Sargassum longifructum

Thallus bushy, greenish-brown to darkbrown. Stem terete, 2–2.7 mm high, 3–4 mm diam., bearing several primary branches. Primary branches terete or slightly compressed, smooth, 2–3(–4.5) mm wide, 59–70 cm long. Phylloids from elongated-elliptical to lanceolate, to 4 cm long, 1.2–0.3 cm wide, irregularly dentate at the margins, with asymmetric base, obtuse or acute apices. Midrib vanishing below apex. Cryptostomata conspicuous, on both sides of the midrib. Vesicles spherical to elliptical rounded or sharply pointed, sometimes winged from one side, 3.5–5.1 mm wide, 4–7 mm long on terete, flattened or foliaceous stalk. Female receptacles flattened to triquetrous, to 7 mm long, 2 mm wide. Mail receptacles terete or slightly compressed, often twisted at the upper half, smooth, 1.2–3 cm long, 1–2 mm wide, simple or furcated, with a few marginal spines. Attachment by discoid or scutellate holdfast, 1–3 cm in diameter. Growing in the intertidal and subtidal zone on hard substratum.

China, Japan, Vietnam.