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Chlorophyta, Green Algae

Caulerpa racemosa (Forsskål) J. Agardh

Chlorophyta, Order: Caulerpales; Family: Caulerpaceae.


Caulerpa, means ‘crawling stalk’. The species name means ‘a bunch’, and refers to the racemean shape of the thallus, which includes vesicles connected to a pedicle, resembling a bunch of green grapes.


The Caulerpa racemosa resembles a bunch of small green grapes. The ‘stalk’ is horizontal, and sprouts erect branches, upon which short branches hold globular, sometimes slightly elongated ‘leaves’. The species is generally quite varied.

The sub species that is common in the Mediterranean is more delicate than that which appears in the Red Sea or the Suez Canal.


Individuals collected in this region are relatively smaller and only gain a length of several dozen centimetres. In other places, individuals with ‘stalks’ of up to a meter and more have been found. The horizontal branches are usually less than 10 cm, and the diameter of the vesicles is less than 1 cm.


The alga varies in colour from dark-green to lawn-green. 

Special features

Green cysts arranged in clusters characterize the species, which is very heterogenic.


The Caulerpa racemosa has been reported in deep seas, reaching a depth of at least 50 m. It has also been reported in semi-exposed habitats of the intertidal zone. In Egypt, it is accompanied by Laurencia papillosa. The species has been found on both rocky and sandy substrates.

Seasonality and distribution

The species was first reported along the Israeli coast by Professor Rayss in 1941, and since then has been reported only a few of times. An individual was collected by her along the Beirut coast and has since been dried and

preserved at the Hebrew University Herbarium. Tikva Edelstein, in her doctoral thesis, mentions the species in deep water (1960); Likpin mentions it in Mikhmoret (1967,(1971; and Aharon Dotan, in his master’s thesis (1977), reports sightings in the islands the north of Israel in a list of located green algae.

The species is apparently very rare along Israeli coasts in spite of its Red Sea origin, and is found mostly in the north especially in deep water. The species which may have emigrated from the Red Sea, has since disappeared and may reappear in the future. Widespread colonies are known to exist in the deep waters off the Egyptian, Syrian, Turkish and Cypriot coasts. Additional reports from this area would be most welcome. As mentioned, the species is found in the Red Sea and is common in warm seas throughout the world.


The Caulerpa racemosa, like other species of Caulerpa, is a consumable item in the Far East; its protein content reaches 20% of its weight.

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