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Rhodophyta, Red Algae

Ceramium Roth 1797

Rhodophyta, Order: Ceramiales; Family: Ceramiaceae.


The genus name derives from Greek for ‘small tube’ or ‘vase’.


The Ceramium resembles a bush made of filaments.  Microscopic examination reveals an elongated, multi-jointed  thallus. The joints are thick and comprise a ring of smaller  cells. The reproductive organs are dark and hidden inside  the joints. The branching is dichotomous, and at the end of  each branch, a pair of bent, pincer-like branches face each  other.


A tiny alga, its branches grow only a few centimeters in  length.


The algal is mostly transparent. Hints of red tending towards  brown appear in the joints.

Special features

The Ceramium resembles the Centroceras clavulatum, and  the two are easily confused. However, the Ceramium is  rarer, thicker, softer when touched and lighter.


The alga grows upon rocks and as an epiphyte upon other  plants. It is usually found on the sea-facing edges of the  abrasion platform and on rocks in the water.

Biology and reproduction

The Ceramium has a three-stage life cycle. It is a favourite  dish for algae-eating fish and other herbivores, and this is  probably the reason for its scarcity in areas exposed to fish.

Seasonality and distribution

The genus is quite common in most seas. In Israel, it can be  found year-round, although a rise in population is seen in  the warmer months.

Additional species

The genus includes dozens of species found worldwide. In  this region, about 16 species have so far been identified. A  partial list of these includes species classified in the  Mediterranean on different occasions:

Ceramium bertholdii Funk  

Ceramium ciliatum (Ellis) Ducluzeau  

Ceramium cimbricum H. Petersen  

Ceramium circinatum K.tzing  

Ceramium codii (Richards) G. Feldmann-Mazoyer  

Ceramium comptum B.rgesen  

Ceramium deslongchampii Chauvin and Duby  

Ceramium diaphanum (Lightfoot) Roth  

Ceramium echionotum J. Agardh  

Ceramium fastigiatum Harvey  

Ceramium flaccidum (Harvey and K.tzing) Ardissone  

Ceramium gracillimum (K.tzing) Griffiths and Harvey  

Ceramium nodulosum (Lightfoot) Ducluzeau  

Ceramium rubrum (Hudson) C. Agardh  

Ceramium strictum Gr.ville and Harvey

Ceramium - micrscopic structure of  

Ceramium tenuissimum (Roth) Areschough. the thallus.

Ceramium - a condensed, bracelet-like joint


Ceramium species have been used along Pacific shores to cure lung diseases and for the manufacture of cosmetics. One species, Ceramium rubrum, possibly present in the Eastern Mediterranean, contains antibiotic substances that arrest the growth of bacteria.

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