Sargassum polycystum C. Agardh
Rough-stemmed sargassum
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Family:  Sargassaceae ()
Max. size: 
Environment:  sessile; marine; depth range 0 - 63 m
Distribution:  Atlantic and Indo-Pacific oceans: Canary Islands; from Kenya to Madagascar, including Seychelles and Mauritius, east to India and south to Indonesia, including Bay of Bengal and Andaman Islands; from China to the South China Sea, south to Australia, including Xisha Islands, Guam, Northern Mariana Islands, Federated States of Micronesia, New Caledonia, Tonga and Fiji.
Diagnosis:  Thalli large, dark brown to yellowish brown, attached to rocks by a coarse branching holdfast; stem short cylindrical. Primary branches terete, bearing irregularly alternate secondary branches with numerous simple and Y-shaped proliferations. Mature thalli with fewer and smaller oblanceolate leaves, 7 to 15 mm long and 1.5 to 4 mm wide, with coarsely dentate or serrated margins; midrib prominent up to near the apex. Cryptostomata scattered on the surface of leaves. Stalked vesicles ovate or spherical, numerous; vesicles attached to the secondary, tertiary and terminal branches either singly or in clusters, 1.0 to 2.5 mm in diameter, bearing few cryptostomata and/or teeth-like structures. Plant dioecious. Male receptacles racemose-paniculate, receptacular branches terete, warty. Female receptacles small, cymose; receptacular branches short, dense, compressed, simple or forked with teeth or spines at margins. Thalli up to 40 cm in height (Ref. 80758).
Biology:  Used as fertilizer, as human food, fodder and medicine; contains auxin-like substance; controls heavy metal (Pb, Cd) pollution; also a source of alginate; may form dense stands and is therefore considered as a good biomass source for biogas production; used as soil fertilizer (Ref. 80758). Usually thrives in inner reef areas on coarse, sandy coralline substrate, not exposed to strong water turbulence (Ref. 80758).
IUCN Red List Status: Not Evaluated (N.E.) Ref. 123251)
Threat to humans:  harmless
Country info:   
 

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