Sargassum wightii Greville 1848

    Thalli attached by basal disc shaped holdfast. Main axis cylindrical, simple, short, thick; primary branches distichously arranged smooth, up to 45 cm length, flattened; secondary branches up to 15 cm in length, flattened, arising at intervals of 3cm on the primary branches. Sterile lateral system consists of leafy segments upto 5 cm in length; up to 4-9 mm in breadth. Leaf petiolate, linear-lanceolate, oblong, margin subentire to entire, poorly denticulate, sinuate dentate towards the apex. Leaf shows acute to obtuse, tapering base and apex; costae sparse, cryptostomata scattered. Vesicles spherical to elliptical, apiculate; 5-8 mm long, 4 mm broad, stalked, stalk 5-8 mm long either leafy or very thin.

    Receptacles arising from the base of a leafy segment, more or less laxly divided in a cymose manner; segments simple, with a narrowed base, numerous, terete or angulate, upper segments often confluent to form a glomerulus, verrucose, often angulate at the apex; angular portion serrato-dentate. Receptacle bisexual, oogonial and antheridial conceptacles distinct. Antheridia are sessile or borne terminally or laterally on 1-3 celled stalk. Antheridial stalk cells are oblong to ellipsoidal, 6-12 µm long and 5-7 µm broad. Antheridia are oblong, 12-23 µm long and 4-12 µm broad.