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Name derivation:

Chondrus = L. chondro: hard, tough, or like cartilage; crispus =L. crispus: crisped, wavey crinkled.

Common names: Irish moss, black moss, carrageen, carragheen, Dorset weed, and Iberian moss


Chondrus  Stackhouse  1797;  19 of 175 species descriptions are currently accepted taxonomically (Guiry and Guiry 2014).

Order Gigartinales;  Family Gigartinaceae



Algae are foliaceous, bushy, firm, leathery, or fleshy, deep red to purple with a blue iridescence when submerged; grows attached by a crustose holdfast.  Axes are much dichotomously branched, compressed to blade like, and expanding from a slender stalk.  Its medulla consists of entangled, thick-walled filaments that form the subcortex and branch dichotomously to form a cortex of small pigmented cells.  Tetrasporangia are cruciate and occur in scattered dark-red sori. Cystocarpic sori often swell on one side of a blade.  Spermatangia forming whitish tips within gelatinous sori

Thalli exposed above sea level ten to bleach due to UV, freezing, and/or dessication, turning various shades of orange or yellow (carotenoids dominant), and finally white (all pigments oxidized).



Study of genome structure and metabolic features led to theory in which an ancestral red alga lost genes, introns, and intergenetic DNA due to ecological forces. Then due to activity of transposable elements, the genome got larger (Collén et al. 2013).

Similar genera:

The alga is often confused with Mastocarpus stellatus, whose blades bear cystocarpic papillae and curl under to the lower side, while C. crispus blades do neither.

Food Industry:

Chondrus is used an additive in food, carrageenans are water soluble hydrocolloids harvested from native populations (Sangha et al. 2013)


In the North Atlantic a common perennial  seaweed that forms dense stands on rocky ledges and large bolders of exposed coasts with little ice scouring; also present in the lower littoral zone and within mid-shore tide pools; extending to -30m . Found in semi-protected sites and estuarine habitats with strong tidal currents.



Collén, J., B. Porcel, W. Carré et al.  2013.  Genome structure and metabolic features in the red seaweed Chondrus crispus shed light on evolution of the Archaeplastida. Proceedings of the National Academy of Sciences. 110 (13): 5248-5252.

Guiry, M.D. and G.M. Guiry  2014.  AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 08 May 2014.

Sangha, J.S., D. Fan, A.H. Banskota, et al.  2013.  Bioactive components of the edible strain of red alga Chondrus crispus enhance xxidative stress tolerance in Caenorhabditis. Journal of Functional Foods. 5: 1180-1190.

Stackhouse, J.  1797.  Nereis britannica; continens species omnes fucorum in insulis britannicis crescentium: descriptione latine et anglico, necnon iconibus ad vivum depictis... Fasc. 2. pp. ix-xxiv, 31-70, pls IX-XIII. Bathoniae [Bath] & Londini [London]: S. Hazard; J. White.

Taylor, W. R.  1957. Marine Algae of the Northeastern Coast of North America. Revised edition. Univ. Michigan Press., Ann Arbor, ix + 509 pp.