Sargassum intermedium Tseng et Lu sp. nov. is characterized by its slender and linear leaves, entire or dentate at the margin; absence of, or obscure midrib; its vesicles being elliptical to subspherical when young, spherical when mature; its receptacles being compressed above and subcylindrical below, with elongated spinulate at the apex, a few in the laterals. It is related to S. acutifolium (Greville, 1848) differing in its leaves with obscure or no midrib and its vesicles, spherical when mature.

Sargassum qionghaiense Tseng et Lu sp. nov. is characterized by its flattened primary branches, broad below, narrower above; shorter and narrower, compressed, secondary branches; membranous leaves, thin and broad lanceolate, obtuse at the apex, obliquely cuneate at the base, denticulate at the margin, midrib being percurrent, obscure, with conspicuous, slightly raised, irregularly scattered cryptostomata. Vesicles small, subspherical when young, spherical when mature, mucronate or rounded at the apices, and foliaceous with midrib pedicels, entire or dentate at the margins. Plant androgynous. Receptacles flattened, usually forked, conspicuously spinulose at the apices and the sides, several in glomerules. The new species is related to S. binderi (J. Agardh, 1848), differing in its broad-lanceolate, thinner leaves, usually obtuse at the apex, with obscure midrib, smaller vesicles, smaller flattened receptacles.

Sargassum erumpens Tseng et Lu sp. nov. is characterized by (1) branches with raised open glandules; (2) leaves oblong to lanceolate, with a few raised open conspicuous cryptostomata: (3) vesicles spherical, with conspicuous raised open cryptostomata; (4) receptacles subcylindrical to slightly compressed, cymosely arranged in glomerutate. It is closely related to S. xishaense (Tseng C. K., Lu Baoren, 1979), but differs in its oblong leaves, furcate receptacles, cymosely arranged in glomerulate. The latter has large lanceolate leaves and biserrulus receptacles.