Phaeophyceae (Brown Algae)

Phaeophyceae, the brown algae, owe their colour to the accessory pigment fucoxanthin masking their chlorophyll.

Habitat. Mostly marine, only rarely found in fresh water.

Body form. Ranges from simple branched or filamentous forms (e.g. Ectocarpus) to profusely branched forms (e.g. Petalonia). In the larger members the body is differentiated into three regions: a holdfast that anchors the plant, a stalk-like stipe, and a flattened, leaf-like photosynthetic frond.

Cell wall and pigments. The cell wall contains cellulose, fucans and algin. Photosynthetic pigments include chlorophyll a and c, along with fucoxanthin.

Stored food. Reserve food is stored as mannitol, laminarin and starch. …