Amphiroa ( Amphiroa cryptarthordia )

/ / Marine Flora


Amphiroa cryptarthordia has an articulated calcareous structure whilst the thallus adopts a wide, dichotomic pattern (1; 2). The alga is approximately 20-40mm high with sessile conceptacles at the surface (1). Amphiroa has a dark-pink to light-pink colouration; the ramification is relatively irregular (1).

There are approximately 51 species within the genus Amphiroa (3); the species A. rigida has a similar appearance, but can be distinguished because it has more regular ramification (1). A. compressa, A. crustiformis and A. galapagensis are all listed under the IUCN Redlist (4).


A. cryptarthordia is found on hard, rocky substrates in sheltered areas; it has a preference for shade and is found from 0-25m (1).

Life Cycle

Amphiroa is an annual species; the gametophytes and sporophytes are morphologically similar (1).


A. cryptarthordia is distributed across the north-east Atlantic and in the Mediterranean (1).


A. cryptarthordia uses photosynthesis, as well as requiring various inorganic nutrients, such as carbon dioxide, phosphorus and fixed nitrogen (2).

Conservation Status

Not listed under the IUCN Redlist (4).


Description written by Ben Harvey (2009)

(1)   Cabioc’H, J., Floc’H, J. & Le Toquin, A., 1992. Guide mes algues des mers d’Europe. Paris: Delachaux et Niestle.

(2)   Graham, L.E. & Wilcox, L.W., 2000. Algae. New Jersey: Prentice-Hall Inc.

(3)   Guiry, M.D. (2009). Amphiroa J.V. Lamouroux, 1812. In: Guiry, M.D. & Guiry, G.M. (2009). AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. Accessed through the World Register of Marine Species at on 2009-09-02

(4)   IUCN, 2009. IUCN Red List of Threatened Species. [Online] (2009.1) Available at: [Accessed 01 September 2009].