top of page

Chlorophyta, Green Algae

Ulva (Enteromorpha) clathrata (Roth) Greville

Chlorophyta, Order: Ulvales; Family: Ulvaceae. Current accepted name: Ulva clathrata (Roth) C.Agardh


Ulva (Enteromorpha) refers to the tubular shape of the thallus, which resembles an intestine. The species name refers to the holes that are sometimes evident on the thallus. Although these holes are not an integral part of the plant’s natural growth, but rather caused by damage or harm by herbivores, they are characteristic to the species.


The Ulva (Enteromorpha) clathrata has a thin, tubular thallus from which numerous filamentous branches emanate. Often, the branching contains only one row of cells. An overview reveals differences in the cellular arrangement in the upper and lower parts of the thallus. Along the lower part, the cells are arranged randomly, while in the upper part they are usually in rows. The cells have various rectangular shapes. The chloroplast is dented or tooth-like (in various parts of the thallus, one finds different chloroplasts). The Pyrenoids are numerous 3-5-10.


The Ulva (Enteromorpha) clathrata is a small species. Its length is usually 10-15 cm. Size is affected by environmental conditions.


The Ulva (Enteromorpha) clathrata is shaded between greenish- yellow and dark-green.

Special features

The species’ Special features are the tubular shape and the (microscopic) filamentous branching. Holes are sometimes evident along the thallus.


The alga develops in the upper region of the intertidal zone.

Biology and reproduction

See description under Ulva.

Seasonality and distribution

The alga appears throughout the year. Its general distribution is more or less universal.

Additional species

There are several subspecies that are clearly different, especially with regard to the shape of the chloroplast, a result of lighting in the area.

bottom of page