University of Hawai`i

Botany Department

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Sargassum polyphyllum

J.Adardh 1848




Class Order Family
Phaeophyta Phaeophyceae Fucales Sargassaceae

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Sargassum polyphyllum, or limu kala, is an endemic Hawaiian species common on wave swept benches. Thick, bushy thalli with spines on the main axes are characteristics unique
to this species, compared to the other Sargassum species.
















Sargassum polyphyllum on reef flat at Waikiki, O‘ahu.



Tough, bushy, erect thallus, 4 - 70 cm tall. Plant consists of a primary axes, rounded or slightly compressed below first or second blade, 0.5 - 4 mm diam., with spines. Plants usually highly branched, with secondary branches variable, some short compared to primary branch on some plants, and as long as primary branch on others. Blades narrow, oblong, and either flat or spirally twisted, 1 - 6 cm long, 0.1 - 0.8 cm wide, with short flattened petiole, petiole usually with spines. Blade margins are often spiny, occasionally smooth, wavy or straight, with spines or wings developing on upper or lower surface of blade midrib.

S. polyphyllum varies greatly in different habitats. Plants from high and mid intertidal are usually shorter, bushier (less than 20 cm tall), blades shorter with smooth or tooth-like margins, and with no vesicles. Subtidal plants are usually larger and longer, with blades more narrowly elliptical or oblong, and with vesicles.  Light golden brown to dark brown.


Structural Features

Thalli dioecious, fertile branches have receptacles; elongate hermaphroditic structures that house the male conceptacles with the male antheridia, which produce sperm, and the and female conceptacles, with female oogonia, which hold the ova. Nonreproductive conceptacles are visible on the leaf surface as dark spots.



Sargassum polyphyllum is found on wave-swept benches, tidepools and on reef flats. It is often heavily epiphytized by Hypnea sp.,and Ulva reticulata on shallow, calm reef flats, and is found with S. echinocarpum or S. obtusifolium on high energy benches.


Hawai‘i:  Kaua‘i, Moloka‘i, Oah‘ u, Maui, Lana‘i, and Hawai‘i Island.

Worldwide:  Endemic to Hawai‘i.



Like most other endemic species, little research has been done on the endemic Sargassum polyphyllum. This common brown alga is often found in communities with S. obtusifolium and S. echinocarpum on wave swept benches with high energy and subtidally on reef flats.


In mature algal communties, Sargassum spp. can account for a large part of the biomass. In a 1971-1973 study, approximately 70 percent of the total biomass at Waikiki was identified as S. polyphyllum, which was highly correlated with antecendent water tempertures. These plants can grow quite large, overcoming competitors for space by overgrowth and shading, and may form dense communities, thus inhibiting recruitment by other algae. They are often epiphytized and it is not uncommon to find Hypnea spp. and Ulva reticulata attached to the upper branches and blades.


Sargassum polyphyllum has great variation in its morphology. This alga can withstand a wide range of environmental conditions: it is found in areas of high salinity, high wave action, and changing temperatures. Reproduction is by vegetative fragmentation or sexual reproduction.


Abbott, I.A., 2001. Unpublished manuscript.

Glenn, E.P., C.M. Smith, and M.S. Doty, 1990. Influence of antecendent water temperatures on standing crop of a Sargassum spp.-dominated reef flat in Hawai‘i. Mar. Biol. 105: 323-328.

Magruder, W.H., and J.W. Hunt, 1979. Seaweeds of Hawai‘i. Oriental Publ. Co., Honolulu, Hawai‘i.

 Web Pages

Frondose Algae of Waikiki.

Hawaiian Reef Algae.


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