affinities of dwarf embedded Fucus populations from the Northwest Atlantic Ocean.. Botanica Marina 49: 283-303.

Perrin, C., Daguin, C., Van de Vliet, M., Engel, C.R., Pearson, G.A., & Serráo,E.A. (2007). Implications of mating system for genetic diversity of sister algal species: Fucus spiralis and Fucus vesiculosus (Heterokontophyta, Phaeophyceae). European Journal of Phycology 42: 219-230.

Powell, H.T. (1960). The typification of Fucus spiralis L. British Phycological Bulletin 2: 17.

Serrão, E.A., Alice, L.A. & Brawley, S.H. (1999). Evolution of the Fucaceae (Phaeophyceae) inferred from nrDNA-ITS. Journal of Phycology 35: 382-394, 5 figs, 4 tables.

Wallace, A.L., Klein, A.S. & Mathieson, A.C. (2004). Determining the affinities of salt marsh fucoids using microsatellite markers: evidence of hybridization and introgression between two species of Fucus (Phaeophyta) in a Maine estuary . Journal of Phycology 40: 1013-1027.

van den Hoek, C., Mann, D.G., & Jahns, H.M., (1995). Algae: and introduction to phycology. Cambridge University Press

English: Spiral Wrack

Other names: An chasfheamainn, casfheamainn, flat wrack, fucus spiralé, Kaurtang, kleine zee-eik, lav klørtang, platwier, Schraubentang, spiral wrack, spiraling rockweed, spiralled wrack, Spiraltang, varech spiralé.

Type locality: "in Oceano" [Atlantic Ocean] (Linnaeus 1753: 1159). Lectotype: OXF Herb. Sherard (Powell 1960: 17).

Notes: "However, in Species Plantarum the diagnosis for F. spiralis is followed by several references to earlier publications, and Linnaeus quotes as a synonym an entity named as "Fucus spiralis maritimum major" in Edition 3 of the Synonpsis of John Ray (1724). The plants on which this entity is based are in Herb. Sherard at Oxford, and I have established that they are true F. spiralis as at present understood; these plants can be used as an acceptable basis for the species Fucus spiralis L." (Powell 1960: 17).