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Chlorophyta, Green Algae

Ulva (Enteromorpha) intestinalis (Linnaeus) Nees

Chlorophyta, Order: Ulvales; Family: Ulvaceae. Current accepted name: Ulva intestinalis Linnaeus


Both the generic and species names of Ulva (Enteromorpha) intestinalis refer to the tubular shape of the thallus, which resembles an intestine.


The Ulva (Enteromorpha) intestinalis is a green, tubular alga. Most individuals are hollow and unbranched. Rarely, part of the thallus is flattened. In many cases, especially in mature individuals, the Ulva (Enteromorpha) intestinalis’ tube is replete with gasses. A microscopic overview shows cells scattered rather than arranged in groups. The cells are diamond- shaped or multi-lateral and slightly rounded. The chloroplast laminates; 2 Pyrenoids.


The Ulva (Enteromorpha) intestinalis is relatively small and reaches 15 cm in length, sometimes more. The thallus is between 0.5 and 5 cm wide.


The Ulva (Enteromorpha) intestinalis’s green tends to be lightcoloured, especially in mature individuals that have at some

time been dehydrated.

Special features

Ulva (Enteromorpha) intestinalis plants are relatively small, their tubes hollow, and they grow in the upper region of the intertidal zone, near land. The thallus is unbranched, and the cells are scattered.


The Ulva (Enteromorpha) intestinalis can be found in the area above the intertidal zone, near land. Mostly it densely populates shallow pools created by wave activity. Sometimes these pools are cut off from regular water supply for several hours and even days. The substrate is often rocky and sometimes sandy, or else sand covered rock.

Biology and reproduction

The basic life cycle and biology of the Ulva (Enteromorpha) intestinalis resembles that of the Ulva and other Ulva (Enteromorpha) species (see entry).

In some places around the world, the Ulva (Enteromorpha) intestinalis’ medical properties have been examined and the species found to be effective as an antibiotic against some bacterial species.

Seasonality and distribution

The alga is very common throughout the year. Its distribution is more or less universal.

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