Sargassum thunbergii

Thallus wiry, bushy, 30-100 cm high, dark brown to almost black. Main axis terete with phylloid scars, short (3-7 mm high), bearing above primary branches which are long in the lower half and short in the upper portion of thallus and covered with closely crowded clustered phylloids from all sides. Phylloids filiform, lanceolate, 4-10 mm long, 1-3 mm broad, with entire or coarse toothed margins. Vesicles stalked, small, elongate ellipsoidal or fusiform (to 5 mm long), extending into acute point. Plants dioecious with single or aggregate, long ellipsoidal or terete, slightly swollen receptacles, 5-15 mm long, develop in axils of phylloids. Attachment by small, flattened discoid holdfast with lobed margins. Growing on middle, low intertidal rocks, dead corals in open and sheltered calm shores.

Note: This species has a great potential value as food additives, medicinal supplements and preventive agents against cancer (Kim et al. 2009).

Tropics to temperate latitudes of Atlantic and Pacific Oceans.