Phaepohyta, Order: Fucales; Family: Cystoseiraceae.

Etymology

Cystoseira, means ‘chain of vesicles’, and it describes the air pockets in the thallus. Compressa refers to the flattened shape of the branches.

Description

The Cystoseira compressa is a brown bushy alga, with a holdfast comprised of a single unit (compact). It is unbranched and several short stipes emanate from it. The alga has two forms of branches: some flattened, which give the species its name, and some more cylindrical. The flotation vesicles are sunk within the side branches.

Size

Most individuals found measured between 15-30 cm in length, but larger ones can be found.

Colour

The Cystoseira compressa comes in shades of light brown and cream, sometimes uniformly and sometimes spotted. When dried, the thallus gains a darker shade.

Special features

The primary characteristic of the species is its flattened ‘stalks’ but, since some of the branches are cylindrical, several must be examined before determining the species.

Habitat

The Cystoseira compressa can be found in the upper regions of the intertidal zone, usually in places not exposed to the air, and where the current is not strong. It grows on rocky and sandy substrates in shallow pools.

Biology and reproduction

Most Cystoseira compressa individuals collected contain fruit organs (conceptacale). According to most reports, Cystoseira compressa - oxygen bubbles can be seen along the thallus’ surface, a result of photosynthesis. previously, the species was more prevalent. Although there is no difficulty in finding individuals of this species, there is some concern that the species may be under duress. The diminishing numbers may be a result of water quality deterioration in the Mediterranean. Since some species have been known to disappear from our coasts, attention must be given to the condition of Cystoseira colonies before they, too, reach a critical stage.

Seasonality and distribution

The Cystoseira compressa is a perennial species, common to our coast the year round, although in some seasons branches are shed and there is a decrease in population.

Additional species

In various publications, the Cystoseira compressa adopts various names, such as Cystoseira fimbriata (Desfontaines) Bory = Cystoseira abrotanifolia C. Agardh.