Sargassum yamadae

Thallus leathery, bushy, 0.4-1 m high. Main axis to 5 mm, terete (1.8 mm diam.), and bearing primary branches (compressed, flattened at base to triquetrous with sharp edges above, twisted). Secondary branches arranged alternately. Phylloids obovate-elongated, lanceolate to linear with round apices and serrate margins, of various size, 1.4-4.4 cm long, 4-8 mm broad. Midrib percurrent. Vesicles stalked, obovate, to 1.5 cm long, 4.5 mm broad, with flattened outgrowth at the top (to 2 cm long). Attachment by cone-shaped holdfast.

Japan, Korea.