Sargassum tenerrimum

Thallus soft, slender, light brown to greenish brown, bushy, 30-50 cm high. Main axis very short (5 mm), terete (1 mm broad), bearing above irregularly alternately arranged primary cylindrical branches, with similar secondary branches and branchlets. Lower phylloids of primary branches oblonglanceolate with elongated cuneate base and short stipe, tapering to round apices, 6-7 cm long, 12-15 mm broad; midrib delicate, vanishing below the apex; margins irregularly sinuate-dentate; phylloids gradually smaller upwards. Cryptostomata large, scattered on both sides of the midrib. Vesicles stalked, spherical, ovate, to 3.5(-4) mm broad, often pointed. Receptacles 4-6 mm long, 0.5-1.5 mm broad, fusiform or slightly compressed, two- or three-edged, toothed at margins, forked. Holdfast discoid. Growing on subtidal rocks.

Tropics to temperate latitudes of Atlantic, Indian and Pacific Oceans.