Thallus dark green (sometimes bluish), stiff, entwined, to 200 mm in length, composed of profusely, irregularly branched filaments apparent to the unaided eye. Attached by a rhizoidal holdfast. Persists throughout the year.

Cladophora rupestris is a densely tufted plant, that grows up to 20 cm in height, with dark green or bluish coloured dull fronds. Typical specimens branch profusely upwards from the base, in an irregular, whorled or opposite pattern. The stoutness, density and arrangement of branches gives the seaweed a coarse feel.

The morphology of the species is fairly constant over a wide range of habitat conditions and over a wide geographical area. Its morphology is affected by physical damage due to grazing by animals and loss of the apical region on reproduction, both instances are followed by regeneration and proliferation of branches. Cladophora rupestris sometimes forms an almost complete cover of stunted growth at high tide level and occasionally in the splash zone where pools are brackish. Filaments are short and branching dense in the most wave exposed locations.

Link for (Pereira, 2010) Handbook Guide

Original publication: Kützing, F.T. (1843). Phycologia generalis oder Anatomie, Physiologie und Systemkunde der Tange... Mit 80 farbig gedruckten Tafeln, gezeichnet und gravirt vom Verfasser. pp. [part 1]: [i]-xxxii, [1]-142 , [part 2:] 143-458, 1, err.], pls 1-80. Leipzig: F.A. Brockhaus.

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Contains: arabinose; carotenoids; galactose; glucose; polysaccharides; protein; rhamnose; sulfuric acid; xylose.

Fisher, I. S. & Percival, E. E. (1956). Water soluble polysaccharide of Cladophora rupestris. Proceedings of the International Seaweed Symposium 2: 5-9.

Jónsson, S. & Chesnoy, L. (1971). Méiose et sporogenèse chez le Cladophora rupestris (L.) Kütz.. Compte Rendu Hebdomadaire des Séances de l’Académie des Sciences. Paris. Série D 272: 1754-1756.

Jónsson, S. & Perrot, Y. (1967). Le cycle de reproduction du Cladophora rupestris (L.) Kütz., (Cladophoracées). Compte Rendu Hebdomadaire des Séances de l’Académie des Sciences. Paris. Série D 264: 2628-2631.

Kylin, H. (1944). Zur biochemie von Cladophora rupestris. Kungliga Fysiografiska Sällskapets i Lund. Förhanlingar 14: 1-5.

Thomas, D.N., Collins, J.C. & Russell, G. (1988). Interactive effcts of temperature and salinity upon net photosynthesis of Cladophora glomerata (L.) Kütz. C. rupestris (L.) Kütz.. Botanica Marina 31: 73-77.

Wiencke, C. & Davenport, J. (1987). Respiration and photosynthesis in the intertidal alga Cladophora rupestris (L.) Kütz. under fluctuating salinity regimes. Journal of Experimental Marine Biology and Ecology 114: 183-197.

Basionym: Conferva rupestris Linnaeus

Type locality: Habitat in Europeae marinis rupibus copioissima [Bognor Regis, Sussex, England] (Linnaeus 1753: 1167). Lectotype: OXF herb. Dillenius (Hoek 1969: 19, 64). Notes: Herb. Dillenius as Conferva marina trichodes ramosior Dillenius, 1741, upper specimen and lower left-hand specimen of the herbarium sheet.