Thallus 35 cm tall, with yellowish brown color, attached with discoid holdfast; main axis cylindrical and rough due to the presence of numerous outgrowth, supporting alternately arranged branches bearing leaves and vesicles; in young thalli leaves are longer and broader measuring 13 - 42 mm long including the stalk and 2.5 - 11.5 mm wide; leaves are generally oblong slightly tapered, retuse (slightly rounded)or emarginated at the tip finally serrated throughout the margin; mature thalli fewer leaves smaller, 7 - 15 mm long including stalk and 17 - 4 mm wide, oblanceolate, oblong with tapered bases, the apices are rounded, obtuse to acute outer margin is coarsely serrate; prominent midrib at a short distance from tr apex of the leaves; cryptostomates are scattered on the surface of the blade. pedunculate vesicles are ovate or spherical with a diameter of 1.5 - 3 mm.; these are tipped with spinose or thin leaf-like extensions and with few cryptostomates; vesicles may be solitary or may form clusters attached to the primary or secondary branches and are more numerous but smaller in mature thalli.

Uses: It forms a source for production of sodium alginate, animal feed, fertilizer and medicine

Abbott, I.A., Fisher, J. & McDermid, K.J. (2002). New reported and revised marine algae from the vicinity of Nha Trang, Vietnam. In: Taxonomy of Economic Seaweeds with reference to some Pacific species. Vol. VIII. (Abbott, I.A. & Mcdermid, K.J. Eds) Vol.8, pp. 291-321. Oceanographic Institute, Nha Trang, Vietnam: California Sea Grant College.

Ajisaka, T. (2002). Sargassum specimens from Singapore and Malaysia in the Herbarium of the Bishop Museum. In: Taxonomy of Economic Seaweeds with reference to some Pacific species. Vol. VIII. (Abbott, I.A. & Mcdermid, K.J. Eds) Vol.8, pp. 77-88. La Jolla: California Sea Grant College.

Ajisaka, T., Noro, T. & Yoshida, T. (1995). Zygocarpic Sargassum species (subgenus Sargassum) from Japan. In: Taxonomy of Economic Seaweeds. (Abbott, I.A. Eds) Vol.5, pp. 11-44. La Jolla, California: California Sea Grant College System.

Ajisaka, T., Phang, S.M. & Yoshida, T. (1999). Preliminary report of Sargassum species collected from Malaysian coasts. In: Taxonomy of Economic Seaweeds with reference to some Pacific species Vol. VII. (Abbott, I.A. Eds) Vol.7, pp. 23-41. La Jolla, California: California Sea Grant College System.

Chiang, Y.-M., Yoshida, T., Ajisaka, T., Trono, G., Jr, Tseng, C.K. & Lu Baoren (1992). Distribution and variation in Sargassum polycystum C.A. Agardh (Fucales, Phaeophyta). In: Taxonomy of Economic Seaweeds with reference to some Pacific and Western Atlantic species. (Abbott, I.A. Eds) Vol.3, pp. 35-42. La Jolla, California: California Sea Grant College.

Kraft, G.T. (2009). Algae of Australia. Marine benthic algae of Lord Howe Island and the southern Great Barrier Reef, 2. Brown algae. pp. [i-iv], v-vi, 1-364, 107 figs. Erratum of fig. 73 from vol. 1. Canberra & Melbourne: Australian Biological Resources Study and CSIRO Publishing.

Mattio, L. & Payri, C.E. (2009). Taxonomic revision of Sargassum species (Fucales, Phaeophyceae) from New Caledonia based on morphological and molecular analyses. Journal of Phycology 45(6): 1374-1388.

Mattio, L., Payri, C.E. & Verlaque, M. (2009). Taxonomic revision and geographic distribution of the subgenus Sargassum (Fucales, Phaeophyceae) in the western and central Pacific islands based on morphological and molecular analyses. Journal of Phycology 45(5): 1213-1227.

Type locality: Sunda Strait, Indonesia (Silva, Basson & Moe 1996: 694). Syntypes: TCD 1108, 1109 (Mattio et al. 2009: 1222). 

Taxonomic notes: According to Silva et al. (1996) the following taxa apparently lie within the circumspection of this species but have not yet been transferred or reduced to synonymy: Sargassum brevifolium var. pergracile Grunow Sargassum brevifolium [var. pergracile] forma subecostatum Grunow

Previously in section Zygocarpicae. Matteo et al. (2009: 1222) place this species in subgenus Sargassum, section Polycystae Mattio & Payri 2009: 1220. - (19 Jan 2010) - Wendy Guiry