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Chlorophyta, Green Algae

Codium vermilara (Olivi) Delle Chiaje

Chlorophyta , Order: Caulerpales; Family: Codiaceae. The Codium vermilara is most possibly the species described in literature as Codium dichotomum Gara = Codium taylorii Silva. Often, these are described as separate species, but in most research, especially recently, Codium vermilara and Codium taylorii are distinguished.


Codium, means ‘sheep’, and the algal texture indeed resembles that of sheepskin. The name suggests softness of touch and also refers to the hair around the thallus. Until now, we have not managed to ascertain definitively the source of the scientific name for the species, vermilara, which means ‘worm’ or ‘wormy’, and the name may be a result of the worm-like shape of the alga, or because it used to be a source for manufacturing anti-stomach worm potions.


The Codium vermilara is an erect, bushy and tangled alga whose cylindrical branches and branching are irregular, sometimes dichotomous. Often the horns are unequal in size, and they usually do not grow on the same plane. Proliferation is common (i.e. a young ‘leaf’ develops on the back of a mature ‘leaf’) . The Codium vermilara connects to a substrate using a flat holdfast. Close inspection with a magnifying glass or when the plant matures reveals a dense hairy covering on the surface, like velvet.


The height and diameter of the entire plant reaches 10 cm. The branches grow beyond 3 mm thick.


The Codium vermilara is dark green.

Special features

The Codium genus has a spongy appearance and velvety touch that eases identification of the genus. The Codium vermilara is dichotomously branched, usually in an irregular manner, and its branches are flattened. Definitive identification requires a microscope or examination of the tissue structure.


The alga appears in rocky and sandy habitats. The profusion of individuals often indicates the infiltration of sewage into the sea. Frequently, Codium vermilara can be found in potholes. In other countries, species of Codium have been reported in deep sea; however, the species in this region do not venture into deep water. They are usually not covered by epiphytes.

Biology and reproduction

Most species in this genus are dark green, and they all have a similar internal structure: a mass of thin filaments are located at the center of the thallus. These filaments are tangled, multi-nuclear and nearly void of chlorophyll. Large and elongated vesicular branches grow out of each filament. The cysts are also multi-nuclear, but they are very rich in chloroplasts. These cysts, whose length is 0.5-1 mm each, provide the alga with its velvety appearance.

The Codium is a diploid alga that reproduces sexually. The reproductive organs resemble small corpuscles that develop on the cysts. The alga is dioecious, and its male reproductive cells are smaller than its female ones. The reproductive cells are discharged into the water as a mucousy gob, which then scatters.

Under conditions of nitrogen deficiency, species of Codium develop symbiosis with nitrogen-binding bacteria that settle in the Codium’s thallus. Another form of symbiosis is a result of Codium being consumed by molluscs: the chloroplasts continue to survive within the host, providing them with energy for several months after their consumption, on condition, of course, that the herbivore lives in a well lit area.

Seasonality and distribution

Codium vermilara may be found in the Eastern Mediterranean the year round, The chances of finding good reproductive cells is better in the autumn, though. The species can also be found in the Atlantic Ocean, the Canary Islands, the Indian Ocean and the Mediterranean.

Additional species

Along Israeli coasts, both the Codium vermilara and the Codium decorticatum may be found. In various publications, additional names appear, but these are apparently alternative names for the same two species. In some sources, the Codium vermilara and the Codium decorticatum appear synonymously; however, I believe that at least two different species exist along the coast.


Many species of Codium are eaten by humans and also by marine animals. In North East Asia the Codium is used as medicament against worms in the intestines, mostly against Ascaris. Because of its special shape, the Codium got various popular names such as: “Oyster thief”, “Dead man’s fingers” or “Spaghetti grass”.

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